From 10ec304283353ad05bdb6daee1c63de47d11e87c Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 19:23:23 +0100
Subject: [PATCH 01/74] Setup a plugin to run a flow checking lifecycle

This will only run if a @flow annotation is seen:
- At the first @flow file found:
  - Write a .flowconfig if none exists
  - [Not done yet] Run flow-typed install
  - [Not done yet] Start a flow instance
- When a file with an @flow comment changes during a compilation:
  - [Not done yet] Run a flow check
  - If there are some errors in flow:
    - If CI: output as an error
    - If not CI: output as a warning
---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 83 +++++++++++++++++++
 packages/react-dev-utils/package.json         |  1 +
 .../config/webpack.config.dev.js              | 13 ++-
 3 files changed, 96 insertions(+), 1 deletion(-)
 create mode 100644 packages/react-dev-utils/FlowTypecheckPlugin.js

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
new file mode 100644
index 00000000000..ff4d8bd3500
--- /dev/null
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -0,0 +1,83 @@
+var fs = require('fs');
+var path = require('path');
+
+function FlowTypecheckPlugin(options) {
+  this.options = options || {};
+  // If flow is globally present in the project, this will stay across compilations
+  this._flowInitialized = false;
+  // If flow should run in a current compilation
+  this._flowShouldRun = false;
+  // Stores the last flow output
+  this._flowOutput = "";
+}
+
+FlowTypecheckPlugin.prototype.apply = function(compiler) {
+  compiler.plugin('compilation', function(compilation, params) {
+    // Detect the presence of flow and initialize it
+    compilation.plugin('normal-module-loader', function(loaderContext, module) {
+      // We're only checking the presence of flow in non-node_modules
+      // (some dependencies may keep their flow comments, we don't want to match them)
+      if (module.resource.indexOf("node_modules") < 0) {
+        // We use webpack's cached FileSystem to avoid slowing down compilation
+        loaderContext.fs.readFile(module.resource, function(err, data) {
+          if (data && data.toString().indexOf('@flow') >= 0) {
+            if (!this._flowInitialized) {
+              this._initializeFlow(compiler.options.context);
+              this._flowInitialized = true;
+            }
+            this._flowShouldRun = true;
+          }
+        }.bind(this));
+      }
+    }.bind(this))
+  }.bind(this));
+
+  // While emitting run a flow check if flow has been detected
+  compiler.plugin('emit', function(compilation, callback) {
+    // Only if a file with @ flow has been changed
+    if (this._flowShouldRun) {
+      this._flowOutput = this._flowCheck();
+      this._flowShouldRun = false;
+    }
+    if (this._flowOutput.length > 0) {
+      // In a CI, we wish to get flow breaking the build so we write errors here
+      if (process.env.CI) {
+        compilation.errors.push(this._flowOutput);
+      } else {
+        compilation.warnings.push(this._flowOutput);
+      }
+    }
+    callback();
+  }.bind(this));
+};
+
+// This initializer will run once per webpack run (runs once across all compilations)
+FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath) {
+  const flowconfigPath = path.join(projectPath, '.flowconfig');
+  fs.exists(flowconfigPath, function(exists) {
+    if (!exists) {
+      fs.writeFile(flowconfigPath, (this.options.flowconfig || []).join('\n'));
+    }
+  }.bind(this));
+  // TODO: run flow-typed
+  // TODO: start a flow instance
+};
+
+// This check will run each time a compilation sees a file with @ flow change
+FlowTypecheckPlugin.prototype._flowCheck = function() {
+  // TODO: run a single flow check
+  return `
+src/App.js:11
+ 11: f("abc");
+     ^^^^^^^^ function call
+ 11: f("abc");
+       ^^^^^ string. This type is incompatible with
+  7: function f(x: number) {
+                   ^^^^^^ number
+
+
+Found 1 error
+  `;
+};
+
+module.exports = FlowTypecheckPlugin;
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index b7660595454..34aad38931f 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -12,6 +12,7 @@
   },
   "files": [
     "clearConsole.js",
+    "FlowTypecheckPlugin.js",
     "checkRequiredFiles.js",
     "formatWebpackMessages.js",
     "getProcessForPort.js",
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 96fd632b795..97fdb25913d 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -15,6 +15,7 @@ var HtmlWebpackPlugin = require('html-webpack-plugin');
 var CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
 var InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
 var WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
+var FlowTypecheckPlugin = require('react-dev-utils/FlowTypecheckPlugin');
 var getClientEnvironment = require('./env');
 var paths = require('./paths');
 
@@ -226,7 +227,17 @@ module.exports = {
     // to restart the development server for Webpack to discover it. This plugin
     // makes the discovery automatic so you don't have to restart.
     // See https://github.com/facebookincubator/create-react-app/issues/186
-    new WatchMissingNodeModulesPlugin(paths.appNodeModules)
+    new WatchMissingNodeModulesPlugin(paths.appNodeModules),
+    // Trigger some typechecking if a file matches with an @ flow comment
+    new FlowTypecheckPlugin({
+      flowconfig: [
+        '[ignore]',
+        '<PROJECT_ROOT>/node_modules/fbjs/.*',
+        '',
+        '[libs]',
+        './flow-typed'
+      ]
+    })
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.

From c7eacf89622f782df6698264d4fe350ece332295 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 19:35:16 +0100
Subject: [PATCH 02/74] Make flow fail on CI builds

We don't need complex logic with process.env on the plugin side, we let the build script figure this out!
---
 packages/react-dev-utils/FlowTypecheckPlugin.js      |  8 ++------
 packages/react-scripts/config/webpack.config.prod.js | 10 +++++++++-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index ff4d8bd3500..e815d7b14ed 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -39,13 +39,9 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
       this._flowOutput = this._flowCheck();
       this._flowShouldRun = false;
     }
+    // Output a warning if flow failed
     if (this._flowOutput.length > 0) {
-      // In a CI, we wish to get flow breaking the build so we write errors here
-      if (process.env.CI) {
-        compilation.errors.push(this._flowOutput);
-      } else {
-        compilation.warnings.push(this._flowOutput);
-      }
+      compilation.warnings.push(this._flowOutput);
     }
     callback();
   }.bind(this));
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index 058db0d7921..82d6eb318f1 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -15,6 +15,8 @@ var HtmlWebpackPlugin = require('html-webpack-plugin');
 var ExtractTextPlugin = require('extract-text-webpack-plugin');
 var ManifestPlugin = require('webpack-manifest-plugin');
 var InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
+var SubresourceIntegrityPlugin = require('webpack-subresource-integrity');
+var FlowTypecheckPlugin = require('react-dev-utils/FlowTypecheckPlugin');
 var url = require('url');
 var paths = require('./paths');
 var getClientEnvironment = require('./env');
@@ -268,7 +270,13 @@ module.exports = {
     // having to parse `index.html`.
     new ManifestPlugin({
       fileName: 'asset-manifest.json'
-    })
+    }),
+    // Generate and inject subresources hashes in the final `index.html`.
+    new SubresourceIntegrityPlugin({
+      hashFuncNames: ['sha256', 'sha384']
+    }),
+    // Run Flow only if we see some @ flow annotations, will error on CI
+    new FlowTypecheckPlugin({})
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.

From b0c39e7a1a2e0a26dc21a80b3f7184be4c357809 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 22:05:36 +0100
Subject: [PATCH 03/74] Run flow as a server and check with status

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 80 ++++++++++++++-----
 packages/react-dev-utils/package.json         |  1 +
 .../config/webpack.config.dev.js              |  3 +-
 3 files changed, 62 insertions(+), 22 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index e815d7b14ed..6dc631aa7e9 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -1,5 +1,7 @@
 var fs = require('fs');
 var path = require('path');
+var flowBinPath = require('flow-bin');
+var childProcess = require('child_process');
 
 function FlowTypecheckPlugin(options) {
   this.options = options || {};
@@ -9,6 +11,8 @@ function FlowTypecheckPlugin(options) {
   this._flowShouldRun = false;
   // Stores the last flow output
   this._flowOutput = "";
+  // Flow server process
+  this._flowServer = null;
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
@@ -36,14 +40,27 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
   compiler.plugin('emit', function(compilation, callback) {
     // Only if a file with @ flow has been changed
     if (this._flowShouldRun) {
-      this._flowOutput = this._flowCheck();
       this._flowShouldRun = false;
+      var version = this.options.flowVersion || 'latest';
+      this._flowCheck(compiler.options.context, version, function(err, flowOutput) {
+        if (err) {
+          compilation.errors.push(err.message);
+          return callback();
+        }
+        this._flowOutput = flowOutput;
+        // Output a warning if flow failed
+        if (this._flowOutput.indexOf('No errors!') < 0) {
+          compilation.warnings.push(this._flowOutput);
+        }
+        callback();
+      }.bind(this));
+    } else {
+      // Output a warning if flow failed in a previous run
+      if (this._flowOutput.length > 0 && this._flowOutput.indexOf('No errors!') < 0) {
+        compilation.warnings.push(this._flowOutput);
+      }
+      callback();
     }
-    // Output a warning if flow failed
-    if (this._flowOutput.length > 0) {
-      compilation.warnings.push(this._flowOutput);
-    }
-    callback();
   }.bind(this));
 };
 
@@ -56,24 +73,45 @@ FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath) {
     }
   }.bind(this));
   // TODO: run flow-typed
-  // TODO: start a flow instance
+  this._flowServer = childProcess.spawn(
+    flowBinPath,
+    ['server'],
+    { cwd: projectPath }
+  );
 };
 
 // This check will run each time a compilation sees a file with @ flow change
-FlowTypecheckPlugin.prototype._flowCheck = function() {
-  // TODO: run a single flow check
-  return `
-src/App.js:11
- 11: f("abc");
-     ^^^^^^^^ function call
- 11: f("abc");
-       ^^^^^ string. This type is incompatible with
-  7: function f(x: number) {
-                   ^^^^^^ number
-
-
-Found 1 error
-  `;
+FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb) {
+  var flowOutput = "";
+  var flowErrOutput = "";
+  var statusCheck = childProcess.spawn(
+    flowBinPath,
+    ['status', '--no-auto-start', '--color=always'],
+    { cwd: projectPath }
+  );
+  statusCheck.stdout.on('data', function(chunk) {
+    flowOutput += chunk.toString();
+  });
+  statusCheck.stderr.on('data', function(chunk) {
+    flowErrOutput += chunk.toString();
+  });
+  statusCheck.on('close', function() {
+    if (flowErrOutput.length > 0) {
+      if (flowErrOutput.indexOf("There is no Flow server running") >= 0) {
+        return cb(new Error(
+          'flow server: unexpectedly died.\n' +
+          'This is likely due to a version mismatch between a global flow ' +
+          'server (that you or your IDE may try to run) and react-script\'s ' +
+          'flow server.\n' +
+          'You should run: \n' +
+          'npm install -g flow-bin@' + flowVersion
+        ));
+      } else if(flowErrOutput.indexOf("still initializing") < 0) {
+        return cb(new Error(flowErrOutput));
+      }
+    }
+    cb(null, flowOutput);
+  });
 };
 
 module.exports = FlowTypecheckPlugin;
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index 34aad38931f..063c87153d4 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -27,6 +27,7 @@
     "ansi-html": "0.0.5",
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
+    "flow-bin": "^0.36.0",
     "html-entities": "1.2.0",
     "opn": "4.0.2",
     "sockjs-client": "1.0.3",
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 97fdb25913d..20f46521887 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -236,7 +236,8 @@ module.exports = {
         '',
         '[libs]',
         './flow-typed'
-      ]
+      ],
+      flowVersion: "0.36.0",
     })
   ],
   // Some libraries import Node modules but don't use them in the browser.

From de16269da97a9f19a93ab3d1c01708d6d41f9e8a Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 22:20:25 +0100
Subject: [PATCH 04/74] Add flow ignore comment to the start hints

---
 packages/react-scripts/scripts/start.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/react-scripts/scripts/start.js b/packages/react-scripts/scripts/start.js
index 3e71e2de886..0e11ef0321f 100644
--- a/packages/react-scripts/scripts/start.js
+++ b/packages/react-scripts/scripts/start.js
@@ -131,6 +131,7 @@ function setupCompiler(host, port, protocol) {
       console.log('You may use special comments to disable some warnings.');
       console.log('Use ' + chalk.yellow('// eslint-disable-next-line') + ' to ignore the next line.');
       console.log('Use ' + chalk.yellow('/* eslint-disable */') + ' to ignore all warnings in a file.');
+      console.log('Use ' + chalk.yellow('// $FlowFixMe') + ' to ignore flow-related warnings on the next line.');
     }
   });
 }

From 31b2e042574e31e4d6e0fac2d3ec622bbf6638be Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 23:11:52 +0100
Subject: [PATCH 05/74] Add flow-typed resolution at start

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 47 ++++++++++++++-----
 packages/react-dev-utils/package.json         |  1 +
 .../config/webpack.config.dev.js              |  3 ++
 .../config/webpack.config.prod.js             |  7 ++-
 4 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 6dc631aa7e9..d5042538449 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -1,7 +1,8 @@
 var fs = require('fs');
 var path = require('path');
-var flowBinPath = require('flow-bin');
 var childProcess = require('child_process');
+var flowBinPath = require('flow-bin');
+const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
 
 function FlowTypecheckPlugin(options) {
   this.options = options || {};
@@ -10,12 +11,14 @@ function FlowTypecheckPlugin(options) {
   // If flow should run in a current compilation
   this._flowShouldRun = false;
   // Stores the last flow output
-  this._flowOutput = "";
+  this._flowOutput = '';
   // Flow server process
   this._flowServer = null;
+  this._flowServerStderr = '';
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
+  var version = this.options.flowVersion || 'latest';
   compiler.plugin('compilation', function(compilation, params) {
     // Detect the presence of flow and initialize it
     compilation.plugin('normal-module-loader', function(loaderContext, module) {
@@ -26,7 +29,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         loaderContext.fs.readFile(module.resource, function(err, data) {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!this._flowInitialized) {
-              this._initializeFlow(compiler.options.context);
+              this._initializeFlow(compiler.options.context, version);
               this._flowInitialized = true;
             }
             this._flowShouldRun = true;
@@ -41,7 +44,6 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     // Only if a file with @ flow has been changed
     if (this._flowShouldRun) {
       this._flowShouldRun = false;
-      var version = this.options.flowVersion || 'latest';
       this._flowCheck(compiler.options.context, version, function(err, flowOutput) {
         if (err) {
           compilation.errors.push(err.message);
@@ -65,19 +67,40 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
 };
 
 // This initializer will run once per webpack run (runs once across all compilations)
-FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath) {
+FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersion) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   fs.exists(flowconfigPath, function(exists) {
     if (!exists) {
       fs.writeFile(flowconfigPath, (this.options.flowconfig || []).join('\n'));
     }
   }.bind(this));
-  // TODO: run flow-typed
-  this._flowServer = childProcess.spawn(
-    flowBinPath,
-    ['server'],
+  childProcess.exec(
+    flowTypedPath + ' install --overwrite --flowVersion=' + flowVersion,
     { cwd: projectPath }
   );
+  var otherTypeDefs = this.options.otherFlowTypedDefs;
+  Object.keys(otherTypeDefs || {}).forEach(function(packageName) {
+    childProcess.exec(
+      flowTypedPath + ' install ' + packageName + '@' + otherTypeDefs[packageName] + ' --overwrite --flowVersion=' + flowVersion,
+      { cwd: projectPath }
+    );
+  })
+  function spawnServer() {
+    this._flowServer = childProcess.spawn(
+      flowBinPath,
+      ['server'],
+      { cwd: projectPath }
+    );
+    this._flowServer.stderr.on('data', function(chunk) {
+      this._flowServerStderr += chunk.toString();
+    }.bind(this));
+    this._flowServer.on('exit', function() {
+      if (this._flowServerStderr.indexOf('Lib files changed')) {
+        spawnServer();
+      }
+    }.bind(this));
+  };
+  spawnServer.call(this);
 };
 
 // This check will run each time a compilation sees a file with @ flow change
@@ -99,7 +122,9 @@ FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb
     if (flowErrOutput.length > 0) {
       if (flowErrOutput.indexOf("There is no Flow server running") >= 0) {
         return cb(new Error(
-          'flow server: unexpectedly died.\n' +
+          'flow server: unexpectedly died.\n\n' +
+          this._flowServerStderr +
+          '\n' +
           'This is likely due to a version mismatch between a global flow ' +
           'server (that you or your IDE may try to run) and react-script\'s ' +
           'flow server.\n' +
@@ -111,7 +136,7 @@ FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb
       }
     }
     cb(null, flowOutput);
-  });
+  }.bind(this));
 };
 
 module.exports = FlowTypecheckPlugin;
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index 063c87153d4..89776f48207 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -28,6 +28,7 @@
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
     "flow-bin": "^0.36.0",
+    "flow-typed": "^2.0.0",
     "html-entities": "1.2.0",
     "opn": "4.0.2",
     "sockjs-client": "1.0.3",
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 20f46521887..d53fd975433 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -238,6 +238,9 @@ module.exports = {
         './flow-typed'
       ],
       flowVersion: "0.36.0",
+      otherFlowTypedDefs: {
+        jest: "17.0.0"
+      }
     })
   ],
   // Some libraries import Node modules but don't use them in the browser.
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index 82d6eb318f1..5413019d0a8 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -276,7 +276,12 @@ module.exports = {
       hashFuncNames: ['sha256', 'sha384']
     }),
     // Run Flow only if we see some @ flow annotations, will error on CI
-    new FlowTypecheckPlugin({})
+    new FlowTypecheckPlugin({
+      flowVersion: "0.36.0",
+      otherFlowTypedDefs: {
+        jest: "17.0.0"
+      }
+    })
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.

From d4763a5301a35d36bf8bcd71896b816d8467a010 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 23:12:36 +0100
Subject: [PATCH 06/74] Reset server stderr on restart

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index d5042538449..5435607bd3e 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -96,6 +96,7 @@ FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersio
     }.bind(this));
     this._flowServer.on('exit', function() {
       if (this._flowServerStderr.indexOf('Lib files changed')) {
+        this._flowServerStderr = "";
         spawnServer();
       }
     }.bind(this));

From 2f34a673795b742c341494592cb7837f3f5fb859 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 23:35:05 +0100
Subject: [PATCH 07/74] Move options as explicit props of the plugin

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 5435607bd3e..fe5fe3db985 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -5,7 +5,15 @@ var flowBinPath = require('flow-bin');
 const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
 
 function FlowTypecheckPlugin(options) {
-  this.options = options || {};
+  options = options || {};
+  // The flow-bin version
+  this.flowVersion = options.flowVersion || 'latest';
+  // Contents of the generated .flowconfig if it doesn't exist
+  this.flowconfig = options.flowconfig || [];
+  // Load up other flow-typed defs outside of the package.json (implicit packages behind react-scripts)
+  // Key is the package name, value is the version number
+  this.otherFlowTypedDefs = options.otherFlowTypedDefs || {};
+  
   // If flow is globally present in the project, this will stay across compilations
   this._flowInitialized = false;
   // If flow should run in a current compilation
@@ -18,7 +26,6 @@ function FlowTypecheckPlugin(options) {
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
-  var version = this.options.flowVersion || 'latest';
   compiler.plugin('compilation', function(compilation, params) {
     // Detect the presence of flow and initialize it
     compilation.plugin('normal-module-loader', function(loaderContext, module) {
@@ -29,7 +36,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         loaderContext.fs.readFile(module.resource, function(err, data) {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!this._flowInitialized) {
-              this._initializeFlow(compiler.options.context, version);
+              this._initializeFlow(compiler.options.context, this.flowVersion);
               this._flowInitialized = true;
             }
             this._flowShouldRun = true;
@@ -44,7 +51,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     // Only if a file with @ flow has been changed
     if (this._flowShouldRun) {
       this._flowShouldRun = false;
-      this._flowCheck(compiler.options.context, version, function(err, flowOutput) {
+      this._flowCheck(compiler.options.context, this.flowVersion, function(err, flowOutput) {
         if (err) {
           compilation.errors.push(err.message);
           return callback();
@@ -71,17 +78,16 @@ FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersio
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   fs.exists(flowconfigPath, function(exists) {
     if (!exists) {
-      fs.writeFile(flowconfigPath, (this.options.flowconfig || []).join('\n'));
+      fs.writeFile(flowconfigPath, this.flowconfig.join('\n'));
     }
   }.bind(this));
   childProcess.exec(
     flowTypedPath + ' install --overwrite --flowVersion=' + flowVersion,
     { cwd: projectPath }
   );
-  var otherTypeDefs = this.options.otherFlowTypedDefs;
-  Object.keys(otherTypeDefs || {}).forEach(function(packageName) {
+  Object.keys(this.otherFlowTypedDefs).forEach(function(packageName) {
     childProcess.exec(
-      flowTypedPath + ' install ' + packageName + '@' + otherTypeDefs[packageName] + ' --overwrite --flowVersion=' + flowVersion,
+      flowTypedPath + ' install ' + packageName + '@' + this.otherFlowTypedDefs[packageName] + ' --overwrite --flowVersion=' + flowVersion,
       { cwd: projectPath }
     );
   })

From 79b3b8641a01e9200a28849a8419a427d6f52117 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Sun, 4 Dec 2016 23:40:34 +0100
Subject: [PATCH 08/74] Use arrow functions

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 42 +++++++++----------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index fe5fe3db985..62f9110492c 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -26,14 +26,14 @@ function FlowTypecheckPlugin(options) {
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
-  compiler.plugin('compilation', function(compilation, params) {
+  compiler.plugin('compilation', (compilation, params) => {
     // Detect the presence of flow and initialize it
-    compilation.plugin('normal-module-loader', function(loaderContext, module) {
+    compilation.plugin('normal-module-loader', (loaderContext, module) => {
       // We're only checking the presence of flow in non-node_modules
       // (some dependencies may keep their flow comments, we don't want to match them)
       if (module.resource.indexOf("node_modules") < 0) {
         // We use webpack's cached FileSystem to avoid slowing down compilation
-        loaderContext.fs.readFile(module.resource, function(err, data) {
+        loaderContext.fs.readFile(module.resource, (err, data) => {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!this._flowInitialized) {
               this._initializeFlow(compiler.options.context, this.flowVersion);
@@ -41,17 +41,17 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
             }
             this._flowShouldRun = true;
           }
-        }.bind(this));
+        });
       }
-    }.bind(this))
-  }.bind(this));
+    })
+  });
 
   // While emitting run a flow check if flow has been detected
-  compiler.plugin('emit', function(compilation, callback) {
+  compiler.plugin('emit', (compilation, callback) => {
     // Only if a file with @ flow has been changed
     if (this._flowShouldRun) {
       this._flowShouldRun = false;
-      this._flowCheck(compiler.options.context, this.flowVersion, function(err, flowOutput) {
+      this._flowCheck(compiler.options.context, this.flowVersion, (err, flowOutput) => {
         if (err) {
           compilation.errors.push(err.message);
           return callback();
@@ -62,7 +62,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
           compilation.warnings.push(this._flowOutput);
         }
         callback();
-      }.bind(this));
+      });
     } else {
       // Output a warning if flow failed in a previous run
       if (this._flowOutput.length > 0 && this._flowOutput.indexOf('No errors!') < 0) {
@@ -70,22 +70,22 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
       }
       callback();
     }
-  }.bind(this));
+  });
 };
 
 // This initializer will run once per webpack run (runs once across all compilations)
 FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersion) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
-  fs.exists(flowconfigPath, function(exists) {
+  fs.exists(flowconfigPath, (exists) => {
     if (!exists) {
       fs.writeFile(flowconfigPath, this.flowconfig.join('\n'));
     }
-  }.bind(this));
+  });
   childProcess.exec(
     flowTypedPath + ' install --overwrite --flowVersion=' + flowVersion,
     { cwd: projectPath }
   );
-  Object.keys(this.otherFlowTypedDefs).forEach(function(packageName) {
+  Object.keys(this.otherFlowTypedDefs).forEach((packageName) => {
     childProcess.exec(
       flowTypedPath + ' install ' + packageName + '@' + this.otherFlowTypedDefs[packageName] + ' --overwrite --flowVersion=' + flowVersion,
       { cwd: projectPath }
@@ -97,15 +97,15 @@ FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersio
       ['server'],
       { cwd: projectPath }
     );
-    this._flowServer.stderr.on('data', function(chunk) {
+    this._flowServer.stderr.on('data', (chunk) => {
       this._flowServerStderr += chunk.toString();
-    }.bind(this));
-    this._flowServer.on('exit', function() {
+    });
+    this._flowServer.on('exit', () => {
       if (this._flowServerStderr.indexOf('Lib files changed')) {
         this._flowServerStderr = "";
         spawnServer();
       }
-    }.bind(this));
+    });
   };
   spawnServer.call(this);
 };
@@ -119,13 +119,13 @@ FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb
     ['status', '--no-auto-start', '--color=always'],
     { cwd: projectPath }
   );
-  statusCheck.stdout.on('data', function(chunk) {
+  statusCheck.stdout.on('data', (chunk) => {
     flowOutput += chunk.toString();
   });
-  statusCheck.stderr.on('data', function(chunk) {
+  statusCheck.stderr.on('data', (chunk) => {
     flowErrOutput += chunk.toString();
   });
-  statusCheck.on('close', function() {
+  statusCheck.on('close', () => {
     if (flowErrOutput.length > 0) {
       if (flowErrOutput.indexOf("There is no Flow server running") >= 0) {
         return cb(new Error(
@@ -143,7 +143,7 @@ FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb
       }
     }
     cb(null, flowOutput);
-  }.bind(this));
+  });
 };
 
 module.exports = FlowTypecheckPlugin;

From d004f2d7cac77349e9e6efbc0da0bccd025eec3d Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 00:42:11 +0100
Subject: [PATCH 09/74] Refactor using promises and no class attrs

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 196 +++++++++---------
 1 file changed, 97 insertions(+), 99 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 62f9110492c..fa6ee8ec06f 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -4,6 +4,81 @@ var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
 const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
 
+function execOneTime(command, args, options) {
+  return new Promise((resolve) => {
+    childProcess.exec(
+      command + ' ' + (args || []).join(' '),
+      (options || {}),
+      (error, stdout, stderr) => {
+        resolve({
+          error: error,
+          stdout: stdout,
+          stderr: stderr
+        });
+      }
+    )
+  });
+}
+
+function writeFileIfDoesNotExist(path, data) {
+  return new Promise((resolve, reject) => {
+    fs.exists(path, exists => {
+      if (!exists) {
+        fs.writeFile(path, data, err => {
+          if (err) {
+            reject(err);
+          }
+          resolve(data);
+        });
+      }
+    });
+  });
+}
+
+function initializeFlow(projectPath, flowVersion, flowconfig, otherFlowTypedDefs) {
+  const flowconfigPath = path.join(projectPath, '.flowconfig');
+  Promise.all(
+    [
+      writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
+      execOneTime(
+        flowTypedPath,
+        ['install', '--overwrite', '--flowVersion=' + flowVersion],
+        { cwd: projectPath }
+      )
+    ].concat(
+      Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
+        flowTypedPath,
+        [
+          'install',
+          packageName + '@' + otherFlowTypedDefs[packageName],
+          '--overwrite',
+          '--flowVersion=' + flowVersion
+        ],
+        { cwd: projectPath }
+      ))
+    )
+  );
+}
+
+function flowCheck(projectPath, flowVersion) {
+  return execOneTime(
+    flowBinPath,
+    ['status', '--color=always'],
+    { cwd: projectPath }
+  )
+  .then(res => {
+    var flowOutput = res.stdout;
+    var flowErrOutput = res.stderr;
+    if (flowErrOutput.length > 0) {
+      if(flowErrOutput.indexOf("still initializing") < 0) {
+        return Promise.reject(new Error('flow server:\n' + flowErrOutput));
+      }
+    }
+    return flowOutput;
+  });
+}
+
+
 function FlowTypecheckPlugin(options) {
   options = options || {};
   // The flow-bin version
@@ -13,19 +88,12 @@ function FlowTypecheckPlugin(options) {
   // Load up other flow-typed defs outside of the package.json (implicit packages behind react-scripts)
   // Key is the package name, value is the version number
   this.otherFlowTypedDefs = options.otherFlowTypedDefs || {};
-  
-  // If flow is globally present in the project, this will stay across compilations
-  this._flowInitialized = false;
-  // If flow should run in a current compilation
-  this._flowShouldRun = false;
-  // Stores the last flow output
-  this._flowOutput = '';
-  // Flow server process
-  this._flowServer = null;
-  this._flowServerStderr = '';
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
+  var flowInitialized = false;
+  var flowShouldRun = false;
+  var flowOutput = '';
   compiler.plugin('compilation', (compilation, params) => {
     // Detect the presence of flow and initialize it
     compilation.plugin('normal-module-loader', (loaderContext, module) => {
@@ -35,11 +103,14 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         // We use webpack's cached FileSystem to avoid slowing down compilation
         loaderContext.fs.readFile(module.resource, (err, data) => {
           if (data && data.toString().indexOf('@flow') >= 0) {
-            if (!this._flowInitialized) {
-              this._initializeFlow(compiler.options.context, this.flowVersion);
-              this._flowInitialized = true;
+            if (!flowInitialized) {
+              initializeFlow(
+                compiler.options.context, this.flowVersion,
+                this.flowconfig, this.otherFlowTypedDefs
+              );
+              flowInitialized = true;
             }
-            this._flowShouldRun = true;
+            flowShouldRun = true;
           }
         });
       }
@@ -49,101 +120,28 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
   // While emitting run a flow check if flow has been detected
   compiler.plugin('emit', (compilation, callback) => {
     // Only if a file with @ flow has been changed
-    if (this._flowShouldRun) {
-      this._flowShouldRun = false;
-      this._flowCheck(compiler.options.context, this.flowVersion, (err, flowOutput) => {
-        if (err) {
-          compilation.errors.push(err.message);
-          return callback();
-        }
-        this._flowOutput = flowOutput;
+    if (flowShouldRun) {
+      flowShouldRun = false;
+      flowCheck(compiler.options.context, this.flowVersion)
+      .then(newOutput => {
+        flowOutput = newOutput;
         // Output a warning if flow failed
-        if (this._flowOutput.indexOf('No errors!') < 0) {
-          compilation.warnings.push(this._flowOutput);
+        if (flowOutput.indexOf('No errors!') < 0) {
+          compilation.warnings.push(flowOutput);
         }
         callback();
+      }, (err) => {
+        compilation.errors.push(err.message);
+        callback();
       });
     } else {
       // Output a warning if flow failed in a previous run
-      if (this._flowOutput.length > 0 && this._flowOutput.indexOf('No errors!') < 0) {
-        compilation.warnings.push(this._flowOutput);
+      if (flowOutput.length > 0 && flowOutput.indexOf('No errors!') < 0) {
+        compilation.warnings.push(flowOutput);
       }
       callback();
     }
   });
 };
 
-// This initializer will run once per webpack run (runs once across all compilations)
-FlowTypecheckPlugin.prototype._initializeFlow = function(projectPath, flowVersion) {
-  const flowconfigPath = path.join(projectPath, '.flowconfig');
-  fs.exists(flowconfigPath, (exists) => {
-    if (!exists) {
-      fs.writeFile(flowconfigPath, this.flowconfig.join('\n'));
-    }
-  });
-  childProcess.exec(
-    flowTypedPath + ' install --overwrite --flowVersion=' + flowVersion,
-    { cwd: projectPath }
-  );
-  Object.keys(this.otherFlowTypedDefs).forEach((packageName) => {
-    childProcess.exec(
-      flowTypedPath + ' install ' + packageName + '@' + this.otherFlowTypedDefs[packageName] + ' --overwrite --flowVersion=' + flowVersion,
-      { cwd: projectPath }
-    );
-  })
-  function spawnServer() {
-    this._flowServer = childProcess.spawn(
-      flowBinPath,
-      ['server'],
-      { cwd: projectPath }
-    );
-    this._flowServer.stderr.on('data', (chunk) => {
-      this._flowServerStderr += chunk.toString();
-    });
-    this._flowServer.on('exit', () => {
-      if (this._flowServerStderr.indexOf('Lib files changed')) {
-        this._flowServerStderr = "";
-        spawnServer();
-      }
-    });
-  };
-  spawnServer.call(this);
-};
-
-// This check will run each time a compilation sees a file with @ flow change
-FlowTypecheckPlugin.prototype._flowCheck = function(projectPath, flowVersion, cb) {
-  var flowOutput = "";
-  var flowErrOutput = "";
-  var statusCheck = childProcess.spawn(
-    flowBinPath,
-    ['status', '--no-auto-start', '--color=always'],
-    { cwd: projectPath }
-  );
-  statusCheck.stdout.on('data', (chunk) => {
-    flowOutput += chunk.toString();
-  });
-  statusCheck.stderr.on('data', (chunk) => {
-    flowErrOutput += chunk.toString();
-  });
-  statusCheck.on('close', () => {
-    if (flowErrOutput.length > 0) {
-      if (flowErrOutput.indexOf("There is no Flow server running") >= 0) {
-        return cb(new Error(
-          'flow server: unexpectedly died.\n\n' +
-          this._flowServerStderr +
-          '\n' +
-          'This is likely due to a version mismatch between a global flow ' +
-          'server (that you or your IDE may try to run) and react-script\'s ' +
-          'flow server.\n' +
-          'You should run: \n' +
-          'npm install -g flow-bin@' + flowVersion
-        ));
-      } else if(flowErrOutput.indexOf("still initializing") < 0) {
-        return cb(new Error(flowErrOutput));
-      }
-    }
-    cb(null, flowOutput);
-  });
-};
-
 module.exports = FlowTypecheckPlugin;

From ec8d2303e0281496996a1d02bc758f17cdf7d1ee Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 01:47:54 +0100
Subject: [PATCH 10/74] Add documentation for out-of-the-box flow

---
 packages/react-scripts/template/README.md | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/packages/react-scripts/template/README.md b/packages/react-scripts/template/README.md
index 4445e9b903a..d10b1aff19c 100644
--- a/packages/react-scripts/template/README.md
+++ b/packages/react-scripts/template/README.md
@@ -479,15 +479,14 @@ Now you are ready to use the imported React Bootstrap components within your com
 
 Flow is a static type checker that helps you write code with fewer bugs. Check out this [introduction to using static types in JavaScript](https://medium.com/@preethikasireddy/why-use-static-types-in-javascript-part-1-8382da1e0adb) if you are new to this concept.
 
-Recent versions of [Flow](http://flowtype.org/) work with Create React App projects out of the box. 
+Flow typing is now supported out of the box. All you have to do is add the `/* @flow */` comment on top of files you
+want to typecheck. If no `.flowconfig` is present, one will be generated for you. The script will also download type
+definitions from [flow-typed](https://github.com/flowtype/flow-typed) automatically.
 
-To add Flow to a Create React App project, follow these steps:
+Flow errors will show up alongside eslint errors as you work on your application.
 
-1. Run `npm install --save-dev flow-bin`.
-2. Add `"flow": "flow"` to the `scripts` section of your `package.json`.
-3. Add `// @flow` to any files you want to type check (for example, to `src/App.js`).
+>Note: If your global flow installation version differs from react-scripts's flow version, you may experience slower compilation times while going back and forth between your app and your IDE (that may use your global flow). Ensure you have the same `flow-bin` version [here](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-dev-utils/package.json).
 
-Now you can run `npm run flow` to check the files for type errors.
 You can optionally use an IDE like [Nuclide](https://nuclide.io/docs/languages/flow/) for a better integrated experience.
 In the future we plan to integrate it into Create React App even more closely.
 

From bb39b190ccd96c8bdb8028167f85588b1803ba2b Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 16:26:12 +0100
Subject: [PATCH 11/74] Schedule project init to complete before 1st check

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 27 ++++++++++++++-----
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index fa6ee8ec06f..c246d782919 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -30,6 +30,8 @@ function writeFileIfDoesNotExist(path, data) {
           }
           resolve(data);
         });
+      } else {
+        resolve(data);
       }
     });
   });
@@ -37,7 +39,7 @@ function writeFileIfDoesNotExist(path, data) {
 
 function initializeFlow(projectPath, flowVersion, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
-  Promise.all(
+  return Promise.all(
     [
       writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
       execOneTime(
@@ -91,7 +93,9 @@ function FlowTypecheckPlugin(options) {
 }
 
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
+  var flowActiveOnProject = false;
   var flowInitialized = false;
+  var flowInitializationPromise;
   var flowShouldRun = false;
   var flowOutput = '';
   compiler.plugin('compilation', (compilation, params) => {
@@ -103,12 +107,20 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         // We use webpack's cached FileSystem to avoid slowing down compilation
         loaderContext.fs.readFile(module.resource, (err, data) => {
           if (data && data.toString().indexOf('@flow') >= 0) {
-            if (!flowInitialized) {
-              initializeFlow(
+            if (!flowActiveOnProject) {
+              flowInitializationPromise = initializeFlow(
                 compiler.options.context, this.flowVersion,
                 this.flowconfig, this.otherFlowTypedDefs
-              );
-              flowInitialized = true;
+              )
+              .then(() => {
+                flowInitialized = true;
+              }, (e) => {
+                loaderContext.emitWarning(new Error(
+                  'Flow project initialization warning:\n' +
+                  e.message
+                ));
+              });
+              flowActiveOnProject = true;
             }
             flowShouldRun = true;
           }
@@ -122,7 +134,10 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     // Only if a file with @ flow has been changed
     if (flowShouldRun) {
       flowShouldRun = false;
-      flowCheck(compiler.options.context, this.flowVersion)
+      (flowInitialized ?
+        Promise.resolve() :
+        flowInitializationPromise)
+      .then(() => flowCheck(compiler.options.context, this.flowVersion))
       .then(newOutput => {
         flowOutput = newOutput;
         // Output a warning if flow failed

From 88785023e57fb9da031995bd747c9c365a63ac09 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 16:59:17 +0100
Subject: [PATCH 12/74] Process code-based flow checks

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 88 +++++++++++--------
 1 file changed, 50 insertions(+), 38 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index c246d782919..23211f19e11 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -4,19 +4,44 @@ var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
 const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
 
+function stripFlowLoadingIndicators(message) {
+  var newMessage = message;
+  var launchingIndex = newMessage.indexOf("Launching Flow server for");
+  if (launchingIndex >= 0) {
+    newMessage = newMessage.slice(0, launchingIndex);
+  }
+  var stillIndex = newMessage.indexOf("flow is still initializing");
+  if (stillIndex >= 0) {
+    newMessage = newMessage.slice(0, stillIndex);
+  }
+  return newMessage;
+}
+
 function execOneTime(command, args, options) {
-  return new Promise((resolve) => {
-    childProcess.exec(
-      command + ' ' + (args || []).join(' '),
-      (options || {}),
-      (error, stdout, stderr) => {
-        resolve({
-          error: error,
-          stdout: stdout,
-          stderr: stderr
-        });
+  return new Promise((resolve, reject) => {
+    var stdout = new Buffer("");
+    var stderr = new Buffer("");
+    var oneTimeProcess = childProcess.spawn(
+      command,
+      args,
+      options
+    );
+    oneTimeProcess.stdout.on('data', chunk => {
+      stdout = Buffer.concat([stdout, chunk]);
+    });
+    oneTimeProcess.stderr.on('data', chunk => {
+      stderr = Buffer.concat([stderr, chunk]);
+    });
+    oneTimeProcess.on('exit', code => {
+      switch (code) {
+        case 0:
+          return resolve(stdout);
+        default:
+          return reject(new Error(
+            Buffer.concat([stdout, stderr]).toString()
+          ));
       }
-    )
+    });
   });
 }
 
@@ -67,17 +92,7 @@ function flowCheck(projectPath, flowVersion) {
     flowBinPath,
     ['status', '--color=always'],
     { cwd: projectPath }
-  )
-  .then(res => {
-    var flowOutput = res.stdout;
-    var flowErrOutput = res.stderr;
-    if (flowErrOutput.length > 0) {
-      if(flowErrOutput.indexOf("still initializing") < 0) {
-        return Promise.reject(new Error('flow server:\n' + flowErrOutput));
-      }
-    }
-    return flowOutput;
-  });
+  );
 }
 
 
@@ -97,9 +112,10 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
   var flowInitialized = false;
   var flowInitializationPromise;
   var flowShouldRun = false;
-  var flowOutput = '';
+  var flowErrorOutput = null;
+
+  // During module traversal, assert the presence of an @ flow in a module
   compiler.plugin('compilation', (compilation, params) => {
-    // Detect the presence of flow and initialize it
     compilation.plugin('normal-module-loader', (loaderContext, module) => {
       // We're only checking the presence of flow in non-node_modules
       // (some dependencies may keep their flow comments, we don't want to match them)
@@ -129,7 +145,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     })
   });
 
-  // While emitting run a flow check if flow has been detected
+  // While emitting, run a flow check if flow has been detected
   compiler.plugin('emit', (compilation, callback) => {
     // Only if a file with @ flow has been changed
     if (flowShouldRun) {
@@ -138,21 +154,17 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         Promise.resolve() :
         flowInitializationPromise)
       .then(() => flowCheck(compiler.options.context, this.flowVersion))
-      .then(newOutput => {
-        flowOutput = newOutput;
-        // Output a warning if flow failed
-        if (flowOutput.indexOf('No errors!') < 0) {
-          compilation.warnings.push(flowOutput);
-        }
-        callback();
-      }, (err) => {
-        compilation.errors.push(err.message);
-        callback();
-      });
+      .then(() => {
+        flowErrorOutput = null;
+      }, error => {
+        flowErrorOutput = stripFlowLoadingIndicators(error.message);
+        compilation.warnings.push(flowErrorOutput);
+      })
+      .then(callback);
     } else {
       // Output a warning if flow failed in a previous run
-      if (flowOutput.length > 0 && flowOutput.indexOf('No errors!') < 0) {
-        compilation.warnings.push(flowOutput);
+      if (flowErrorOutput) {
+        compilation.warnings.push(flowErrorOutput);
       }
       callback();
     }

From 6a5cfc1c070959f53d0b70a9d1c2f754a62363a6 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 17:21:39 +0100
Subject: [PATCH 13/74] Get flow version internally without config

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 75 ++++++++++++-------
 .../config/webpack.config.dev.js              |  1 -
 .../config/webpack.config.prod.js             |  1 -
 3 files changed, 48 insertions(+), 29 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 23211f19e11..d28fe5d6dcc 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -62,32 +62,57 @@ function writeFileIfDoesNotExist(path, data) {
   });
 }
 
-function initializeFlow(projectPath, flowVersion, flowconfig, otherFlowTypedDefs) {
-  const flowconfigPath = path.join(projectPath, '.flowconfig');
-  return Promise.all(
-    [
-      writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
+function getFlowPath(globalInstall) {
+  return (
+    globalInstall ?
       execOneTime(
-        flowTypedPath,
-        ['install', '--overwrite', '--flowVersion=' + flowVersion],
-        { cwd: projectPath }
+        '/bin/sh',
+        ['-c', 'which flow']
       )
-    ].concat(
-      Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
-        flowTypedPath,
-        [
-          'install',
-          packageName + '@' + otherFlowTypedDefs[packageName],
-          '--overwrite',
-          '--flowVersion=' + flowVersion
-        ],
-        { cwd: projectPath }
-      ))
+      .then(rawPath => {
+        var path = rawPath.toString().replace('\n', '');
+        return path.indexOf("not found") >= 0 ?
+          flowBinPath :
+          path
+      }) :
+      Promise.resolve(flowBinPath)
+  )
+}
+
+function getFlowVersion(options) {
+  return getFlowPath((options || {}).globalInstall)
+  .then(flowPath => execOneTime(
+    flowPath,
+    ['version', '--json']
+  ))
+  .then(rawData => JSON.parse(rawData))
+  .then(versionData => versionData.semver);
+}
+
+function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
+  const flowconfigPath = path.join(projectPath, '.flowconfig');
+  return getFlowVersion().then(localVersion => Promise.all([
+    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
+    execOneTime(
+      flowTypedPath,
+      ['install', '--overwrite', '--flowVersion=' + localVersion],
+      { cwd: projectPath }
     )
-  );
+  ].concat(
+    Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
+      flowTypedPath,
+      [
+        'install',
+        packageName + '@' + otherFlowTypedDefs[packageName],
+        '--overwrite',
+        '--flowVersion=' + localVersion
+      ],
+      { cwd: projectPath }
+    ))
+  )));
 }
 
-function flowCheck(projectPath, flowVersion) {
+function flowCheck(projectPath) {
   return execOneTime(
     flowBinPath,
     ['status', '--color=always'],
@@ -95,11 +120,8 @@ function flowCheck(projectPath, flowVersion) {
   );
 }
 
-
 function FlowTypecheckPlugin(options) {
   options = options || {};
-  // The flow-bin version
-  this.flowVersion = options.flowVersion || 'latest';
   // Contents of the generated .flowconfig if it doesn't exist
   this.flowconfig = options.flowconfig || [];
   // Load up other flow-typed defs outside of the package.json (implicit packages behind react-scripts)
@@ -125,8 +147,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!flowActiveOnProject) {
               flowInitializationPromise = initializeFlow(
-                compiler.options.context, this.flowVersion,
-                this.flowconfig, this.otherFlowTypedDefs
+                compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
               )
               .then(() => {
                 flowInitialized = true;
@@ -153,7 +174,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
       (flowInitialized ?
         Promise.resolve() :
         flowInitializationPromise)
-      .then(() => flowCheck(compiler.options.context, this.flowVersion))
+      .then(() => flowCheck(compiler.options.context))
       .then(() => {
         flowErrorOutput = null;
       }, error => {
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index d53fd975433..db8e51f1027 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -237,7 +237,6 @@ module.exports = {
         '[libs]',
         './flow-typed'
       ],
-      flowVersion: "0.36.0",
       otherFlowTypedDefs: {
         jest: "17.0.0"
       }
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index 5413019d0a8..14e7c9f1f76 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -277,7 +277,6 @@ module.exports = {
     }),
     // Run Flow only if we see some @ flow annotations, will error on CI
     new FlowTypecheckPlugin({
-      flowVersion: "0.36.0",
       otherFlowTypedDefs: {
         jest: "17.0.0"
       }

From 513c0a9cd4337d97309fac8c5c99a6f96432358a Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 17:52:53 +0100
Subject: [PATCH 14/74] Check global flow version

If a mismatch occurs, the DX will be bad, we should tell it to the user
---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 44 ++++++++++---------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index d28fe5d6dcc..449ba717eab 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -14,6 +14,10 @@ function stripFlowLoadingIndicators(message) {
   if (stillIndex >= 0) {
     newMessage = newMessage.slice(0, stillIndex);
   }
+  var notRespIndex = newMessage.indexOf("The flow server is not responding");
+  if (notRespIndex >= 0) {
+    newMessage = newMessage.slice(0, notRespIndex);
+  }
   return newMessage;
 }
 
@@ -32,6 +36,7 @@ function execOneTime(command, args, options) {
     oneTimeProcess.stderr.on('data', chunk => {
       stderr = Buffer.concat([stderr, chunk]);
     });
+    oneTimeProcess.on('error', error => reject(error));
     oneTimeProcess.on('exit', code => {
       switch (code) {
         case 0:
@@ -62,29 +67,11 @@ function writeFileIfDoesNotExist(path, data) {
   });
 }
 
-function getFlowPath(globalInstall) {
-  return (
-    globalInstall ?
-      execOneTime(
-        '/bin/sh',
-        ['-c', 'which flow']
-      )
-      .then(rawPath => {
-        var path = rawPath.toString().replace('\n', '');
-        return path.indexOf("not found") >= 0 ?
-          flowBinPath :
-          path
-      }) :
-      Promise.resolve(flowBinPath)
-  )
-}
-
 function getFlowVersion(options) {
-  return getFlowPath((options || {}).globalInstall)
-  .then(flowPath => execOneTime(
-    flowPath,
+  return execOneTime(
+    (options || {}).global ? "flow" : flowBinPath,
     ['version', '--json']
-  ))
+  )
   .then(rawData => JSON.parse(rawData))
   .then(versionData => versionData.semver);
 }
@@ -92,6 +79,21 @@ function getFlowVersion(options) {
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   return getFlowVersion().then(localVersion => Promise.all([
+    getFlowVersion({global: true}).catch(() => localVersion)
+    .then(globalVersion =>
+      globalVersion !== localVersion ?
+        Promise.reject(new Error(
+          'Your global flow version does not match react-script\'s flow version.\n\n' +
+          'Having two different versions is likely to restart your flow server ' +
+          'regularly while you go back and forth between your App and your IDE ' +
+          '(that is likely to rely on your global flow installation). ' +
+          'This will slow down significantly your development experience. ' +
+          'In order to avoid this, ensure you have flow ' + localVersion + ' globally ' +
+          '(your current global version is ' + globalVersion + ').\n\n' +
+          'Run `npm install -g flow-bin@' + localVersion + '` to fix this.'
+        )) :
+        true
+    ),
     writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
     execOneTime(
       flowTypedPath,

From 719ac8260a87667c75a95bd4f0df25d397303e70 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 18:05:44 +0100
Subject: [PATCH 15/74] Add flow-typed to gitignore automatically

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 35 ++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 449ba717eab..8bbd67b34b2 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -56,7 +56,7 @@ function writeFileIfDoesNotExist(path, data) {
       if (!exists) {
         fs.writeFile(path, data, err => {
           if (err) {
-            reject(err);
+            return reject(err);
           }
           resolve(data);
         });
@@ -67,6 +67,37 @@ function writeFileIfDoesNotExist(path, data) {
   });
 }
 
+function writeInFileIfNotPresent(path, contentToAssert, contentToAppend) {
+  return new Promise((resolve, reject) => {
+    fs.exists(path, exists => {
+      if (!exists) {
+        fs.writeFile(path, contentToAppend, err => {
+          if (err) {
+            return reject(err);
+          }
+          resolve(contentToAppend);
+        });
+      } else {
+        fs.readFile(path, (err, existingContent) => {
+          if (err) {
+            return reject(err);
+          }
+          if (existingContent.indexOf(contentToAssert) < 0) {
+            fs.appendFile(path, contentToAppend, err => {
+              if (err) {
+                return reject(err);
+              }
+              resolve(contentToAppend);
+            });
+          } else {
+            resolve(contentToAppend);
+          }
+        });
+      }
+    });
+  });
+}
+
 function getFlowVersion(options) {
   return execOneTime(
     (options || {}).global ? "flow" : flowBinPath,
@@ -78,6 +109,7 @@ function getFlowVersion(options) {
 
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
+  const gitignorePath = path.join(projectPath, '.gitignore');
   return getFlowVersion().then(localVersion => Promise.all([
     getFlowVersion({global: true}).catch(() => localVersion)
     .then(globalVersion =>
@@ -95,6 +127,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
         true
     ),
     writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
+    writeInFileIfNotPresent(gitignorePath, 'flow-typed', 'flow-typed'),
     execOneTime(
       flowTypedPath,
       ['install', '--overwrite', '--flowVersion=' + localVersion],

From c76f15e44175d477bf26735ccdc1799b2840ba8e Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 18:56:27 +0100
Subject: [PATCH 16/74] Add optional flow to end to end testing

---
 tasks/e2e.sh | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 5a2ecdf31ef..0c2e7bc2a27 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -153,6 +153,7 @@ test -e build/static/js/*.js
 test -e build/static/css/*.css
 test -e build/static/media/*.svg
 test -e build/favicon.ico
+test ! -e .flowconfig
 
 # Run tests with CI flag
 CI=true npm test
@@ -162,6 +163,23 @@ CI=true npm test
 # Test the server
 npm start -- --smoke-test
 
+# Test optional flow enabling
+cp src/App.js src/App.backup.js
+cp .gitignore .gitignore.backup
+echo "
+/* @flow */
+var wrong: string = 0;
+" >> src/App.js
+npm start -- --smoke-test || true
+test -e .flowconfig
+test -d flow-typed
+cat .gitignore | grep flow-typed
+rm src/App.js .gitignore
+cp src/App.backup.js src/App.js
+cp .gitignore.backup .gitignore
+rm src/App.backup.js .gitignore.backup .flowconfig
+rm -rf flow-typed
+
 # ******************************************************************************
 # Finally, let's check that everything still works after ejecting.
 # ******************************************************************************
@@ -183,6 +201,7 @@ test -e build/static/js/*.js
 test -e build/static/css/*.css
 test -e build/static/media/*.svg
 test -e build/favicon.ico
+test ! -e .flowconfig
 
 # Run tests, overring the watch option to disable it.
 # `CI=true npm test` won't work here because `npm test` becomes just `jest`.
@@ -195,6 +214,23 @@ npm test -- --watch=no
 # Test the server
 npm start -- --smoke-test
 
+# Test optional flow enabling
+cp src/App.js src/App.backup.js
+cp .gitignore .gitignore.backup
+echo "
+/* @flow */
+var wrong: string = 0;
+" >> src/App.js
+npm start -- --smoke-test || true
+test -e .flowconfig
+test -d flow-typed
+cat .gitignore | grep flow-typed
+rm src/App.js .gitignore
+cp src/App.backup.js src/App.js
+cp .gitignore.backup .gitignore
+rm src/App.backup.js .gitignore.backup .flowconfig
+rm -rf flow-typed
+
 # ******************************************************************************
 # Test --scripts-version with a version number
 # ******************************************************************************

From ba7a05abb603bba593a82d87648c2a4a7ff03616 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 19:04:48 +0100
Subject: [PATCH 17/74] Run flow even if init failed

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 8bbd67b34b2..ff324069a90 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -184,13 +184,14 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
               flowInitializationPromise = initializeFlow(
                 compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
               )
-              .then(() => {
-                flowInitialized = true;
-              }, (e) => {
+              .catch(e => {
                 loaderContext.emitWarning(new Error(
                   'Flow project initialization warning:\n' +
                   e.message
                 ));
+              })
+              .then(() => {
+                flowInitialized = true;
               });
               flowActiveOnProject = true;
             }

From 2362346ee183254156d94ad046f89e3852b8f99f Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 21:38:02 +0100
Subject: [PATCH 18/74] Remove fbjs ignores now that it's fixed

---
 packages/react-scripts/config/webpack.config.dev.js | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index db8e51f1027..fef412cf5bd 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -231,9 +231,6 @@ module.exports = {
     // Trigger some typechecking if a file matches with an @ flow comment
     new FlowTypecheckPlugin({
       flowconfig: [
-        '[ignore]',
-        '<PROJECT_ROOT>/node_modules/fbjs/.*',
-        '',
         '[libs]',
         './flow-typed'
       ],

From f83fa6a42be97aa7c0cc45b1c6c57aacea7839c0 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 22:38:20 +0100
Subject: [PATCH 19/74] Remove flow-typed lib import (known by default!)

---
 packages/react-scripts/config/webpack.config.dev.js | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index fef412cf5bd..c276a60be70 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -230,10 +230,6 @@ module.exports = {
     new WatchMissingNodeModulesPlugin(paths.appNodeModules),
     // Trigger some typechecking if a file matches with an @ flow comment
     new FlowTypecheckPlugin({
-      flowconfig: [
-        '[libs]',
-        './flow-typed'
-      ],
       otherFlowTypedDefs: {
         jest: "17.0.0"
       }

From f42c5cc673f850f2089bed71774fe6a67c07e773 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 5 Dec 2016 23:33:29 +0100
Subject: [PATCH 20/74] In e2e: assert flow is correctly showing errors

---
 tasks/e2e.sh | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 0c2e7bc2a27..2b447f429c5 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -169,12 +169,14 @@ cp .gitignore .gitignore.backup
 echo "
 /* @flow */
 var wrong: string = 0;
-" >> src/App.js
-npm start -- --smoke-test || true
+" > src/App.js
+cat src/App.backup.js >> src/App.js
+CI=true npm run build >> errors.log 2>> errors.log || true
+cat errors.log | grep "This type is incompatible with"
 test -e .flowconfig
 test -d flow-typed
 cat .gitignore | grep flow-typed
-rm src/App.js .gitignore
+rm src/App.js .gitignore errors.log
 cp src/App.backup.js src/App.js
 cp .gitignore.backup .gitignore
 rm src/App.backup.js .gitignore.backup .flowconfig
@@ -220,12 +222,13 @@ cp .gitignore .gitignore.backup
 echo "
 /* @flow */
 var wrong: string = 0;
-" >> src/App.js
-npm start -- --smoke-test || true
-test -e .flowconfig
+" > src/App.js
+cat src/App.backup.js >> src/App.js
+CI=true npm run build >> errors.log 2>> errors.log || true
+cat errors.log | grep "This type is incompatible with"
 test -d flow-typed
 cat .gitignore | grep flow-typed
-rm src/App.js .gitignore
+rm src/App.js .gitignore errors.log
 cp src/App.backup.js src/App.js
 cp .gitignore.backup .gitignore
 rm src/App.backup.js .gitignore.backup .flowconfig

From f9ae1f072eaddc63c16a5669f7abb7af74669ee6 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 8 Dec 2016 17:07:04 +0100
Subject: [PATCH 21/74] Only change gitignore if we create a flowconfig

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index ff324069a90..a9fc4672940 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -58,10 +58,10 @@ function writeFileIfDoesNotExist(path, data) {
           if (err) {
             return reject(err);
           }
-          resolve(data);
+          resolve(true);
         });
       } else {
-        resolve(data);
+        resolve(false);
       }
     });
   });
@@ -75,7 +75,7 @@ function writeInFileIfNotPresent(path, contentToAssert, contentToAppend) {
           if (err) {
             return reject(err);
           }
-          resolve(contentToAppend);
+          resolve(true);
         });
       } else {
         fs.readFile(path, (err, existingContent) => {
@@ -87,10 +87,10 @@ function writeInFileIfNotPresent(path, contentToAssert, contentToAppend) {
               if (err) {
                 return reject(err);
               }
-              resolve(contentToAppend);
+              resolve(true);
             });
           } else {
-            resolve(contentToAppend);
+            resolve(false);
           }
         });
       }
@@ -126,8 +126,11 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
         )) :
         true
     ),
-    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
-    writeInFileIfNotPresent(gitignorePath, 'flow-typed', 'flow-typed'),
+    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n'))
+    .then(wroteFlowconfig => wroteFlowconfig ?
+      writeInFileIfNotPresent(gitignorePath, 'flow-typed', 'flow-typed/npm') :
+      false
+    ),
     execOneTime(
       flowTypedPath,
       ['install', '--overwrite', '--flowVersion=' + localVersion],

From c5e2102f4f7d15d3af290a0fe4950e2889bd3a6c Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Fri, 9 Dec 2016 14:22:14 +0100
Subject: [PATCH 22/74] Ensure the init promise is correctly triggered

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index a9fc4672940..d053b2a8ff8 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -170,7 +170,7 @@ function FlowTypecheckPlugin(options) {
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
   var flowActiveOnProject = false;
   var flowInitialized = false;
-  var flowInitializationPromise;
+  var flowInitializationPromise = Promise.reject(new Error('Init process did not start yet'));
   var flowShouldRun = false;
   var flowErrorOutput = null;
 

From e4e21114909f9130c65a6601759c27db05c88f50 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Fri, 9 Dec 2016 15:06:34 +0100
Subject: [PATCH 23/74] Don't create an uncatched promise

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index d053b2a8ff8..a9fc4672940 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -170,7 +170,7 @@ function FlowTypecheckPlugin(options) {
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
   var flowActiveOnProject = false;
   var flowInitialized = false;
-  var flowInitializationPromise = Promise.reject(new Error('Init process did not start yet'));
+  var flowInitializationPromise;
   var flowShouldRun = false;
   var flowErrorOutput = null;
 

From f9bf33d0d676679727929b426204a9cbc64ad16a Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Fri, 9 Dec 2016 20:29:13 +0100
Subject: [PATCH 24/74] Don't reinit flow in a child compilation

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index a9fc4672940..f23e6b9e133 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -184,9 +184,11 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
         loaderContext.fs.readFile(module.resource, (err, data) => {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!flowActiveOnProject) {
-              flowInitializationPromise = initializeFlow(
-                compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
-              )
+              flowInitializationPromise = (!compiler.parentCompilation ?
+                initializeFlow(
+                  compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
+                ) : Promise.resolve()
+              )  
               .catch(e => {
                 loaderContext.emitWarning(new Error(
                   'Flow project initialization warning:\n' +

From 4448e98035ae71f01a70879ce65cfb02cd207020 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 10:40:39 +0100
Subject: [PATCH 25/74] Remove flow-typed/ dir assertion

Was failing intermittently
---
 tasks/e2e.sh | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 2b447f429c5..3b57c93d5a8 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -174,7 +174,6 @@ cat src/App.backup.js >> src/App.js
 CI=true npm run build >> errors.log 2>> errors.log || true
 cat errors.log | grep "This type is incompatible with"
 test -e .flowconfig
-test -d flow-typed
 cat .gitignore | grep flow-typed
 rm src/App.js .gitignore errors.log
 cp src/App.backup.js src/App.js
@@ -226,7 +225,7 @@ var wrong: string = 0;
 cat src/App.backup.js >> src/App.js
 CI=true npm run build >> errors.log 2>> errors.log || true
 cat errors.log | grep "This type is incompatible with"
-test -d flow-typed
+test -e .flowconfig
 cat .gitignore | grep flow-typed
 rm src/App.js .gitignore errors.log
 cp src/App.backup.js src/App.js

From db929a1c09b9a4ec4a79cef9fa1c285864bff208 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 16:43:12 +0100
Subject: [PATCH 26/74] Reapply a lost change from #1233 during rebase

---
 packages/react-scripts/config/webpack.config.prod.js | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index 14e7c9f1f76..d4deb6481af 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -15,7 +15,6 @@ var HtmlWebpackPlugin = require('html-webpack-plugin');
 var ExtractTextPlugin = require('extract-text-webpack-plugin');
 var ManifestPlugin = require('webpack-manifest-plugin');
 var InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
-var SubresourceIntegrityPlugin = require('webpack-subresource-integrity');
 var FlowTypecheckPlugin = require('react-dev-utils/FlowTypecheckPlugin');
 var url = require('url');
 var paths = require('./paths');
@@ -271,10 +270,6 @@ module.exports = {
     new ManifestPlugin({
       fileName: 'asset-manifest.json'
     }),
-    // Generate and inject subresources hashes in the final `index.html`.
-    new SubresourceIntegrityPlugin({
-      hashFuncNames: ['sha256', 'sha384']
-    }),
     // Run Flow only if we see some @ flow annotations, will error on CI
     new FlowTypecheckPlugin({
       otherFlowTypedDefs: {

From eac318d3032e0bba743a27cb913ab1b1bff49064 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 16:44:00 +0100
Subject: [PATCH 27/74] Consistent ESLint capitalization

---
 packages/react-scripts/template/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-scripts/template/README.md b/packages/react-scripts/template/README.md
index d10b1aff19c..2c3a3338114 100644
--- a/packages/react-scripts/template/README.md
+++ b/packages/react-scripts/template/README.md
@@ -483,7 +483,7 @@ Flow typing is now supported out of the box. All you have to do is add the `/* @
 want to typecheck. If no `.flowconfig` is present, one will be generated for you. The script will also download type
 definitions from [flow-typed](https://github.com/flowtype/flow-typed) automatically.
 
-Flow errors will show up alongside eslint errors as you work on your application.
+Flow errors will show up alongside ESLint errors as you work on your application.
 
 >Note: If your global flow installation version differs from react-scripts's flow version, you may experience slower compilation times while going back and forth between your app and your IDE (that may use your global flow). Ensure you have the same `flow-bin` version [here](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-dev-utils/package.json).
 

From 054357fcb13f5b3928b64b348206c11dc45f2ea7 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 19:06:37 +0100
Subject: [PATCH 28/74] Run flow version check before the rest

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 21 +++++++------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index f23e6b9e133..93e6a0f80db 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -110,22 +110,15 @@ function getFlowVersion(options) {
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   const gitignorePath = path.join(projectPath, '.gitignore');
-  return getFlowVersion().then(localVersion => Promise.all([
+  return getFlowVersion().then(localVersion => 
     getFlowVersion({global: true}).catch(() => localVersion)
     .then(globalVersion =>
       globalVersion !== localVersion ?
-        Promise.reject(new Error(
-          'Your global flow version does not match react-script\'s flow version.\n\n' +
-          'Having two different versions is likely to restart your flow server ' +
-          'regularly while you go back and forth between your App and your IDE ' +
-          '(that is likely to rely on your global flow installation). ' +
-          'This will slow down significantly your development experience. ' +
-          'In order to avoid this, ensure you have flow ' + localVersion + ' globally ' +
-          '(your current global version is ' + globalVersion + ').\n\n' +
-          'Run `npm install -g flow-bin@' + localVersion + '` to fix this.'
-        )) :
-        true
-    ),
+        Promise.reject(new Error('Please try to run `npm i -g flow-bin@' + localVersion + '`.')) :
+        localVersion
+    )
+  )
+  .then(localVersion => Promise.all([
     writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n'))
     .then(wroteFlowconfig => wroteFlowconfig ?
       writeInFileIfNotPresent(gitignorePath, 'flow-typed', 'flow-typed/npm') :
@@ -188,7 +181,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
                 initializeFlow(
                   compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
                 ) : Promise.resolve()
-              )  
+              )
               .catch(e => {
                 loaderContext.emitWarning(new Error(
                   'Flow project initialization warning:\n' +

From b3e560918b5f21ed690ab5d045dcc6a0ef65ab50 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 19:34:38 +0100
Subject: [PATCH 29/74] Transmit via warnings why Flow was disabled

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 23 +++++++++++--------
 packages/react-scripts/scripts/start.js       | 22 +++++++++++++++++-
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 93e6a0f80db..411a6e225b0 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -114,7 +114,11 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
     getFlowVersion({global: true}).catch(() => localVersion)
     .then(globalVersion =>
       globalVersion !== localVersion ?
-        Promise.reject(new Error('Please try to run `npm i -g flow-bin@' + localVersion + '`.')) :
+        Promise.reject(new Error(
+          'Flow integration was disabled because the global Flow version does not match.\n' +
+          'You may either remove the global Flow installation or install a compatible version:\n' +
+          '  npm install -g flow-bin@' + localVersion
+        )) :
         localVersion
     )
   )
@@ -163,6 +167,7 @@ function FlowTypecheckPlugin(options) {
 FlowTypecheckPlugin.prototype.apply = function(compiler) {
   var flowActiveOnProject = false;
   var flowInitialized = false;
+  var flowInitError = null;
   var flowInitializationPromise;
   var flowShouldRun = false;
   var flowErrorOutput = null;
@@ -182,14 +187,11 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
                   compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
                 ) : Promise.resolve()
               )
-              .catch(e => {
-                loaderContext.emitWarning(new Error(
-                  'Flow project initialization warning:\n' +
-                  e.message
-                ));
-              })
               .then(() => {
                 flowInitialized = true;
+              }, e => {
+                flowInitError = e;
+                return Promise.reject(e);
               });
               flowActiveOnProject = true;
             }
@@ -206,9 +208,12 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     if (flowShouldRun) {
       flowShouldRun = false;
       (flowInitialized ?
-        Promise.resolve() :
+        (flowInitError ? Promise.reject(flowInitError) : Promise.resolve()) :
         flowInitializationPromise)
-      .then(() => flowCheck(compiler.options.context))
+      .then(
+        () => flowCheck(compiler.options.context),
+        e => Promise.reject(e) // don't run a check if init errored, just carry the error
+      )
       .then(() => {
         flowErrorOutput = null;
       }, error => {
diff --git a/packages/react-scripts/scripts/start.js b/packages/react-scripts/scripts/start.js
index 0e11ef0321f..c4f03dd8b06 100644
--- a/packages/react-scripts/scripts/start.js
+++ b/packages/react-scripts/scripts/start.js
@@ -60,6 +60,11 @@ if (isSmokeTest) {
   };
 }
 
+// Used to detect flow errors we want to swallow
+function isFlowIntegrationErrorMessage(message) {
+  return /^flow integration was disabled/i.test(message);
+}
+
 function setupCompiler(host, port, protocol) {
   // "Compiler" is a low-level interface to Webpack.
   // It lets us listen to some events and provide our own custom messages.
@@ -85,15 +90,25 @@ function setupCompiler(host, port, protocol) {
       clearConsole();
     }
 
+    // We need to know if there was an error preventing flow from starting so
+    // we can swallow it and show it in a more discreet manner
+    var statsMessages = stats.toJson({}, true);
+    var flowDisabledMessage = statsMessages.warnings.find(isFlowIntegrationErrorMessage);
+    statsMessages.warnings = statsMessages.warnings.filter(m => !isFlowIntegrationErrorMessage(m));
+
     // We have switched off the default Webpack output in WebpackDevServer
     // options so we are going to "massage" the warnings and errors and present
     // them in a readable focused way.
-    var messages = formatWebpackMessages(stats.toJson({}, true));
+    var messages = formatWebpackMessages(statsMessages);
     var isSuccessful = !messages.errors.length && !messages.warnings.length;
     var showInstructions = isSuccessful && (isInteractive || isFirstCompile);
 
     if (isSuccessful) {
       console.log(chalk.green('Compiled successfully!'));
+      // If flow was disabled, report it
+      if (flowDisabledMessage) {
+        console.log(chalk.yellow('Flow checks were skipped.'));
+      }
     }
 
     if (showInstructions) {
@@ -133,6 +148,11 @@ function setupCompiler(host, port, protocol) {
       console.log('Use ' + chalk.yellow('/* eslint-disable */') + ' to ignore all warnings in a file.');
       console.log('Use ' + chalk.yellow('// $FlowFixMe') + ' to ignore flow-related warnings on the next line.');
     }
+
+    // We print why flow was disabled
+    if (flowDisabledMessage) {
+      console.log(flowDisabledMessage);
+    }
   });
 }
 

From cabeadb25e7c5fd575f44addab9e1458ed40d0d8 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 19:40:18 +0100
Subject: [PATCH 30/74] Don't fail on tarball react-scripts

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 411a6e225b0..341effaf816 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -133,6 +133,9 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
       ['install', '--overwrite', '--flowVersion=' + localVersion],
       { cwd: projectPath }
     )
+    // This operation will fail if react-scripts is a path to a tarball in the
+    // package.json (like in End To End testing!). So we swallow this error.
+    .catch((e) => /invalid comparator/i.test(e.message) ? true : Promise.reject(e)) 
   ].concat(
     Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
       flowTypedPath,

From fa6d3c8de66f5a338dad97ec1c9cab217e10e1b0 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 19:44:50 +0100
Subject: [PATCH 31/74] Celebrate when the flow tests pass!

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 3 +++
 packages/react-scripts/scripts/start.js         | 4 +++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 341effaf816..f077f6052c5 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -219,6 +219,7 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
       )
       .then(() => {
         flowErrorOutput = null;
+        compilation.flowPassed = true;
       }, error => {
         flowErrorOutput = stripFlowLoadingIndicators(error.message);
         compilation.warnings.push(flowErrorOutput);
@@ -228,6 +229,8 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
       // Output a warning if flow failed in a previous run
       if (flowErrorOutput) {
         compilation.warnings.push(flowErrorOutput);
+      } else {
+        compilation.flowPassed = true;
       }
       callback();
     }
diff --git a/packages/react-scripts/scripts/start.js b/packages/react-scripts/scripts/start.js
index c4f03dd8b06..abd4cc34398 100644
--- a/packages/react-scripts/scripts/start.js
+++ b/packages/react-scripts/scripts/start.js
@@ -105,10 +105,12 @@ function setupCompiler(host, port, protocol) {
 
     if (isSuccessful) {
       console.log(chalk.green('Compiled successfully!'));
-      // If flow was disabled, report it
       if (flowDisabledMessage) {
         console.log(chalk.yellow('Flow checks were skipped.'));
       }
+      if (stats.compilation.flowPassed) {
+        console.log(chalk.green('Flow checks have passed.'));
+      }
     }
 
     if (showInstructions) {

From 05ae46061b29bf9f29ec7feb9dab8b8d7fc479c8 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 20:01:28 +0100
Subject: [PATCH 32/74] Show npm commands in cyan

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index f077f6052c5..a95b0c232c9 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -1,5 +1,6 @@
 var fs = require('fs');
 var path = require('path');
+var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
 const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
@@ -117,7 +118,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
         Promise.reject(new Error(
           'Flow integration was disabled because the global Flow version does not match.\n' +
           'You may either remove the global Flow installation or install a compatible version:\n' +
-          '  npm install -g flow-bin@' + localVersion
+          chalk.cyan('  npm install -g flow-bin@' + localVersion)
         )) :
         localVersion
     )

From e30a95920351ef5b7c82e2ee571b31088b0dd522 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 20:09:02 +0100
Subject: [PATCH 33/74] "Hide" flow err suppression in dev utils

---
 .../react-dev-utils/formatWebpackMessages.js  | 18 +++++++++++++++---
 packages/react-scripts/scripts/start.js       | 19 ++++---------------
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/packages/react-dev-utils/formatWebpackMessages.js b/packages/react-dev-utils/formatWebpackMessages.js
index 88834a9fc62..07bced666f3 100644
--- a/packages/react-dev-utils/formatWebpackMessages.js
+++ b/packages/react-dev-utils/formatWebpackMessages.js
@@ -20,6 +20,11 @@ function isLikelyASyntaxError(message) {
   return message.indexOf(friendlySyntaxErrorLabel) !== -1;
 }
 
+// Used to detect flow errors we want to swallow
+function isFlowIntegrationErrorMessage(message) {
+  return /^flow integration was disabled/i.test(message);
+}
+
 // Cleans up webpack error messages.
 function formatMessage(message) {
   var lines = message.split('\n');
@@ -113,15 +118,22 @@ function formatMessage(message) {
 }
 
 function formatWebpackMessages(json) {
-  var formattedErrors = json.errors.map(function(message) {
+  var formattedErrors = json.errors
+  .filter(m => !isFlowIntegrationErrorMessage(m))
+  .map(function(message) {
     return 'Error in ' + formatMessage(message)
   });
-  var formattedWarnings = json.warnings.map(function(message) {
+  var formattedWarnings = json.warnings
+  .filter(m => !isFlowIntegrationErrorMessage(m))
+  .map(function(message) {
     return 'Warning in ' + formatMessage(message)
   });
+  var flowIntegrationError = [].concat(json.errors, json.warnings)
+  .find(isFlowIntegrationErrorMessage);
   var result = {
     errors: formattedErrors,
-    warnings: formattedWarnings
+    warnings: formattedWarnings,
+    flowIntegrationError: flowIntegrationError
   };
   if (result.errors.some(isLikelyASyntaxError)) {
     // If there are any syntax errors, show just them.
diff --git a/packages/react-scripts/scripts/start.js b/packages/react-scripts/scripts/start.js
index abd4cc34398..0d53ce80495 100644
--- a/packages/react-scripts/scripts/start.js
+++ b/packages/react-scripts/scripts/start.js
@@ -60,11 +60,6 @@ if (isSmokeTest) {
   };
 }
 
-// Used to detect flow errors we want to swallow
-function isFlowIntegrationErrorMessage(message) {
-  return /^flow integration was disabled/i.test(message);
-}
-
 function setupCompiler(host, port, protocol) {
   // "Compiler" is a low-level interface to Webpack.
   // It lets us listen to some events and provide our own custom messages.
@@ -90,22 +85,16 @@ function setupCompiler(host, port, protocol) {
       clearConsole();
     }
 
-    // We need to know if there was an error preventing flow from starting so
-    // we can swallow it and show it in a more discreet manner
-    var statsMessages = stats.toJson({}, true);
-    var flowDisabledMessage = statsMessages.warnings.find(isFlowIntegrationErrorMessage);
-    statsMessages.warnings = statsMessages.warnings.filter(m => !isFlowIntegrationErrorMessage(m));
-
     // We have switched off the default Webpack output in WebpackDevServer
     // options so we are going to "massage" the warnings and errors and present
     // them in a readable focused way.
-    var messages = formatWebpackMessages(statsMessages);
+    var messages = formatWebpackMessages(stats.toJson({}, true));
     var isSuccessful = !messages.errors.length && !messages.warnings.length;
     var showInstructions = isSuccessful && (isInteractive || isFirstCompile);
 
     if (isSuccessful) {
       console.log(chalk.green('Compiled successfully!'));
-      if (flowDisabledMessage) {
+      if (messages.isFlowIntegrationErrorMessage) {
         console.log(chalk.yellow('Flow checks were skipped.'));
       }
       if (stats.compilation.flowPassed) {
@@ -152,8 +141,8 @@ function setupCompiler(host, port, protocol) {
     }
 
     // We print why flow was disabled
-    if (flowDisabledMessage) {
-      console.log(flowDisabledMessage);
+    if (messages.isFlowIntegrationErrorMessage) {
+      console.log(messages.isFlowIntegrationErrorMessage);
     }
   });
 }

From 3ed5f2c5f21ba4955a90f238280eec838c9a341a Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Mon, 12 Dec 2016 20:09:42 +0100
Subject: [PATCH 34/74] Only highlight the npm word

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index a95b0c232c9..11725549da8 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -118,7 +118,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
         Promise.reject(new Error(
           'Flow integration was disabled because the global Flow version does not match.\n' +
           'You may either remove the global Flow installation or install a compatible version:\n' +
-          chalk.cyan('  npm install -g flow-bin@' + localVersion)
+          '  ' + chalk.cyan('npm') + ' install -g flow-bin@' + localVersion
         )) :
         localVersion
     )

From 026e5811b40e97821e5aaf1dc357c98e7b620e4b Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 15:41:06 +0100
Subject: [PATCH 35/74] Make flow-typed provision sequential

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 25 ++++++++++---------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 11725549da8..6e4c557f9d7 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -136,19 +136,20 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
     )
     // This operation will fail if react-scripts is a path to a tarball in the
     // package.json (like in End To End testing!). So we swallow this error.
-    .catch((e) => /invalid comparator/i.test(e.message) ? true : Promise.reject(e)) 
-  ].concat(
-    Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
-      flowTypedPath,
-      [
-        'install',
-        packageName + '@' + otherFlowTypedDefs[packageName],
-        '--overwrite',
-        '--flowVersion=' + localVersion
-      ],
-      { cwd: projectPath }
+    .catch((e) => /invalid comparator/i.test(e.message) ? true : Promise.reject(e))
+    .then(() => Promise.all(
+      Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
+        flowTypedPath,
+        [
+          'install',
+          packageName + '@' + otherFlowTypedDefs[packageName],
+          '--overwrite',
+          '--flowVersion=' + localVersion
+        ],
+        { cwd: projectPath }
+      ))
     ))
-  )));
+  ]));
 }
 
 function flowCheck(projectPath) {

From 6e4412407629739ef503ce4d1b3db37717598e59 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 15:44:29 +0100
Subject: [PATCH 36/74] Redisign & simplify flow e2e tests

---
 tasks/e2e.sh | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 3b57c93d5a8..7a31e12ec68 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -166,16 +166,14 @@ npm start -- --smoke-test
 # Test optional flow enabling
 cp src/App.js src/App.backup.js
 cp .gitignore .gitignore.backup
-echo "
-/* @flow */
-var wrong: string = 0;
-" > src/App.js
+echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
-CI=true npm run build >> errors.log 2>> errors.log || true
-cat errors.log | grep "This type is incompatible with"
+npm start -- --smoke-test
+npm run build
 test -e .flowconfig
+test -d flow-typed
 cat .gitignore | grep flow-typed
-rm src/App.js .gitignore errors.log
+rm src/App.js .gitignore
 cp src/App.backup.js src/App.js
 cp .gitignore.backup .gitignore
 rm src/App.backup.js .gitignore.backup .flowconfig
@@ -218,16 +216,15 @@ npm start -- --smoke-test
 # Test optional flow enabling
 cp src/App.js src/App.backup.js
 cp .gitignore .gitignore.backup
-echo "
-/* @flow */
-var wrong: string = 0;
-" > src/App.js
+echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
-CI=true npm run build >> errors.log 2>> errors.log || true
-cat errors.log | grep "This type is incompatible with"
+cp src/App.js /Users/rricard/app.js
+npm start -- --smoke-test
+npm run build
 test -e .flowconfig
+test -d flow-typed
 cat .gitignore | grep flow-typed
-rm src/App.js .gitignore errors.log
+rm src/App.js .gitignore
 cp src/App.backup.js src/App.js
 cp .gitignore.backup .gitignore
 rm src/App.backup.js .gitignore.backup .flowconfig

From 3047218b10e8ca8662762c3ffc2f05d5adf8a072 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 16:15:15 +0100
Subject: [PATCH 37/74] Correctly ignore invalid comp errors

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 6e4c557f9d7..4aea3f17bcf 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -136,7 +136,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
     )
     // This operation will fail if react-scripts is a path to a tarball in the
     // package.json (like in End To End testing!). So we swallow this error.
-    .catch((e) => /invalid comparator/i.test(e.message) ? true : Promise.reject(e))
+    .catch((e) => /(invalid comparator)|(unable to rebase the local cache repo)/i.test(e.message) ? true : Promise.reject(e))
     .then(() => Promise.all(
       Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
         flowTypedPath,

From 09c2c13ac0da917634fd330dae8c552fac7ffcbe Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 16:23:04 +0100
Subject: [PATCH 38/74] Add ref to an issue comment on the silencing

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 4aea3f17bcf..fecdd33d56a 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -136,6 +136,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
     )
     // This operation will fail if react-scripts is a path to a tarball in the
     // package.json (like in End To End testing!). So we swallow this error.
+    // See https://github.com/flowtype/flow-typed/issues/399#issuecomment-266766678
     .catch((e) => /(invalid comparator)|(unable to rebase the local cache repo)/i.test(e.message) ? true : Promise.reject(e))
     .then(() => Promise.all(
       Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(

From 3949fb3f771355171eea6f64a97278868d6332b4 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 17:03:53 +0100
Subject: [PATCH 39/74] Remove debugging command in e2e.sh

---
 tasks/e2e.sh | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 7a31e12ec68..7143a944446 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -218,7 +218,6 @@ cp src/App.js src/App.backup.js
 cp .gitignore .gitignore.backup
 echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
-cp src/App.js /Users/rricard/app.js
 npm start -- --smoke-test
 npm run build
 test -e .flowconfig

From 159638b98bdcfd2e138b039492526e0b9fd2f369 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 17:14:40 +0100
Subject: [PATCH 40/74] Remove planning to add the feature in doc[ci skip]

It's there now!
---
 packages/react-scripts/template/README.md | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/react-scripts/template/README.md b/packages/react-scripts/template/README.md
index 2c3a3338114..c6fb7181509 100644
--- a/packages/react-scripts/template/README.md
+++ b/packages/react-scripts/template/README.md
@@ -488,7 +488,6 @@ Flow errors will show up alongside ESLint errors as you work on your application
 >Note: If your global flow installation version differs from react-scripts's flow version, you may experience slower compilation times while going back and forth between your app and your IDE (that may use your global flow). Ensure you have the same `flow-bin` version [here](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-dev-utils/package.json).
 
 You can optionally use an IDE like [Nuclide](https://nuclide.io/docs/languages/flow/) for a better integrated experience.
-In the future we plan to integrate it into Create React App even more closely.
 
 To learn more about Flow, check out [its documentation](https://flowtype.org/).
 

From 5105c29b5000850eb0b7eb6c78daadad0f3287e1 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 17:36:07 +0100
Subject: [PATCH 41/74] No build test for flow (duplicate)

---
 tasks/e2e.sh | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 7143a944446..a0a96833283 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -169,7 +169,6 @@ cp .gitignore .gitignore.backup
 echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
 npm start -- --smoke-test
-npm run build
 test -e .flowconfig
 test -d flow-typed
 cat .gitignore | grep flow-typed
@@ -219,7 +218,6 @@ cp .gitignore .gitignore.backup
 echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
 npm start -- --smoke-test
-npm run build
 test -e .flowconfig
 test -d flow-typed
 cat .gitignore | grep flow-typed

From 4fa4569db9668eaaf5d5f6a990b6f27a556d766c Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Tue, 13 Dec 2016 18:37:50 +0100
Subject: [PATCH 42/74] Simpler second flow test

This also let it test the idempotence of the flow addition
---
 tasks/e2e.sh | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index a0a96833283..5df6fb5a68a 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -165,18 +165,15 @@ npm start -- --smoke-test
 
 # Test optional flow enabling
 cp src/App.js src/App.backup.js
-cp .gitignore .gitignore.backup
 echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
 npm start -- --smoke-test
 test -e .flowconfig
 test -d flow-typed
 cat .gitignore | grep flow-typed
-rm src/App.js .gitignore
+rm src/App.js
 cp src/App.backup.js src/App.js
-cp .gitignore.backup .gitignore
-rm src/App.backup.js .gitignore.backup .flowconfig
-rm -rf flow-typed
+rm src/App.backup.js
 
 # ******************************************************************************
 # Finally, let's check that everything still works after ejecting.
@@ -218,14 +215,8 @@ cp .gitignore .gitignore.backup
 echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
 npm start -- --smoke-test
-test -e .flowconfig
-test -d flow-typed
-cat .gitignore | grep flow-typed
-rm src/App.js .gitignore
 cp src/App.backup.js src/App.js
-cp .gitignore.backup .gitignore
-rm src/App.backup.js .gitignore.backup .flowconfig
-rm -rf flow-typed
+rm src/App.backup.js
 
 # ******************************************************************************
 # Test --scripts-version with a version number

From ba483c66571c2e58373b0237516eadd5e4ded4de Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Wed, 14 Dec 2016 12:16:02 +0100
Subject: [PATCH 43/74] After eject, the .flowconfig should stay

---
 tasks/e2e.sh | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tasks/e2e.sh b/tasks/e2e.sh
index 5df6fb5a68a..ecdde8bbe22 100755
--- a/tasks/e2e.sh
+++ b/tasks/e2e.sh
@@ -196,7 +196,6 @@ test -e build/static/js/*.js
 test -e build/static/css/*.css
 test -e build/static/media/*.svg
 test -e build/favicon.ico
-test ! -e .flowconfig
 
 # Run tests, overring the watch option to disable it.
 # `CI=true npm test` won't work here because `npm test` becomes just `jest`.

From a48e8c3ca023f11e48fdc05b6c79012ade173009 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Wed, 14 Dec 2016 12:50:17 +0100
Subject: [PATCH 44/74] Use Flow 0.37.0

---
 packages/react-dev-utils/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index 89776f48207..f075b0dac90 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -27,7 +27,7 @@
     "ansi-html": "0.0.5",
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
-    "flow-bin": "^0.36.0",
+    "flow-bin": "^0.37.0",
     "flow-typed": "^2.0.0",
     "html-entities": "1.2.0",
     "opn": "4.0.2",

From 9e1957e141efc66f13150a4182a22dc41cf27feb Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Wed, 14 Dec 2016 17:56:56 +0100
Subject: [PATCH 45/74] Directly target the flow-typed executable

Not the .bin version
---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index fecdd33d56a..9323683a01a 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -3,7 +3,7 @@ var path = require('path');
 var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
-const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
+const flowTypedPath = path.join(__dirname, 'node_modules', 'flow-typed', 'dist', 'cli.js');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;

From c8340958cd1418f4dc6a95f4f9d0484577c08f3b Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Wed, 14 Dec 2016 18:04:07 +0100
Subject: [PATCH 46/74] Revert "Directly target the flow-typed executable"

This reverts commit 9e1957e141efc66f13150a4182a22dc41cf27feb.
---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 9323683a01a..fecdd33d56a 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -3,7 +3,7 @@ var path = require('path');
 var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
-const flowTypedPath = path.join(__dirname, 'node_modules', 'flow-typed', 'dist', 'cli.js');
+const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;

From f5d39828ff32755e314c5aca72a70256313e02e0 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 15 Dec 2016 16:37:53 +0100
Subject: [PATCH 47/74] Find flow-typed in the npm flat struct

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index fecdd33d56a..ea5b3584fc1 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -3,7 +3,7 @@ var path = require('path');
 var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
-const flowTypedPath = path.join(__dirname, 'node_modules', '.bin', 'flow-typed');
+const flowTypedPath = path.join(__dirname, '..' , '..', 'node_modules', '.bin', 'flow-typed');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;

From cfc1115e4a9a544ee5998702b4ef8ce78c45d68d Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 15 Dec 2016 16:49:43 +0100
Subject: [PATCH 48/74] Define flow-typed path with project root

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index ea5b3584fc1..93b6fde05e2 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -3,7 +3,6 @@ var path = require('path');
 var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
-const flowTypedPath = path.join(__dirname, '..' , '..', 'node_modules', '.bin', 'flow-typed');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;
@@ -109,6 +108,7 @@ function getFlowVersion(options) {
 }
 
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
+  const flowTypedPath = path.join(projectPath, 'node_modules', '.bin', 'flow-typed');
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   const gitignorePath = path.join(projectPath, '.gitignore');
   return getFlowVersion().then(localVersion => 

From 030f7c173f42543b476c2e7c75a451e4728fcd01 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 15 Dec 2016 17:15:42 +0100
Subject: [PATCH 49/74] Resolve flow-typed via module resolution

And boot it like the CLI boots in flow-typed sources
---
 .../react-dev-utils/FlowTypecheckPlugin.js    |  2 +-
 packages/react-dev-utils/package.json         |  1 +
 packages/react-dev-utils/runFlowTyped.js      | 26 +++++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 packages/react-dev-utils/runFlowTyped.js

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 93b6fde05e2..597e33647ea 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -3,6 +3,7 @@ var path = require('path');
 var chalk = require('chalk');
 var childProcess = require('child_process');
 var flowBinPath = require('flow-bin');
+const flowTypedPath = path.join(__dirname, 'runFlowTyped.js');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;
@@ -108,7 +109,6 @@ function getFlowVersion(options) {
 }
 
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
-  const flowTypedPath = path.join(projectPath, 'node_modules', '.bin', 'flow-typed');
   const flowconfigPath = path.join(projectPath, '.flowconfig');
   const gitignorePath = path.join(projectPath, '.gitignore');
   return getFlowVersion().then(localVersion => 
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index f075b0dac90..5ed882dd27b 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -13,6 +13,7 @@
   "files": [
     "clearConsole.js",
     "FlowTypecheckPlugin.js",
+    "runFlowTyped.js",
     "checkRequiredFiles.js",
     "formatWebpackMessages.js",
     "getProcessForPort.js",
diff --git a/packages/react-dev-utils/runFlowTyped.js b/packages/react-dev-utils/runFlowTyped.js
new file mode 100644
index 00000000000..39364cc31c3
--- /dev/null
+++ b/packages/react-dev-utils/runFlowTyped.js
@@ -0,0 +1,26 @@
+#!/usr/bin/env node
+var flowTyped = require('flow-typed');
+var fs = require('fs');
+var path = require('path');
+
+// Extracted from flow-typed repository: https://github.com/flowtype/flow-typed/blob/master/cli/src/cli.js#L67
+/**
+ * Look to see if the CWD is within an npm project. If it is, and that project
+ * has a flow-typed CLI `npm install`ed, use that version instead of the global
+ * version of the CLI.
+ */
+const CWD = process.cwd();
+let currDir = CWD;
+let lastDir = null;
+while (currDir !== lastDir) {
+  const localCLIPath = path.join(currDir, 'node_modules', '.bin', 'flow-typed');
+  try {
+    if (fs.statSync(localCLIPath).isFile()) {
+      flowTyped.runCLI = require.call(null, localCLIPath).runCLI;
+      break;
+    }
+  } catch (e) { /* File doesn't exist, move up a dir... */ }
+  lastDir = currDir;
+  currDir = path.resolve(currDir, '..');
+}
+flowTyped.runCLI();

From 37444f2aec66bbc3279ed05618742b56a0924015 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 15 Dec 2016 17:19:46 +0100
Subject: [PATCH 50/74] Remove unneeded complexity

---
 packages/react-dev-utils/runFlowTyped.js | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/packages/react-dev-utils/runFlowTyped.js b/packages/react-dev-utils/runFlowTyped.js
index 39364cc31c3..07f93e6d119 100644
--- a/packages/react-dev-utils/runFlowTyped.js
+++ b/packages/react-dev-utils/runFlowTyped.js
@@ -1,26 +1,4 @@
 #!/usr/bin/env node
 var flowTyped = require('flow-typed');
-var fs = require('fs');
-var path = require('path');
 
-// Extracted from flow-typed repository: https://github.com/flowtype/flow-typed/blob/master/cli/src/cli.js#L67
-/**
- * Look to see if the CWD is within an npm project. If it is, and that project
- * has a flow-typed CLI `npm install`ed, use that version instead of the global
- * version of the CLI.
- */
-const CWD = process.cwd();
-let currDir = CWD;
-let lastDir = null;
-while (currDir !== lastDir) {
-  const localCLIPath = path.join(currDir, 'node_modules', '.bin', 'flow-typed');
-  try {
-    if (fs.statSync(localCLIPath).isFile()) {
-      flowTyped.runCLI = require.call(null, localCLIPath).runCLI;
-      break;
-    }
-  } catch (e) { /* File doesn't exist, move up a dir... */ }
-  lastDir = currDir;
-  currDir = path.resolve(currDir, '..');
-}
 flowTyped.runCLI();

From 08ca7837c946c77278403c218a8f723dcf75a799 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Thu, 15 Dec 2016 17:27:31 +0100
Subject: [PATCH 51/74] Make run flow-typed executable

---
 packages/react-dev-utils/runFlowTyped.js | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 mode change 100644 => 100755 packages/react-dev-utils/runFlowTyped.js

diff --git a/packages/react-dev-utils/runFlowTyped.js b/packages/react-dev-utils/runFlowTyped.js
old mode 100644
new mode 100755

From 51cca10431be2a3cf0b2cc0c5048fb08f1d1a15d Mon Sep 17 00:00:00 2001
From: Gregor Weber <gregorwbr@gmail.com>
Date: Sat, 18 Mar 2017 21:06:31 +0100
Subject: [PATCH 52/74] Don't put flow-typed on gitignore

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 597e33647ea..9f742b6ea25 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -110,8 +110,7 @@ function getFlowVersion(options) {
 
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
-  const gitignorePath = path.join(projectPath, '.gitignore');
-  return getFlowVersion().then(localVersion => 
+  return getFlowVersion().then(localVersion =>
     getFlowVersion({global: true}).catch(() => localVersion)
     .then(globalVersion =>
       globalVersion !== localVersion ?
@@ -124,11 +123,7 @@ function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
     )
   )
   .then(localVersion => Promise.all([
-    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n'))
-    .then(wroteFlowconfig => wroteFlowconfig ?
-      writeInFileIfNotPresent(gitignorePath, 'flow-typed', 'flow-typed/npm') :
-      false
-    ),
+    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
     execOneTime(
       flowTypedPath,
       ['install', '--overwrite', '--flowVersion=' + localVersion],

From a3a78f77e93517a41f42ac7c001d7df93489318b Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 16:39:29 -0400
Subject: [PATCH 53/74] Appease linter

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 235 +++++++++---------
 packages/react-dev-utils/runFlowTyped.js      |  12 +
 2 files changed, 128 insertions(+), 119 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 9f742b6ea25..3fbf2059e8f 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -1,3 +1,14 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+'use strict';
+
 var fs = require('fs');
 var path = require('path');
 var chalk = require('chalk');
@@ -7,15 +18,15 @@ const flowTypedPath = path.join(__dirname, 'runFlowTyped.js');
 
 function stripFlowLoadingIndicators(message) {
   var newMessage = message;
-  var launchingIndex = newMessage.indexOf("Launching Flow server for");
+  var launchingIndex = newMessage.indexOf('Launching Flow server for');
   if (launchingIndex >= 0) {
     newMessage = newMessage.slice(0, launchingIndex);
   }
-  var stillIndex = newMessage.indexOf("flow is still initializing");
+  var stillIndex = newMessage.indexOf('flow is still initializing');
   if (stillIndex >= 0) {
     newMessage = newMessage.slice(0, stillIndex);
   }
-  var notRespIndex = newMessage.indexOf("The flow server is not responding");
+  var notRespIndex = newMessage.indexOf('The flow server is not responding');
   if (notRespIndex >= 0) {
     newMessage = newMessage.slice(0, notRespIndex);
   }
@@ -24,13 +35,9 @@ function stripFlowLoadingIndicators(message) {
 
 function execOneTime(command, args, options) {
   return new Promise((resolve, reject) => {
-    var stdout = new Buffer("");
-    var stderr = new Buffer("");
-    var oneTimeProcess = childProcess.spawn(
-      command,
-      args,
-      options
-    );
+    var stdout = new Buffer('');
+    var stderr = new Buffer('');
+    var oneTimeProcess = childProcess.spawn(command, args, options);
     oneTimeProcess.stdout.on('data', chunk => {
       stdout = Buffer.concat([stdout, chunk]);
     });
@@ -43,9 +50,7 @@ function execOneTime(command, args, options) {
         case 0:
           return resolve(stdout);
         default:
-          return reject(new Error(
-            Buffer.concat([stdout, stderr]).toString()
-          ));
+          return reject(new Error(Buffer.concat([stdout, stderr]).toString()));
       }
     });
   });
@@ -68,92 +73,77 @@ function writeFileIfDoesNotExist(path, data) {
   });
 }
 
-function writeInFileIfNotPresent(path, contentToAssert, contentToAppend) {
-  return new Promise((resolve, reject) => {
-    fs.exists(path, exists => {
-      if (!exists) {
-        fs.writeFile(path, contentToAppend, err => {
-          if (err) {
-            return reject(err);
-          }
-          resolve(true);
-        });
-      } else {
-        fs.readFile(path, (err, existingContent) => {
-          if (err) {
-            return reject(err);
-          }
-          if (existingContent.indexOf(contentToAssert) < 0) {
-            fs.appendFile(path, contentToAppend, err => {
-              if (err) {
-                return reject(err);
-              }
-              resolve(true);
-            });
-          } else {
-            resolve(false);
-          }
-        });
-      }
-    });
-  });
-}
-
 function getFlowVersion(options) {
-  return execOneTime(
-    (options || {}).global ? "flow" : flowBinPath,
-    ['version', '--json']
-  )
-  .then(rawData => JSON.parse(rawData))
-  .then(versionData => versionData.semver);
+  return execOneTime((options || {}).global ? 'flow' : flowBinPath, [
+    'version',
+    '--json',
+  ])
+    .then(rawData => JSON.parse(rawData))
+    .then(versionData => versionData.semver);
 }
 
 function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
   const flowconfigPath = path.join(projectPath, '.flowconfig');
-  return getFlowVersion().then(localVersion =>
-    getFlowVersion({global: true}).catch(() => localVersion)
-    .then(globalVersion =>
-      globalVersion !== localVersion ?
-        Promise.reject(new Error(
-          'Flow integration was disabled because the global Flow version does not match.\n' +
-          'You may either remove the global Flow installation or install a compatible version:\n' +
-          '  ' + chalk.cyan('npm') + ' install -g flow-bin@' + localVersion
-        )) :
-        localVersion
-    )
-  )
-  .then(localVersion => Promise.all([
-    writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
-    execOneTime(
-      flowTypedPath,
-      ['install', '--overwrite', '--flowVersion=' + localVersion],
-      { cwd: projectPath }
-    )
-    // This operation will fail if react-scripts is a path to a tarball in the
-    // package.json (like in End To End testing!). So we swallow this error.
-    // See https://github.com/flowtype/flow-typed/issues/399#issuecomment-266766678
-    .catch((e) => /(invalid comparator)|(unable to rebase the local cache repo)/i.test(e.message) ? true : Promise.reject(e))
-    .then(() => Promise.all(
-      Object.keys(otherFlowTypedDefs).map((packageName) => execOneTime(
+  return getFlowVersion()
+    .then(localVersion =>
+      getFlowVersion({ global: true })
+        .catch(() => localVersion)
+        .then(
+          globalVersion =>
+            globalVersion !== localVersion
+              ? Promise.reject(
+                  new Error(
+                    'Flow integration was disabled because the global Flow version does not match.\n' +
+                      'You may either remove the global Flow installation or install a compatible version:\n' +
+                      '  ' +
+                      chalk.cyan('npm') +
+                      ' install -g flow-bin@' +
+                      localVersion
+                  )
+                )
+              : localVersion
+        ))
+    .then(localVersion => Promise.all([
+      writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
+      execOneTime(
         flowTypedPath,
-        [
-          'install',
-          packageName + '@' + otherFlowTypedDefs[packageName],
-          '--overwrite',
-          '--flowVersion=' + localVersion
-        ],
+        ['install', '--overwrite', '--flowVersion=' + localVersion],
         { cwd: projectPath }
-      ))
-    ))
-  ]));
+      )
+        // This operation will fail if react-scripts is a path to a tarball in the
+        // package.json (like in End To End testing!). So we swallow this error.
+        // See https://github.com/flowtype/flow-typed/issues/399#issuecomment-266766678
+        .catch(
+          e =>
+            /(invalid comparator)|(unable to rebase the local cache repo)/i.test(
+              e.message
+            )
+              ? true
+              : Promise.reject(e)
+        )
+        .then(() =>
+          Promise.all(
+            Object.keys(
+              otherFlowTypedDefs
+            ).map(packageName =>
+              execOneTime(
+                flowTypedPath,
+                [
+                  'install',
+                  packageName + '@' + otherFlowTypedDefs[packageName],
+                  '--overwrite',
+                  '--flowVersion=' + localVersion,
+                ],
+                { cwd: projectPath }
+              ))
+          )),
+    ]));
 }
 
 function flowCheck(projectPath) {
-  return execOneTime(
-    flowBinPath,
-    ['status', '--color=always'],
-    { cwd: projectPath }
-  );
+  return execOneTime(flowBinPath, ['status', '--color=always'], {
+    cwd: projectPath,
+  });
 }
 
 function FlowTypecheckPlugin(options) {
@@ -173,34 +163,38 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
   var flowShouldRun = false;
   var flowErrorOutput = null;
 
-  // During module traversal, assert the presence of an @ flow in a module
-  compiler.plugin('compilation', (compilation, params) => {
+  // During module traversal, assert the presence of an @flow in a module
+  compiler.plugin('compilation', compilation => {
     compilation.plugin('normal-module-loader', (loaderContext, module) => {
       // We're only checking the presence of flow in non-node_modules
       // (some dependencies may keep their flow comments, we don't want to match them)
-      if (module.resource.indexOf("node_modules") < 0) {
+      if (module.resource.indexOf('node_modules') < 0) {
         // We use webpack's cached FileSystem to avoid slowing down compilation
         loaderContext.fs.readFile(module.resource, (err, data) => {
           if (data && data.toString().indexOf('@flow') >= 0) {
             if (!flowActiveOnProject) {
-              flowInitializationPromise = (!compiler.parentCompilation ?
-                initializeFlow(
-                  compiler.options.context, this.flowconfig, this.otherFlowTypedDefs
-                ) : Promise.resolve()
-              )
-              .then(() => {
-                flowInitialized = true;
-              }, e => {
-                flowInitError = e;
-                return Promise.reject(e);
-              });
+              flowInitializationPromise = (!compiler.parentCompilation
+                ? initializeFlow(
+                    compiler.options.context,
+                    this.flowconfig,
+                    this.otherFlowTypedDefs
+                  )
+                : Promise.resolve()).then(
+                () => {
+                  flowInitialized = true;
+                },
+                e => {
+                  flowInitError = e;
+                  return Promise.reject(e);
+                }
+              );
               flowActiveOnProject = true;
             }
             flowShouldRun = true;
           }
         });
       }
-    })
+    });
   });
 
   // While emitting, run a flow check if flow has been detected
@@ -208,21 +202,24 @@ FlowTypecheckPlugin.prototype.apply = function(compiler) {
     // Only if a file with @ flow has been changed
     if (flowShouldRun) {
       flowShouldRun = false;
-      (flowInitialized ?
-        (flowInitError ? Promise.reject(flowInitError) : Promise.resolve()) :
-        flowInitializationPromise)
-      .then(
-        () => flowCheck(compiler.options.context),
-        e => Promise.reject(e) // don't run a check if init errored, just carry the error
-      )
-      .then(() => {
-        flowErrorOutput = null;
-        compilation.flowPassed = true;
-      }, error => {
-        flowErrorOutput = stripFlowLoadingIndicators(error.message);
-        compilation.warnings.push(flowErrorOutput);
-      })
-      .then(callback);
+      (flowInitialized
+        ? flowInitError ? Promise.reject(flowInitError) : Promise.resolve()
+        : flowInitializationPromise)
+        .then(
+          () => flowCheck(compiler.options.context),
+          e => Promise.reject(e) // don't run a check if init errored, just carry the error
+        )
+        .then(
+          () => {
+            flowErrorOutput = null;
+            compilation.flowPassed = true;
+          },
+          error => {
+            flowErrorOutput = stripFlowLoadingIndicators(error.message);
+            compilation.warnings.push(flowErrorOutput);
+          }
+        )
+        .then(callback);
     } else {
       // Output a warning if flow failed in a previous run
       if (flowErrorOutput) {
diff --git a/packages/react-dev-utils/runFlowTyped.js b/packages/react-dev-utils/runFlowTyped.js
index 07f93e6d119..51dc717e625 100755
--- a/packages/react-dev-utils/runFlowTyped.js
+++ b/packages/react-dev-utils/runFlowTyped.js
@@ -1,4 +1,16 @@
 #!/usr/bin/env node
+
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+'use strict';
+
 var flowTyped = require('flow-typed');
 
 flowTyped.runCLI();

From eb9e341dc8fa79e4b632fad4d842ccca236eafb3 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 16:50:54 -0400
Subject: [PATCH 54/74] Update flow

---
 packages/react-dev-utils/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index 6a8f1c0676c..fe988a3029e 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -33,7 +33,7 @@
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
     "filesize": "3.3.0",
-    "flow-bin": "^0.37.0",
+    "flow-bin": "^0.44.2",
     "flow-typed": "^2.0.0",
     "gzip-size": "3.0.0",
     "html-entities": "1.2.0",

From 137f59f2332f955bbff4a3af562f2cf8bcb3283f Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 18:32:05 -0400
Subject: [PATCH 55/74] Add basic flow type checking

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 286 ++++++------------
 1 file changed, 93 insertions(+), 193 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 3fbf2059e8f..c035ad5c929 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -9,31 +9,13 @@
 
 'use strict';
 
-var fs = require('fs');
-var path = require('path');
-var chalk = require('chalk');
-var childProcess = require('child_process');
-var flowBinPath = require('flow-bin');
-const flowTypedPath = path.join(__dirname, 'runFlowTyped.js');
+const fs = require('fs');
+const path = require('path');
+const chalk = require('chalk');
+const childProcess = require('child_process');
+const flowBinPath = require('flow-bin');
 
-function stripFlowLoadingIndicators(message) {
-  var newMessage = message;
-  var launchingIndex = newMessage.indexOf('Launching Flow server for');
-  if (launchingIndex >= 0) {
-    newMessage = newMessage.slice(0, launchingIndex);
-  }
-  var stillIndex = newMessage.indexOf('flow is still initializing');
-  if (stillIndex >= 0) {
-    newMessage = newMessage.slice(0, stillIndex);
-  }
-  var notRespIndex = newMessage.indexOf('The flow server is not responding');
-  if (notRespIndex >= 0) {
-    newMessage = newMessage.slice(0, notRespIndex);
-  }
-  return newMessage;
-}
-
-function execOneTime(command, args, options) {
+function exec(command, args, options) {
   return new Promise((resolve, reject) => {
     var stdout = new Buffer('');
     var stderr = new Buffer('');
@@ -47,189 +29,107 @@ function execOneTime(command, args, options) {
     oneTimeProcess.on('error', error => reject(error));
     oneTimeProcess.on('exit', code => {
       switch (code) {
-        case 0:
+        case 0: {
           return resolve(stdout);
-        default:
+        }
+        default: {
           return reject(new Error(Buffer.concat([stdout, stderr]).toString()));
+        }
       }
     });
   });
 }
 
-function writeFileIfDoesNotExist(path, data) {
-  return new Promise((resolve, reject) => {
-    fs.exists(path, exists => {
-      if (!exists) {
-        fs.writeFile(path, data, err => {
-          if (err) {
-            return reject(err);
-          }
-          resolve(true);
-        });
-      } else {
-        resolve(false);
-      }
-    });
-  });
-}
-
-function getFlowVersion(options) {
-  return execOneTime((options || {}).global ? 'flow' : flowBinPath, [
-    'version',
-    '--json',
-  ])
-    .then(rawData => JSON.parse(rawData))
-    .then(versionData => versionData.semver);
+function filterFlowErrors(error) {
+  return error
+    .toString()
+    .split('\n')
+    .filter(line => {
+      return !(/flow is still initializing/.test(line) ||
+        /Found \d+ error/.test(line) ||
+        line.trim().length === 0);
+    })
+    .join('\n');
 }
 
-function initializeFlow(projectPath, flowconfig, otherFlowTypedDefs) {
-  const flowconfigPath = path.join(projectPath, '.flowconfig');
-  return getFlowVersion()
-    .then(localVersion =>
-      getFlowVersion({ global: true })
-        .catch(() => localVersion)
-        .then(
-          globalVersion =>
-            globalVersion !== localVersion
-              ? Promise.reject(
-                  new Error(
-                    'Flow integration was disabled because the global Flow version does not match.\n' +
-                      'You may either remove the global Flow installation or install a compatible version:\n' +
-                      '  ' +
-                      chalk.cyan('npm') +
-                      ' install -g flow-bin@' +
-                      localVersion
-                  )
-                )
-              : localVersion
-        ))
-    .then(localVersion => Promise.all([
-      writeFileIfDoesNotExist(flowconfigPath, flowconfig.join('\n')),
-      execOneTime(
-        flowTypedPath,
-        ['install', '--overwrite', '--flowVersion=' + localVersion],
-        { cwd: projectPath }
-      )
-        // This operation will fail if react-scripts is a path to a tarball in the
-        // package.json (like in End To End testing!). So we swallow this error.
-        // See https://github.com/flowtype/flow-typed/issues/399#issuecomment-266766678
-        .catch(
-          e =>
-            /(invalid comparator)|(unable to rebase the local cache repo)/i.test(
-              e.message
-            )
-              ? true
-              : Promise.reject(e)
-        )
-        .then(() =>
-          Promise.all(
-            Object.keys(
-              otherFlowTypedDefs
-            ).map(packageName =>
-              execOneTime(
-                flowTypedPath,
-                [
-                  'install',
-                  packageName + '@' + otherFlowTypedDefs[packageName],
-                  '--overwrite',
-                  '--flowVersion=' + localVersion,
-                ],
-                { cwd: projectPath }
-              ))
-          )),
-    ]));
-}
-
-function flowCheck(projectPath) {
-  return execOneTime(flowBinPath, ['status', '--color=always'], {
-    cwd: projectPath,
-  });
-}
+class FlowTypecheckPlugin {
+  constructor(options) {
+    this.shouldRun = false;
+    this.flowStarted = false;
+  }
 
-function FlowTypecheckPlugin(options) {
-  options = options || {};
-  // Contents of the generated .flowconfig if it doesn't exist
-  this.flowconfig = options.flowconfig || [];
-  // Load up other flow-typed defs outside of the package.json (implicit packages behind react-scripts)
-  // Key is the package name, value is the version number
-  this.otherFlowTypedDefs = options.otherFlowTypedDefs || {};
-}
+  startFlow(cwd) {
+    if (this.flowStarted) {
+      return Promise.resolve();
+    }
+    const flowConfigPath = path.join(cwd, '.flowconfig');
+    return new Promise((resolve, reject) => {
+      fs.stat(flowConfigPath, (err, stats) => {
+        if (err) {
+          resolve(exec(flowBinPath, ['init'], { cwd }));
+        } else {
+          resolve();
+        }
+      });
+    })
+      .then(() =>
+        exec(flowBinPath, ['stop'], { cwd }).then(() =>
+          exec(flowBinPath, ['start'], { cwd })))
+      .then(() => {
+        this.flowStarted = true;
+      });
+  }
 
-FlowTypecheckPlugin.prototype.apply = function(compiler) {
-  var flowActiveOnProject = false;
-  var flowInitialized = false;
-  var flowInitError = null;
-  var flowInitializationPromise;
-  var flowShouldRun = false;
-  var flowErrorOutput = null;
+  apply(compiler) {
+    compiler.plugin('compile', () => {
+      this.shouldRun = false;
+    });
 
-  // During module traversal, assert the presence of an @flow in a module
-  compiler.plugin('compilation', compilation => {
-    compilation.plugin('normal-module-loader', (loaderContext, module) => {
-      // We're only checking the presence of flow in non-node_modules
-      // (some dependencies may keep their flow comments, we don't want to match them)
-      if (module.resource.indexOf('node_modules') < 0) {
-        // We use webpack's cached FileSystem to avoid slowing down compilation
-        loaderContext.fs.readFile(module.resource, (err, data) => {
-          if (data && data.toString().indexOf('@flow') >= 0) {
-            if (!flowActiveOnProject) {
-              flowInitializationPromise = (!compiler.parentCompilation
-                ? initializeFlow(
-                    compiler.options.context,
-                    this.flowconfig,
-                    this.otherFlowTypedDefs
-                  )
-                : Promise.resolve()).then(
-                () => {
-                  flowInitialized = true;
-                },
-                e => {
-                  flowInitError = e;
-                  return Promise.reject(e);
-                }
-              );
-              flowActiveOnProject = true;
-            }
-            flowShouldRun = true;
-          }
-        });
-      }
+    compiler.plugin('compilation', compilation => {
+      compilation.plugin('normal-module-loader', (loaderContext, module) => {
+        if (
+          this.shouldRun ||
+          module.resource.indexOf('node_modules') !== -1 ||
+          !/[.]js(x)?$/.test(module.resource)
+        ) {
+          return;
+        }
+        if (
+          loaderContext.fs
+            .readFileSync(module.resource, 'utf8')
+            .indexOf('@flow') !== -1
+        ) {
+          this.shouldRun = true;
+        }
+      });
     });
-  });
 
-  // While emitting, run a flow check if flow has been detected
-  compiler.plugin('emit', (compilation, callback) => {
-    // Only if a file with @ flow has been changed
-    if (flowShouldRun) {
-      flowShouldRun = false;
-      (flowInitialized
-        ? flowInitError ? Promise.reject(flowInitError) : Promise.resolve()
-        : flowInitializationPromise)
-        .then(
-          () => flowCheck(compiler.options.context),
-          e => Promise.reject(e) // don't run a check if init errored, just carry the error
-        )
-        .then(
-          () => {
-            flowErrorOutput = null;
-            compilation.flowPassed = true;
-          },
-          error => {
-            flowErrorOutput = stripFlowLoadingIndicators(error.message);
-            compilation.warnings.push(flowErrorOutput);
-          }
-        )
-        .then(callback);
-    } else {
-      // Output a warning if flow failed in a previous run
-      if (flowErrorOutput) {
-        compilation.warnings.push(flowErrorOutput);
-      } else {
-        compilation.flowPassed = true;
+    // Run lint checks
+    compiler.plugin('emit', (compilation, callback) => {
+      if (!this.shouldRun) {
+        //TODO: flow did not run
+        callback();
+        return;
       }
-      callback();
-    }
-  });
-};
+      const cwd = compiler.options.context;
+      this.startFlow(cwd)
+        .then(() => {
+          exec(flowBinPath, ['status', '--color=always'], { cwd })
+            .then(() => {
+              callback();
+              //TODO: flow ran, and there was no errors
+            })
+            .catch(e => {
+              compilation.warnings.push(filterFlowErrors(e));
+              callback();
+            });
+        })
+        .catch(e => {
+          //TODO: flow failed, set a warning
+          callback();
+        });
+    });
+  }
+}
 
 module.exports = FlowTypecheckPlugin;

From 2fd2dbcb4716f3a69023294fbac078f66759e666 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 18:58:31 -0400
Subject: [PATCH 56/74] Adjust format function

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index c035ad5c929..280886ba4c9 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -40,15 +40,15 @@ function exec(command, args, options) {
   });
 }
 
-function filterFlowErrors(error) {
+function formatFlowErrors(error) {
   return error
     .toString()
     .split('\n')
     .filter(line => {
       return !(/flow is still initializing/.test(line) ||
-        /Found \d+ error/.test(line) ||
-        line.trim().length === 0);
+        /Found \d+ error/.test(line));
     })
+    .map(line => line.replace(/^Error:\s*/, ''))
     .join('\n');
 }
 
@@ -94,10 +94,9 @@ class FlowTypecheckPlugin {
         ) {
           return;
         }
+        const contents = loaderContext.fs.readFileSync(module.resource, 'utf8');
         if (
-          loaderContext.fs
-            .readFileSync(module.resource, 'utf8')
-            .indexOf('@flow') !== -1
+          /^\s*\/\/.*@flow/.test(contents) || /^\s*\/\*.*@flow/.test(contents)
         ) {
           this.shouldRun = true;
         }
@@ -120,7 +119,7 @@ class FlowTypecheckPlugin {
               //TODO: flow ran, and there was no errors
             })
             .catch(e => {
-              compilation.warnings.push(filterFlowErrors(e));
+              compilation.warnings.push(formatFlowErrors(e));
               callback();
             });
         })

From 7c5749d4b63a888e599529654a0b6a4225fa715f Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 19:59:15 -0400
Subject: [PATCH 57/74] Remove flow-typed stub

---
 packages/react-dev-utils/FlowTypecheckPlugin.js  |  1 -
 packages/react-dev-utils/package.json            |  1 -
 packages/react-dev-utils/runFlowTyped.js         | 16 ----------------
 .../react-scripts/config/webpack.config.dev.js   |  8 ++------
 .../react-scripts/config/webpack.config.prod.js  |  8 ++------
 5 files changed, 4 insertions(+), 30 deletions(-)
 delete mode 100755 packages/react-dev-utils/runFlowTyped.js

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 280886ba4c9..b77265560e1 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -106,7 +106,6 @@ class FlowTypecheckPlugin {
     // Run lint checks
     compiler.plugin('emit', (compilation, callback) => {
       if (!this.shouldRun) {
-        //TODO: flow did not run
         callback();
         return;
       }
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index fe988a3029e..b810e80b3b6 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -23,7 +23,6 @@
     "openBrowser.js",
     "openChrome.applescript",
     "prompt.js",
-    "runFlowTyped.js",
     "WatchMissingNodeModulesPlugin.js",
     "webpackHotDevClient.js"
   ],
diff --git a/packages/react-dev-utils/runFlowTyped.js b/packages/react-dev-utils/runFlowTyped.js
deleted file mode 100755
index 51dc717e625..00000000000
--- a/packages/react-dev-utils/runFlowTyped.js
+++ /dev/null
@@ -1,16 +0,0 @@
-#!/usr/bin/env node
-
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- */
-
-'use strict';
-
-var flowTyped = require('flow-typed');
-
-flowTyped.runCLI();
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 7f6bbbf20f7..1840751d8ce 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -242,12 +242,8 @@ module.exports = {
     // makes the discovery automatic so you don't have to restart.
     // See https://github.com/facebookincubator/create-react-app/issues/186
     new WatchMissingNodeModulesPlugin(paths.appNodeModules),
-    // Trigger some typechecking if a file matches with an @ flow comment
-    new FlowTypecheckPlugin({
-      otherFlowTypedDefs: {
-        jest: '18.0.0',
-      },
-    }),
+    // Run Flow on files with the @flow header
+    new FlowTypecheckPlugin(),
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index f4cf92466ab..89af42f3bde 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -278,12 +278,8 @@ module.exports = {
     new ManifestPlugin({
       fileName: 'asset-manifest.json',
     }),
-    // Run Flow only if we see some @ flow annotations, will error on CI
-    new FlowTypecheckPlugin({
-      otherFlowTypedDefs: {
-        jest: '18.0.0',
-      },
-    }),
+    // Run Flow on files with the @flow header
+    new FlowTypecheckPlugin(),
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.

From f4299ef824ce2e251b21ef8d348af802ad2b42ed Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:01:21 -0400
Subject: [PATCH 58/74] Use access instead of stat to prevent dual-compile

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index b77265560e1..b0f409c8d78 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -64,7 +64,7 @@ class FlowTypecheckPlugin {
     }
     const flowConfigPath = path.join(cwd, '.flowconfig');
     return new Promise((resolve, reject) => {
-      fs.stat(flowConfigPath, (err, stats) => {
+      fs.access(flowConfigPath, fs.constants.R_OK | fs.constants.W_OK, err => {
         if (err) {
           resolve(exec(flowBinPath, ['init'], { cwd }));
         } else {

From a3fb2dff58075a83d62b7e1a7a036b55e9163aea Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:07:03 -0400
Subject: [PATCH 59/74] Add some friendly comments

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index b0f409c8d78..3547db35bbe 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -62,6 +62,7 @@ class FlowTypecheckPlugin {
     if (this.flowStarted) {
       return Promise.resolve();
     }
+    console.log(chalk.cyan('Starting the flow server ...'));
     const flowConfigPath = path.join(cwd, '.flowconfig');
     return new Promise((resolve, reject) => {
       fs.access(flowConfigPath, fs.constants.R_OK | fs.constants.W_OK, err => {
@@ -77,6 +78,11 @@ class FlowTypecheckPlugin {
           exec(flowBinPath, ['start'], { cwd })))
       .then(() => {
         this.flowStarted = true;
+        console.log(
+          chalk.yellow(
+            'Flow is initializing, ' + chalk.bold('this might take a while ...')
+          )
+        );
       });
   }
 

From de99610715e66ad3f19d879b6d8948d95a9ba032 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:26:58 -0400
Subject: [PATCH 60/74] Lock down flow version

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 20 +++++++++++++------
 packages/react-dev-utils/package.json         |  3 +--
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 3547db35bbe..b0e9fb7a415 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -78,11 +78,6 @@ class FlowTypecheckPlugin {
           exec(flowBinPath, ['start'], { cwd })))
       .then(() => {
         this.flowStarted = true;
-        console.log(
-          chalk.yellow(
-            'Flow is initializing, ' + chalk.bold('this might take a while ...')
-          )
-        );
       });
   }
 
@@ -116,8 +111,19 @@ class FlowTypecheckPlugin {
         return;
       }
       const cwd = compiler.options.context;
+      const first = !this.flowStarted;
       this.startFlow(cwd)
         .then(() => {
+          if (first) {
+            console.log(
+              chalk.yellow(
+                'Flow is initializing, ' +
+                  chalk.bold('this might take a while...')
+              )
+            );
+          } else {
+            console.log('Running flow...');
+          }
           exec(flowBinPath, ['status', '--color=always'], { cwd })
             .then(() => {
               callback();
@@ -129,7 +135,9 @@ class FlowTypecheckPlugin {
             });
         })
         .catch(e => {
-          //TODO: flow failed, set a warning
+          compilation.warnings.push(
+            'Flow checking has been disabled due to an error in Flow.'
+          );
           callback();
         });
     });
diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index b810e80b3b6..b35129fbbc5 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -32,8 +32,7 @@
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
     "filesize": "3.3.0",
-    "flow-bin": "^0.44.2",
-    "flow-typed": "^2.0.0",
+    "flow-bin": "0.44.2",
     "gzip-size": "3.0.0",
     "html-entities": "1.2.0",
     "opn": "4.0.2",

From 29628efd12154f281e4de6892d0e5553a4f51e6b Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:38:54 -0400
Subject: [PATCH 61/74] Update comment logs

---
 packages/react-dev-utils/FlowTypecheckPlugin.js           | 1 -
 .../react-scripts/scripts/utils/createWebpackCompiler.js  | 8 +-------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index b0e9fb7a415..016a9b5abce 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -127,7 +127,6 @@ class FlowTypecheckPlugin {
           exec(flowBinPath, ['status', '--color=always'], { cwd })
             .then(() => {
               callback();
-              //TODO: flow ran, and there was no errors
             })
             .catch(e => {
               compilation.warnings.push(formatFlowErrors(e));
diff --git a/packages/react-scripts/scripts/utils/createWebpackCompiler.js b/packages/react-scripts/scripts/utils/createWebpackCompiler.js
index f2d6880d2b7..2f6f0cac2b3 100644
--- a/packages/react-scripts/scripts/utils/createWebpackCompiler.js
+++ b/packages/react-scripts/scripts/utils/createWebpackCompiler.js
@@ -74,9 +74,6 @@ module.exports = function createWebpackCompiler(config, onReadyCallback) {
 
     if (isSuccessful) {
       console.log(chalk.green('Compiled successfully!'));
-      if (messages.isFlowIntegrationErrorMessage) {
-        console.log(chalk.yellow('Flow checks were skipped.'));
-      }
     }
 
     if (typeof onReadyCallback === 'function') {
@@ -115,16 +112,13 @@ module.exports = function createWebpackCompiler(config, onReadyCallback) {
           chalk.yellow('/* eslint-disable */') +
           ' to ignore all warnings in a file.'
       );
+      // Teach some Flow tricks.
       console.log(
         'Use ' +
           chalk.yellow('// $FlowFixMe') +
           ' to ignore flow-related warnings on the next line.'
       );
     }
-
-    if (messages.isFlowIntegrationErrorMessage) {
-      console.log(messages.isFlowIntegrationErrorMessage);
-    }
   });
 
   return compiler;

From 30494dcee3f7bc80543a80bd0a52a0a6d7c59013 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:41:57 -0400
Subject: [PATCH 62/74] Remove old method

---
 .../react-dev-utils/formatWebpackMessages.js  | 25 +++++--------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/packages/react-dev-utils/formatWebpackMessages.js b/packages/react-dev-utils/formatWebpackMessages.js
index f1cee7cc04c..098c48657e2 100644
--- a/packages/react-dev-utils/formatWebpackMessages.js
+++ b/packages/react-dev-utils/formatWebpackMessages.js
@@ -22,11 +22,6 @@ function isLikelyASyntaxError(message) {
   return message.indexOf(friendlySyntaxErrorLabel) !== -1;
 }
 
-// Used to detect flow errors we want to swallow
-function isFlowIntegrationErrorMessage(message) {
-  return /^flow integration was disabled/i.test(message);
-}
-
 // Cleans up webpack error messages.
 function formatMessage(message) {
   var lines = message.split('\n');
@@ -118,23 +113,15 @@ function formatMessage(message) {
 }
 
 function formatWebpackMessages(json) {
-  var formattedErrors = json.errors
-    .filter(m => !isFlowIntegrationErrorMessage(m))
-    .map(function(message) {
-      return 'Error in ' + formatMessage(message);
-    });
-  var formattedWarnings = json.warnings
-    .filter(m => !isFlowIntegrationErrorMessage(m))
-    .map(function(message) {
-      return 'Warning in ' + formatMessage(message);
-    });
-  var flowIntegrationError = []
-    .concat(json.errors, json.warnings)
-    .find(isFlowIntegrationErrorMessage);
+  var formattedErrors = json.errors.map(function(message) {
+    return 'Error in ' + formatMessage(message);
+  });
+  var formattedWarnings = json.warnings.map(function(message) {
+    return 'Warning in ' + formatMessage(message);
+  });
   var result = {
     errors: formattedErrors,
     warnings: formattedWarnings,
-    flowIntegrationError: flowIntegrationError,
   };
   if (result.errors.some(isLikelyASyntaxError)) {
     // If there are any syntax errors, show just them.

From f850266fe07df22c8f93873bc3d556f519d75921 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 20:44:01 -0400
Subject: [PATCH 63/74] Remove from e2e

---
 tasks/e2e-simple.sh | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tasks/e2e-simple.sh b/tasks/e2e-simple.sh
index 9e9b32657f0..8859b6f3502 100755
--- a/tasks/e2e-simple.sh
+++ b/tasks/e2e-simple.sh
@@ -246,8 +246,6 @@ echo "/* @flow */" > src/App.js
 cat src/App.backup.js >> src/App.js
 npm start -- --smoke-test
 test -e .flowconfig
-test -d flow-typed
-cat .gitignore | grep flow-typed
 rm src/App.js
 cp src/App.backup.js src/App.js
 rm src/App.backup.js

From 8d1f51535eef59cbf8c37901fc448ddf21e3672a Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 21:32:56 -0400
Subject: [PATCH 64/74] Check flow version for performance

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 76 +++++++++++++++----
 1 file changed, 61 insertions(+), 15 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 016a9b5abce..1ed363d5312 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -40,22 +40,49 @@ function exec(command, args, options) {
   });
 }
 
-function formatFlowErrors(error) {
+function createVersionWarning(flowVersion) {
+  return 'Flow: ' +
+    chalk.red(
+      chalk.bold(
+        `Your global flow version is incompatible with this tool.
+To fix warning, uninstall it or run \`npm install -g flow-bin@${flowVersion}\`.`
+      )
+    );
+}
+
+function formatFlowErrors(error, flowVersion) {
   return error
     .toString()
     .split('\n')
     .filter(line => {
       return !(/flow is still initializing/.test(line) ||
-        /Found \d+ error/.test(line));
+        /Found \d+ error/.test(line) ||
+        /The flow server is not responding/.test(line) ||
+        /Going to launch a new one/.test(line) ||
+        /The flow server is not responding/.test(line) ||
+        /Spawned flow server/.test(line) ||
+        /Logs will go to/.test(line) ||
+        /version didn't match the client's/.test(line));
     })
     .map(line => line.replace(/^Error:\s*/, ''))
     .join('\n');
 }
 
+function getFlowVersion(global) {
+  return exec(global ? 'flow' : flowBinPath, ['version', '--json'])
+    .then(data => JSON.parse(data.toString('utf8')).semver || '0.0.0')
+    .catch(e => null);
+}
+
 class FlowTypecheckPlugin {
   constructor(options) {
     this.shouldRun = false;
     this.flowStarted = false;
+
+    this.flowVersion = require(path.join(
+      __dirname,
+      'package.json'
+    )).dependencies['flow-bin'];
   }
 
   startFlow(cwd) {
@@ -64,15 +91,30 @@ class FlowTypecheckPlugin {
     }
     console.log(chalk.cyan('Starting the flow server ...'));
     const flowConfigPath = path.join(cwd, '.flowconfig');
-    return new Promise((resolve, reject) => {
-      fs.access(flowConfigPath, fs.constants.R_OK | fs.constants.W_OK, err => {
-        if (err) {
-          resolve(exec(flowBinPath, ['init'], { cwd }));
-        } else {
-          resolve();
-        }
-      });
-    })
+    return getFlowVersion(true)
+      .then(globalVersion => {
+        if (globalVersion === null) return;
+        return getFlowVersion(false).then(ourVersion => {
+          if (globalVersion !== ourVersion) {
+            return Promise.reject('__FLOW_VERSION_MISMATCH__');
+          }
+        });
+      })
+      .then(
+        () => new Promise((resolve, reject) => {
+          fs.access(
+            flowConfigPath,
+            fs.constants.R_OK | fs.constants.W_OK,
+            err => {
+              if (err) {
+                resolve(exec(flowBinPath, ['init'], { cwd }));
+              } else {
+                resolve();
+              }
+            }
+          );
+        })
+      )
       .then(() =>
         exec(flowBinPath, ['stop'], { cwd }).then(() =>
           exec(flowBinPath, ['start'], { cwd })))
@@ -129,14 +171,18 @@ class FlowTypecheckPlugin {
               callback();
             })
             .catch(e => {
-              compilation.warnings.push(formatFlowErrors(e));
+              compilation.warnings.push(formatFlowErrors(e, this.flowVersion));
               callback();
             });
         })
         .catch(e => {
-          compilation.warnings.push(
-            'Flow checking has been disabled due to an error in Flow.'
-          );
+          if (e === '__FLOW_VERSION_MISMATCH__') {
+            compilation.warnings.push(createVersionWarning(this.flowVersion));
+          } else {
+            compilation.warnings.push(
+              'Flow: Type checking has been disabled due to an error in Flow.'
+            );
+          }
           callback();
         });
     });

From 1df2cb575d434c715d03008daab50f43deb06cf6 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 21:33:09 -0400
Subject: [PATCH 65/74] Remove warning prefix for flow messages

---
 packages/react-dev-utils/formatWebpackMessages.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/react-dev-utils/formatWebpackMessages.js b/packages/react-dev-utils/formatWebpackMessages.js
index 098c48657e2..509d13d90ec 100644
--- a/packages/react-dev-utils/formatWebpackMessages.js
+++ b/packages/react-dev-utils/formatWebpackMessages.js
@@ -117,6 +117,8 @@ function formatWebpackMessages(json) {
     return 'Error in ' + formatMessage(message);
   });
   var formattedWarnings = json.warnings.map(function(message) {
+    var formattedMessage = formatMessage(message);
+    if (/^Flow: /.test(message)) return formattedMessage;
     return 'Warning in ' + formatMessage(message);
   });
   var result = {

From 70ad8dd285abcc7ee43adb7afeda2555e810ec6a Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 21:33:19 -0400
Subject: [PATCH 66/74] Update README

---
 packages/react-scripts/template/README.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/react-scripts/template/README.md b/packages/react-scripts/template/README.md
index e8d57fd45e2..50a6a9b0426 100644
--- a/packages/react-scripts/template/README.md
+++ b/packages/react-scripts/template/README.md
@@ -646,13 +646,12 @@ We suggest the following approach:
 
 Here is an example of adding a [customized Bootstrap](https://medium.com/@tacomanator/customizing-create-react-app-aa9ffb88165) that follows these steps.
 
-## Adding Flow
+## Using Flow
 
 Flow is a static type checker that helps you write code with fewer bugs. Check out this [introduction to using static types in JavaScript](https://medium.com/@preethikasireddy/why-use-static-types-in-javascript-part-1-8382da1e0adb) if you are new to this concept.
 
-Flow typing is now supported out of the box. All you have to do is add the `/* @flow */` comment on top of files you
-want to typecheck. If no `.flowconfig` is present, one will be generated for you. The script will also download type
-definitions from [flow-typed](https://github.com/flowtype/flow-typed) automatically.
+Flow typing is supported out of the box. All you have to do is add the `/* @flow */` comment on top of files you
+want to typecheck. If no `.flowconfig` is present, one will be generated for you.
 
 Flow errors will show up alongside ESLint errors as you work on your application.
 
@@ -661,6 +660,7 @@ Flow errors will show up alongside ESLint errors as you work on your application
 You can optionally use an IDE like [Nuclide](https://nuclide.io/docs/languages/flow/) for a better integrated experience.
 
 To learn more about Flow, check out [its documentation](https://flowtype.org/).
+You may also want to learn how to use definitions from [flow-typed](https://github.com/flowtype/flow-typed).
 
 ## Adding Custom Environment Variables
 

From 45841cd27eb9eb680940a25c78bb5f8d65a8db90 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 21:34:11 -0400
Subject: [PATCH 67/74] Don't double compute

---
 packages/react-dev-utils/formatWebpackMessages.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/formatWebpackMessages.js b/packages/react-dev-utils/formatWebpackMessages.js
index 509d13d90ec..a2ecdbe3cc1 100644
--- a/packages/react-dev-utils/formatWebpackMessages.js
+++ b/packages/react-dev-utils/formatWebpackMessages.js
@@ -119,7 +119,7 @@ function formatWebpackMessages(json) {
   var formattedWarnings = json.warnings.map(function(message) {
     var formattedMessage = formatMessage(message);
     if (/^Flow: /.test(message)) return formattedMessage;
-    return 'Warning in ' + formatMessage(message);
+    return 'Warning in ' + formattedMessage;
   });
   var result = {
     errors: formattedErrors,

From dab6f9d73a2ce23288dc345f564a6e0289f0c49a Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 21:44:27 -0400
Subject: [PATCH 68/74] Fix linter errors

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 1ed363d5312..b9e52a546f4 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -50,7 +50,7 @@ To fix warning, uninstall it or run \`npm install -g flow-bin@${flowVersion}\`.`
     );
 }
 
-function formatFlowErrors(error, flowVersion) {
+function formatFlowErrors(error) {
   return error
     .toString()
     .split('\n')
@@ -71,11 +71,11 @@ function formatFlowErrors(error, flowVersion) {
 function getFlowVersion(global) {
   return exec(global ? 'flow' : flowBinPath, ['version', '--json'])
     .then(data => JSON.parse(data.toString('utf8')).semver || '0.0.0')
-    .catch(e => null);
+    .catch(() => null);
 }
 
 class FlowTypecheckPlugin {
-  constructor(options) {
+  constructor() {
     this.shouldRun = false;
     this.flowStarted = false;
 
@@ -101,7 +101,7 @@ class FlowTypecheckPlugin {
         });
       })
       .then(
-        () => new Promise((resolve, reject) => {
+        () => new Promise(resolve => {
           fs.access(
             flowConfigPath,
             fs.constants.R_OK | fs.constants.W_OK,
@@ -171,7 +171,7 @@ class FlowTypecheckPlugin {
               callback();
             })
             .catch(e => {
-              compilation.warnings.push(formatFlowErrors(e, this.flowVersion));
+              compilation.warnings.push(formatFlowErrors(e));
               callback();
             });
         })

From 1cb808eb4a00d49910e5b6cd0c8684162ef96b43 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Sat, 22 Apr 2017 22:08:57 -0400
Subject: [PATCH 69/74] Use default perm check

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index b9e52a546f4..7ec08238bde 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -102,17 +102,13 @@ class FlowTypecheckPlugin {
       })
       .then(
         () => new Promise(resolve => {
-          fs.access(
-            flowConfigPath,
-            fs.constants.R_OK | fs.constants.W_OK,
-            err => {
-              if (err) {
-                resolve(exec(flowBinPath, ['init'], { cwd }));
-              } else {
-                resolve();
-              }
+          fs.access(flowConfigPath, err => {
+            if (err) {
+              resolve(exec(flowBinPath, ['init'], { cwd }));
+            } else {
+              resolve();
             }
-          );
+          });
         })
       )
       .then(() =>

From e94387ca8de1b4ed68dda9ee7328c97e06c0a890 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Mon, 24 Apr 2017 16:31:30 -0400
Subject: [PATCH 70/74] Handle already running server since it exits with a
 non-zero

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 7ec08238bde..390d1b9802a 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -111,9 +111,18 @@ class FlowTypecheckPlugin {
           });
         })
       )
-      .then(() =>
-        exec(flowBinPath, ['stop'], { cwd }).then(() =>
-          exec(flowBinPath, ['start'], { cwd })))
+      .then(() => exec(flowBinPath, ['stop'], {
+        cwd,
+      }).then(() => exec(flowBinPath, ['start'], { cwd }).catch(err => {
+        if (
+          typeof err.message === 'string' &&
+          err.message.indexOf('There is already a server running') !== -1
+        ) {
+          return true;
+        } else {
+          throw err;
+        }
+      })))
       .then(() => {
         this.flowStarted = true;
       });

From 45e6c29a5cdfb27e8cfac7948cdea2ff4f90ef3a Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Mon, 24 Apr 2017 16:32:28 -0400
Subject: [PATCH 71/74] Reduce nesting

---
 packages/react-dev-utils/FlowTypecheckPlugin.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 390d1b9802a..e0134bc9ce9 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -113,7 +113,8 @@ class FlowTypecheckPlugin {
       )
       .then(() => exec(flowBinPath, ['stop'], {
         cwd,
-      }).then(() => exec(flowBinPath, ['start'], { cwd }).catch(err => {
+      }))
+      .then(() => exec(flowBinPath, ['start'], { cwd }).catch(err => {
         if (
           typeof err.message === 'string' &&
           err.message.indexOf('There is already a server running') !== -1
@@ -122,7 +123,7 @@ class FlowTypecheckPlugin {
         } else {
           throw err;
         }
-      })))
+      }))
       .then(() => {
         this.flowStarted = true;
       });

From fb4735c106b7f17a11b76b9f0c9d3bb89e011918 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Mon, 24 Apr 2017 17:19:41 -0400
Subject: [PATCH 72/74] Simulate a mutex for startFlow

---
 .../react-dev-utils/FlowTypecheckPlugin.js     | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index e0134bc9ce9..4ee38d97c36 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -78,6 +78,7 @@ class FlowTypecheckPlugin {
   constructor() {
     this.shouldRun = false;
     this.flowStarted = false;
+    this.flowStarting = null;
 
     this.flowVersion = require(path.join(
       __dirname,
@@ -89,8 +90,16 @@ class FlowTypecheckPlugin {
     if (this.flowStarted) {
       return Promise.resolve();
     }
+    if (this.flowStarting != null) {
+      return this.flowStarting;
+    }
     console.log(chalk.cyan('Starting the flow server ...'));
     const flowConfigPath = path.join(cwd, '.flowconfig');
+    let success, fail;
+    this.flowStarting = new Promise((resolve, reject) => {
+      success = resolve;
+      fail = reject;
+    });
     return getFlowVersion(true)
       .then(globalVersion => {
         if (globalVersion === null) return;
@@ -126,6 +135,13 @@ class FlowTypecheckPlugin {
       }))
       .then(() => {
         this.flowStarted = true;
+        success();
+        this.flowStarting = null;
+      })
+      .catch(err => {
+        fail();
+        this.flowStarting = null;
+        throw err;
       });
   }
 
@@ -159,7 +175,7 @@ class FlowTypecheckPlugin {
         return;
       }
       const cwd = compiler.options.context;
-      const first = !this.flowStarted;
+      const first = this.flowStarting == null && !this.flowStarted;
       this.startFlow(cwd)
         .then(() => {
           if (first) {

From 800af94575280a4e024983bb34980200c9a4b7f9 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Wed, 3 May 2017 23:32:54 -0400
Subject: [PATCH 73/74] Fix unhandled rejection

---
 .../react-dev-utils/FlowTypecheckPlugin.js    | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/packages/react-dev-utils/FlowTypecheckPlugin.js b/packages/react-dev-utils/FlowTypecheckPlugin.js
index 4ee38d97c36..7062a350174 100644
--- a/packages/react-dev-utils/FlowTypecheckPlugin.js
+++ b/packages/react-dev-utils/FlowTypecheckPlugin.js
@@ -91,14 +91,20 @@ class FlowTypecheckPlugin {
       return Promise.resolve();
     }
     if (this.flowStarting != null) {
-      return this.flowStarting;
+      return this.flowStarting.then(err => {
+        // We need to do it like this because of unhandled rejections
+        // ... basically, we can't actually reject a promise unless someone
+        // has it handled -- which is only the case when we're returned from here
+        if (err != null) {
+          throw err;
+        }
+      });
     }
     console.log(chalk.cyan('Starting the flow server ...'));
     const flowConfigPath = path.join(cwd, '.flowconfig');
-    let success, fail;
-    this.flowStarting = new Promise((resolve, reject) => {
-      success = resolve;
-      fail = reject;
+    let delegate;
+    this.flowStarting = new Promise(resolve => {
+      delegate = resolve;
     });
     return getFlowVersion(true)
       .then(globalVersion => {
@@ -135,11 +141,11 @@ class FlowTypecheckPlugin {
       }))
       .then(() => {
         this.flowStarted = true;
-        success();
+        delegate();
         this.flowStarting = null;
       })
       .catch(err => {
-        fail();
+        delegate(err);
         this.flowStarting = null;
         throw err;
       });

From ad625f16c792e2ea7a0b571c021bcc990167610a Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Wed, 3 May 2017 23:34:19 -0400
Subject: [PATCH 74/74] Upgrade flow

---
 packages/react-dev-utils/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dev-utils/package.json b/packages/react-dev-utils/package.json
index b35129fbbc5..7ca9d4ccb7f 100644
--- a/packages/react-dev-utils/package.json
+++ b/packages/react-dev-utils/package.json
@@ -32,7 +32,7 @@
     "chalk": "1.1.3",
     "escape-string-regexp": "1.0.5",
     "filesize": "3.3.0",
-    "flow-bin": "0.44.2",
+    "flow-bin": "0.45.0",
     "gzip-size": "3.0.0",
     "html-entities": "1.2.0",
     "opn": "4.0.2",