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Collection of library stubs for Python, with static types
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Disable mypy overload-overlap warnings? #12178

Open srittau opened 2 weeks ago

srittau commented 2 weeks ago

These mypy warnings are overzealous, as it's often quite useful to have partial overlaps: We ignore this warning in 192 places in typeshed at the moment, and I don't think we gain any benefit from having it enabled.

Ideally, mypy would have a separate warning for overloads that are completely shadowed by another overload, though.

AlexWaygood commented 2 weeks ago

We should check how many become unused with the mypy master branch, as the way the lint works at mypy has just been completely reworked in https://github.com/python/mypy/pull/17392.

srittau commented 2 weeks ago

That sounds promising!

AlexWaygood commented 2 weeks ago

So yes, these are mypy's new complaints regarding overload-overlap if you use mypy master, fiddle with mypy's master branch so that you get rid of the thing where it stops --warn-unused-ignores from working inside typeshed directories, then fiddle with our mypy_test.py so that it ignores the override error code (because there's a bunch of new errors from that error code on mypy master which are unrelated to the thing we're discussing here), and then run python tests/mypy_test.py stdlib -p3.13:

``` stdlib/typing.pyi:1056: error: Unused "type: ignore" comment [unused-ignore] stdlib/types.pyi:322: error: Unused "type: ignore" comment [unused-ignore] stdlib/types.pyi:573: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:77: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:127: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:133: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:139: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:158: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:164: error: Unused "type: ignore" comment [unused-ignore] stdlib/re.pyi:175: error: Unused "type: ignore" comment [unused-ignore] stdlib/importlib/metadata/__init__.pyi:49: error: Unused "type: ignore" comment [unused-ignore] stdlib/enum.pyi:108: error: Unused "type: ignore" comment [unused-ignore] stdlib/enum.pyi:244: error: Unused "type: ignore" comment [unused-ignore] stdlib/collections/__init__.pyi:289: error: Unused "type: ignore" comment [unused-ignore] stdlib/builtins.pyi:171: error: Unused "type: ignore" comment [unused-ignore] stdlib/builtins.pyi:1735: error: Unused "type: ignore" comment [unused-ignore] stdlib/builtins.pyi:1745: error: Unused "type: ignore" comment [unused-ignore] stdlib/tempfile.pyi:464: error: Unused "type: ignore" comment [unused-ignore] stdlib/tempfile.pyi:474: error: Unused "type: ignore" comment [unused-ignore] stdlib/urllib/parse.pyi:201: error: Overloaded function signatures 1 and 2 overlap with incompatible return types [overload-overlap] stdlib/urllib/parse.pyi:207: error: Overloaded function signatures 1 and 2 overlap with incompatible return types [overload-overlap] stdlib/unittest/mock.pyi:278: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:339: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:385: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:396: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:620: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:659: error: Unused "type: ignore" comment [unused-ignore] stdlib/turtle.pyi:669: error: Unused "type: ignore" comment [unused-ignore] stdlib/tkinter/ttk.pyi:1043: error: Unused "type: ignore" comment [unused-ignore] stdlib/tkinter/ttk.pyi:1087: error: Unused "type: ignore" comment [unused-ignore] stdlib/urllib/error.pyi:17: error: Unused "type: ignore" comment [unused-ignore] stdlib/multiprocessing/sharedctypes.pyi:76: error: Unused "type: ignore" comment [unused-ignore] stdlib/multiprocessing/sharedctypes.pyi:118: error: Unused "type: ignore" comment [unused-ignore] stdlib/multiprocessing/sharedctypes.pyi:122: error: Unused "type: ignore" comment [unused-ignore] stdlib/multiprocessing/sharedctypes.pyi:123: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:151: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:153: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:157: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:166: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:176: error: Unused "type: ignore" comment [unused-ignore] stdlib/asyncio/tasks.pyi:189: error: Unused "type: ignore" comment [unused-ignore] ```

And in our third-party stubs we have:

``` stubs/WebOb/webob/request.pyi:44: error: Unused "type: ignore" comment [unused-ignore] stubs/gevent/gevent/timeout.pyi:46: error: Unused "type: ignore" comment [unused-ignore] stubs/icalendar/icalendar/parser_tools.pyi:11: error: Unused "type: ignore" comment [unused-ignore] stubs/icalendar/icalendar/parser_tools.pyi:15: error: Unused "type: ignore" comment [unused-ignore] stubs/olefile/olefile/olefile.pyi:168: error: Unused "type: ignore" comment [unused-ignore] stubs/olefile/olefile/olefile.pyi:170: error: Unused "type: ignore" comment [unused-ignore] stubs/openpyxl/openpyxl/xml/_functions_overloads.pyi:80: error: Unused "type: ignore" comment [unused-ignore] stubs/openpyxl/openpyxl/descriptors/nested.pyi:40: error: Unused "type: ignore" comment [unused-ignore] stubs/openpyxl/openpyxl/descriptors/nested.pyi:158: error: Unused "type: ignore" comment [unused-ignore] stubs/openpyxl/openpyxl/descriptors/nested.pyi:274: error: Unused "type: ignore" comment [unused-ignore] stubs/pika/pika/adapters/twisted_connection.pyi:26: error: Unused "type: ignore" comment [unused-ignore] stubs/pika/pika/adapters/twisted_connection.pyi:27: error: Unused "type: ignore" comment [unused-ignore] stubs/pycocotools/pycocotools/mask.pyi:25: error: Unused "type: ignore" comment [unused-ignore] stubs/setuptools/pkg_resources/__init__.pyi:127: error: Unused "type: ignore" comment [unused-ignore] stubs/setuptools/pkg_resources/__init__.pyi:136: error: Unused "type: ignore" comment [unused-ignore] stubs/setuptools/pkg_resources/__init__.pyi:155: error: Unused "type: ignore" comment [unused-ignore] stubs/setuptools/pkg_resources/__init__.pyi:159: error: Unused "type: ignore" comment [unused-ignore] stubs/setuptools/pkg_resources/__init__.pyi:196: error: Unused "type: ignore" comment [unused-ignore] stubs/ExifRead/exifread/utils.pyi:9: error: Unused "type: ignore" comment [unused-ignore] ```

So in total that's around 60 that will go away altogether. That will still leave us with quite a few errors ignored in typeshed, and I agree we don't get much value from the check. (We already have pyright's version switched off, because it was even noisier than mypy's.)

Diff I made to mypy to get --warn-unused-ignore working:

```diff --- a/mypy/errors.py +++ b/mypy/errors.py @@ -680,11 +680,6 @@ class Errors: self.has_blockers.remove(path) def generate_unused_ignore_errors(self, file: str) -> None: - if ( - is_typeshed_file(self.options.abs_custom_typeshed_dir if self.options else None, file) - or file in self.ignored_files - ): - return ignored_lines = self.ignored_lines[file] used_ignored_lines = self.used_ignored_lines[file] for line, ignored_codes in ignored_lines.items(): ```

Diff I made to our tests:

```diff diff --git a/tests/mypy_test.py b/tests/mypy_test.py index cafaca811..431439509 100755 --- a/tests/mypy_test.py +++ b/tests/mypy_test.py @@ -270,6 +270,8 @@ def run_mypy( "ignore-without-code", "--enable-error-code", "redundant-self", + "--disable-error-code", + "override", "--config-file", temp.name, ] ```
srittau commented 2 weeks ago

My gut feeling says that we should disable the test even after the PR (as you also wrote), but maybe it's a good idea to do this after the next mypy release, as a baseline.