The Final patch

.editorconfig

@@ -1,11 +1,11 @@
 root = true
 
-[*.{py,c,cpp,h,rst,md,yml,json}]
+[*.{py,c,cpp,h,rst,md,yml,json,test}]
 trim_trailing_whitespace = true
 insert_final_newline = true
 indent_style = space
 
-[*.{py,c,h,json}]
+[*.{py,c,h,json,test}]
 indent_size = 4
 
 [*.yml]

.github/workflows/docs.yml

@@ -23,7 +23,7 @@ jobs:
         with:
           python-version: '3.7'
       - name: Install tox
-        run: pip install --upgrade 'setuptools!=50' 'virtualenv<16.7.11' tox==3.20.1
+        run: pip install --upgrade 'setuptools!=50' 'virtualenv>=20.6.0' tox==3.24.5
       - name: Setup tox environment
         run: tox -e ${{ env.TOXENV }} --notest
       - name: Test

.github/workflows/mypy_primer.yml

@@ -8,6 +8,10 @@ on:
     - '**/*.rst'
     - '**/*.md'
     - 'mypyc/**'
+    - 'mypy/stubtest.py'
+    - 'mypy/stubgen.py'
+    - 'mypy/stubgenc.py'
+    - 'mypy/test/**'
 
 jobs:
   mypy_primer:

.github/workflows/mypy_primer_comment.yml

@@ -38,62 +38,41 @@ jobs:
             fs.writeFileSync("diff.zip", Buffer.from(download.data));
 
       - run: unzip diff.zip
-
-      # Based on https://github.com/kanga333/comment-hider
-      - name: Hide old comments
-        uses: actions/github-script@v3
-        with:
-          github-token: ${{secrets.GITHUB_TOKEN}}
-          script: |
-            const fs = require('fs')
-
-            const response = await github.issues.listComments({
-              issue_number: fs.readFileSync("pr_number.txt", { encoding: "utf8" }),
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-            })
-            const botCommentIds = response.data
-              .filter(comment => comment.user.login === 'github-actions[bot]')
-              .map(comment => comment.node_id)
-
-            for (const id of botCommentIds) {
-              const resp = await github.graphql(`
-                mutation {
-                  minimizeComment(input: {classifier: OUTDATED, subjectId: "${id}"}) {
-                    minimizedComment {
-                      isMinimized
-                    }
-                  }
-                }
-              `)
-              if (resp.errors) {
-                throw new Error(resp.errors)
-              }
-            }
+      # 30000 bytes is about 300 lines, posting comment fails if too long
+      - run: |
+          cat diff_*.txt | head -c 30000 | tee fulldiff.txt
 
       - name: Post comment
+        id: post-comment
         uses: actions/github-script@v3
         with:
-          github-token: ${{secrets.GITHUB_TOKEN}}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
             const fs = require('fs')
-            // Keep in sync with shards produced by mypy_primer workflow
-            const data = (
-              ['diff_0.txt', 'diff_1.txt', 'diff_2.txt']
-              .map(fileName => fs.readFileSync(fileName, { encoding: 'utf8' }))
-              .join('')
-              .substr(0, 30000)  // About 300 lines
-            )
+            const data = fs.readFileSync('fulldiff.txt', { encoding: 'utf8' })
 
             console.log("Diff from mypy_primer:")
             console.log(data)
 
+            let body
             if (data.trim()) {
-              const body = 'Diff from [mypy_primer](https://github.com/hauntsaninja/mypy_primer), showing the effect of this PR on open source code:\n```diff\n' + data + '```'
-              await github.issues.createComment({
-                issue_number: fs.readFileSync("pr_number.txt", { encoding: "utf8" }),
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                body
-              })
+              body = 'Diff from [mypy_primer](https://github.com/hauntsaninja/mypy_primer), showing the effect of this PR on open source code:\n```diff\n' + data + '```'
+            } else {
+              body = 'According to [mypy_primer](https://github.com/hauntsaninja/mypy_primer), this change has no effect on the checked open source code. 🤖🎉'
             }
+            const prNumber = parseInt(fs.readFileSync("pr_number.txt", { encoding: "utf8" }))
+            await github.issues.createComment({
+              issue_number: prNumber,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body
+            })
+            return prNumber
+
+      - name: Hide old comments
+        # v0.3.0
+        uses: kanga333/comment-hider@bbdf5b562fbec24e6f60572d8f712017428b92e0
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          leave_visible: 1
+          issue_number: ${{ steps.post-comment.outputs.result }}

.github/workflows/test.yml

@@ -75,11 +75,16 @@ jobs:
           toxenv: py36
           tox_extra_args: "-n 2 mypyc/test/test_run.py mypyc/test/test_external.py"
           debug_build: true
-        - name: Type check our own code
+        - name: Type check our own code (py37-ubuntu)
           python: '3.7'
           arch: x64
           os: ubuntu-latest
           toxenv: type
+        - name: Type check our own code (py37-windows-64)
+          python: '3.7'
+          arch: x64
+          os: windows-latest
+          toxenv: type
         - name: Code style with flake8
           python: '3.7'
           arch: x64
@@ -102,7 +107,7 @@ jobs:
         ./misc/build-debug-python.sh $PYTHONVERSION $PYTHONDIR $VENV
         source $VENV/bin/activate
     - name: Install tox
-      run: pip install --upgrade 'setuptools!=50' 'virtualenv>=20.6.0' tox==3.20.1
+      run: pip install --upgrade 'setuptools!=50' 'virtualenv>=20.6.0' tox==3.24.5
     - name: Compiled with mypyc
       if: ${{ matrix.test_mypyc }}
       run: |

CONTRIBUTING.md

@@ -54,6 +54,12 @@ You can also use `tox` to run tests, for instance:
 tox -e py
 ```
 
+The easiest way to run a single test is:
+```
+pytest -n0 -k 'test_name'
+```
+There's more useful information on writing and running tests [here](test-data/unit/README.md)
+
 ## First time contributors
 
 If you're looking for things to help with, browse our [issue tracker](https://github.com/python/mypy/issues)!
@@ -63,21 +69,24 @@ In particular, look for:
 - [good second issues](https://github.com/python/mypy/labels/good-second-issue)
 - [documentation issues](https://github.com/python/mypy/labels/documentation)
 
-It's also extremely easy to get started contributing to our sister project
-[typeshed](https://github.com/python/typeshed/issues) that provides type stubs
-for libraries. This is a great way to become familiar with type syntax.
-
-If you need help getting started, don't hesitate to ask on
-[gitter](https://gitter.im/python/typing).
+You do not need to ask for permission to work on any of these issues.
+Just fix the issue yourself, [try to add a unit test](#running-tests) and
+[open a pull request](#submitting-changes).
 
 To get help fixing a specific issue, it's often best to comment on the issue
-itself. The more details you provide about what you've tried and where you've
-looked, the easier it will be for you to get help.
+itself. You're much more likely to get help if you provide details about what
+you've tried and where you've looked (maintainers tend to help those who help
+themselves). [gitter](https://gitter.im/python/typing) can also be a good place
+to ask for help.
 
 Interactive debuggers like `pdb` and `ipdb` are really useful for getting
 started with the mypy codebase. This is a
 [useful tutorial](https://realpython.com/python-debugging-pdb/).
 
+It's also extremely easy to get started contributing to our sister project
+[typeshed](https://github.com/python/typeshed/issues) that provides type stubs
+for libraries. This is a great way to become familiar with type syntax.
+
 ## Submitting changes
 
 Even more excellent than a good bug report is a fix for a bug, or the

CREDITS

@@ -11,15 +11,18 @@ Dropbox core team:
 
   Jukka Lehtosalo <[email protected]>
   Ivan Levkivskyi <[email protected]>
+  Jared Hance
 
 Non-Dropbox core team members:
 
   Ethan Smith
   Guido van Rossum <[email protected]>
-  Jelle Zijlstra
+  Jelle Zijlstra <[email protected]>
   Michael J. Sullivan <[email protected]>
   Shantanu Jain
-  Xuanda Yang
+  Xuanda Yang <[email protected]>
+  Jingchen Ye <[email protected]>
+  Nikita Sobolev <[email protected]>
 
 Past Dropbox core team members:
 

LICENSE

@@ -4,7 +4,8 @@ Mypy (and mypyc) are licensed under the terms of the MIT license, reproduced bel
 
 The MIT License
 
-Copyright (c) 2015-2021 Jukka Lehtosalo and contributors
+Copyright (c) 2012-2022 Jukka Lehtosalo and contributors
+Copyright (c) 2015-2022 Dropbox, Inc.
 
 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),

docs/source/command_line.rst

@@ -524,7 +524,16 @@ of the above sections.
            # 'items' has type list[str]
            items = [item.split() for item in items]
            # 'items' now has type list[list[str]]
-           ...
+
+    The variable must be used before it can be redefined:
+
+    .. code-block:: python
+
+        def process(items: list[str]) -> None:
+           items = "mypy"  # invalid redefinition to str because the variable hasn't been used yet
+           print(items)
+           items = "100"  # valid, items now has type str
+           items = int(items)  # valid, items now has type int
 
 .. option:: --local-partial-types
 

docs/source/config_file.rst

@@ -201,7 +201,7 @@ section of the command line docs.
 
     A regular expression that matches file names, directory names and paths
     which mypy should ignore while recursively discovering files to check.
-    Use forward slashes on all platforms.
+    Use forward slashes (``/``) as directory separators on all platforms.
 
     .. code-block:: ini
 
@@ -237,8 +237,9 @@ section of the command line docs.
 
           [tool.mypy]
           exclude = [
-            "^file1\\.py$",  # TOML's double-quoted strings require escaping backslashes
-            '^file2\.py$',  # but TOML's single-quoted strings do not
+              "^one\\.py$",  # TOML's double-quoted strings require escaping backslashes
+              'two\.pyi$',  # but TOML's single-quoted strings do not
+              '^three\.',
           ]
 
        A single, multi-line string:
@@ -247,9 +248,10 @@ section of the command line docs.
 
           [tool.mypy]
           exclude = '''(?x)(
-              ^file1\.py$
-              |^file2\.py$,
-          )'''
+              ^one\.py$    # files named "one.py"
+              | two\.pyi$  # or files ending with "two.pyi"
+              | ^three\.   # or files starting with "three."
+          )'''  # TOML's single-quoted strings do not require escaping backslashes
 
        See :ref:`using-a-pyproject-toml`.
 
@@ -613,6 +615,24 @@ section of the command line docs.
 
     Allows variables to be redefined with an arbitrary type, as long as the redefinition
     is in the same block and nesting level as the original definition.
+    Example where this can be useful:
+
+    .. code-block:: python
+
+       def process(items: list[str]) -> None:
+           # 'items' has type list[str]
+           items = [item.split() for item in items]
+           # 'items' now has type list[list[str]]
+
+    The variable must be used before it can be redefined:
+
+    .. code-block:: python
+
+        def process(items: list[str]) -> None:
+           items = "mypy"  # invalid redefinition to str because the variable hasn't been used yet
+           print(items)
+           items = "100"  # valid, items now has type str
+           items = int(items)  # valid, items now has type int
 
 .. confval:: local_partial_types
 

docs/source/error_code_list2.rst

@@ -255,3 +255,36 @@ no error in practice. In such case, it might be prudent to annotate ``items: Seq
 This is similar in concept to ensuring that an expression's type implements an expected interface (e.g. ``Sized``),
 except that attempting to invoke an undefined method (e.g. ``__len__``) results in an error,
 while attempting to evaluate an object in boolean context without a concrete implementation results in a truthy value.
+
+
+.. _ignore-without-code:
+
+Check that ``# type: ignore`` include an error code [ignore-without-code]
+-------------------------------------------------------------------------
+
+Warn when a ``# type: ignore`` comment does not specify any error codes.
+This clarifies the intent of the ignore and ensures that only the
+expected errors are silenced.
+
+Example:
+
+.. code-block:: python
+
+    # mypy: enable-error-code ignore-without-code
+
+    class Foo:
+        def __init__(self, name: str) -> None:
+            self.name = name
+
+    f = Foo('foo')
+
+    # This line has a typo that mypy can't help with as both:
+    # - the expected error 'assignment', and
+    # - the unexpected error 'attr-defined'
+    # are silenced.
+    # Error: "type: ignore" comment without error code (consider "type: ignore[attr-defined]" instead)
+    f.nme = 42  # type: ignore
+
+    # This line warns correctly about the typo in the attribute name
+    # Error: "Foo" has no attribute "nme"; maybe "name"?
+    f.nme = 42  # type: ignore[assignment]

docs/source/error_codes.rst

@@ -31,6 +31,10 @@ or config `show_error_codes = True` to display error codes. Error codes are show
    $ mypy --show-error-codes prog.py
    prog.py:1: error: "str" has no attribute "trim"  [attr-defined]
 
+It's also possible to require error codes for ``type: ignore`` comments.
+See :ref:`ignore-without-code<ignore-without-code>` for more information.
+
+
 .. _silence-error-codes:
 
 Silencing errors based on error codes

docs/source/generics.rst

@@ -673,6 +673,10 @@ protocols mostly follow the normal rules for generic classes. Example:
    y: Box[int] = ...
    x = y  # Error -- Box is invariant
 
+Per :pep:`PEP 544: Generic protocols <544#generic-protocols>`, ``class
+ClassName(Protocol[T])`` is allowed as a shorthand for ``class
+ClassName(Protocol, Generic[T])``.
+
 The main difference between generic protocols and ordinary generic
 classes is that mypy checks that the declared variances of generic
 type variables in a protocol match how they are used in the protocol