Issue mozilla-mobile#34: Add a way to enforce specific lints.

Before this commits no lints would actually fail the build because we only
checked for compatibility.

After this commit apilint runs the lint twice:

- Once with only the existing api as argument to check for lints (with an
  optional filter for lints).

- Once with both existing and new API to check for compatibility.

This adds a new configuration: `apiLint.lintFilters` which allows consumers to
set a list of prefixes of lints that can fail the build.

README.md

@@ -105,6 +105,7 @@ apiLint {
     currentApiRelativeFilePath = 'api.txt'
     jsonResultFileName = 'apilint-result.json'
     changelogFileName = null
+    lintFilters = null
 }
 ```
 
@@ -122,3 +123,7 @@ contains the result of apilint.
 
 <code><b>changelogFileName</b></code> Relative path to the changelog file,
 optional. See also [Changelog](#changelog).
+
+<code><b>lintFilters</b></code> List of lints that fail the build, by default
+all lints can fail the build. Filters will match any error code that starts
+with the string specified, e.g. `GV` will match `GV1`, `GV2`, ...

apilint/src/main/groovy/org/mozilla/apilint/ApiLintPlugin.groovy

@@ -45,20 +45,36 @@ class ApiLintPlugin implements Plugin<Project> {
 
             apiGenerate.dependsOn variant.javaCompile
 
+            def apiCompatLint = project.task("apiCompatLint${name}", type: PythonExec) {
+                description = "Runs API compatibility lint checks for variant ${name}"
+                workingDir '.'
+                scriptPath 'apilint.py'
+                args '--show-noticed'
+                args apiFile
+                args currentApiFile
+                args '--result-json'
+                args project.file(
+                        "${variant.javaCompile.destinationDir}/${extension.jsonResultFileName}")
+            }
+
+            apiCompatLint.dependsOn apiGenerate
+
             def apiLint = project.task("apiLint${name}", type: PythonExec) {
                 description = "Runs API lint checks for variant ${name}"
                 group = 'Verification'
                 workingDir '.'
                 scriptPath 'apilint.py'
-                args '--show-noticed'
-                args apiFile
                 args currentApiFile
                 args '--result-json'
                 args project.file(
                         "${variant.javaCompile.destinationDir}/${extension.jsonResultFileName}")
+                if (extension.lintFilters != null) {
+                    args '--filter-errors'
+                    args extension.lintFilters
+                }
             }
 
-            apiLint.dependsOn apiGenerate
+            apiLint.dependsOn apiCompatLint
             project.tasks.check.dependsOn apiLint
 
             if (extension.changelogFileName) {
@@ -74,7 +90,7 @@ class ApiLintPlugin implements Plugin<Project> {
                 }
 
                 apiChangelogCheck.dependsOn apiGenerate
-                apiLint.dependsOn apiChangelogCheck
+                apiCompatLint.dependsOn apiChangelogCheck
             }
 
             def apiDiff = project.task("apiDiff${name}", type: Exec) {
@@ -107,7 +123,7 @@ class ApiLintPlugin implements Plugin<Project> {
             }
 
             apiLintHelp.dependsOn apiDiff
-            apiLint.finalizedBy apiLintHelp
+            apiCompatLint.finalizedBy apiLintHelp
 
             def apiUpdate = project.task("apiUpdateFile${name}", type: Copy) {
                 description = "Updates the API file from the local one for variant ${name}"

apilint/src/main/groovy/org/mozilla/apilint/ApiLintPluginExtension.groovy

@@ -8,4 +8,5 @@ class ApiLintPluginExtension {
     String currentApiRelativeFilePath = 'api.txt'
     String jsonResultFileName = 'apilint-result.json'
     String changelogFileName
+    List<String> lintFilters
 }

apilint/src/main/resources/apilint.py

@@ -1651,7 +1651,8 @@ def matches_filter(filter_, failure):
                 filtered_fail[p] = cur_fail[p]
         cur_fail = filtered_fail
 
-    dump_result_json(args, compat_fail, cur_noticed, cur_fail)
+    dump_result_json(args, compat_fail,
+        cur_noticed if args['show_noticed'] else [], cur_fail)
 
     if compat_fail and len(compat_fail) != 0:
         print("%s API compatibility issues %s\n" % ((format(fg=WHITE, bg=BLUE, bold=True), format(reset=True))))