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[ty] Implement implicit inheritance from Generic[] for PEP-695 generic classes #18283

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Merged
merged 2 commits into from
May 26, 2025
Merged

[ty] Implement implicit inheritance from Generic[] for PEP-695 generic classes #18283

merged 2 commits into from
May 26, 2025

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AlexWaygood
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Summary

PEP-695 classes have Generic implicitly appended to the end of their __bases__:

>>> class Foo[T]: ...
... 
>>> Foo.__mro__
(<class '__main__.Foo'>, <class 'typing.Generic'>, <class 'object'>)
>>> class Bar[T](int): ...
... 
>>> Bar.__mro__
(<class '__main__.Bar'>, <class 'int'>, <class 'typing.Generic'>, <class 'object'>)

This isn't something we fully model on main, leading us to infer inaccurate MROs for PEP-695 generic classes in some situations. This PR fixes that.

Test Plan

mdtests

@AlexWaygood AlexWaygood added the ty Multi-file analysis & type inference label May 23, 2025
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github-actions bot commented May 23, 2025 •
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mypy_primer results

Changes were detected when running on open source projects 
pytest-robotframework (https://github.com/detachhead/pytest-robotframework)
- error[invalid-argument-type] pytest_robotframework/_internal/robot/utils.py:158:15: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] pytest_robotframework/_internal/robot/utils.py:158:15: `Unknown` is not a valid argument to `Generic`

starlette (https://github.com/encode/starlette)
- error[invalid-argument-type] starlette/middleware/__init__.py:17:26: `ParamSpec` is not a valid argument to subscripted `typing.Protocol`
+ error[invalid-argument-type] starlette/middleware/__init__.py:17:26: `ParamSpec` is not a valid argument to `Protocol`

comtypes (https://github.com/enthought/comtypes)
- error[invalid-argument-type] comtypes/hints.pyi:150:33: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:150:33: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] comtypes/hints.pyi:160:28: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:160:28: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] comtypes/hints.pyi:174:34: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:174:34: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] comtypes/hints.pyi:183:29: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:183:29: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] comtypes/hints.pyi:196:34: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:196:34: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] comtypes/hints.pyi:205:29: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] comtypes/hints.pyi:205:29: `ParamSpec` is not a valid argument to `Generic`

asynq (https://github.com/quora/asynq)
- error[invalid-argument-type] asynq/decorators.pyi:35:70: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] asynq/decorators.pyi:35:70: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] asynq/decorators.pyi:39:58: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] asynq/decorators.pyi:39:58: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] asynq/decorators.pyi:70:62: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] asynq/decorators.pyi:70:62: `ParamSpec` is not a valid argument to `Generic`

hydra-zen (https://github.com/mit-ll-responsible-ai/hydra-zen)
- error[invalid-argument-type] src/hydra_zen/typing/_implementations.py:139:32: `ParamSpec` is not a valid argument to subscripted `typing.Protocol`
+ error[invalid-argument-type] src/hydra_zen/typing/_implementations.py:139:32: `ParamSpec` is not a valid argument to `Protocol`
- error[invalid-argument-type] src/hydra_zen/wrapper/_implementations.py:110:11: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] src/hydra_zen/wrapper/_implementations.py:110:11: `ParamSpec` is not a valid argument to `Generic`

psycopg (https://github.com/psycopg/psycopg)
- error[invalid-argument-type] psycopg_pool/psycopg_pool/pool.py:38:22: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] psycopg_pool/psycopg_pool/pool.py:38:22: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] psycopg_pool/psycopg_pool/pool.py:814:21: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] psycopg_pool/psycopg_pool/pool.py:814:21: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] psycopg_pool/psycopg_pool/pool_async.py:38:27: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] psycopg_pool/psycopg_pool/pool_async.py:38:27: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] psycopg_pool/psycopg_pool/pool_async.py:868:21: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] psycopg_pool/psycopg_pool/pool_async.py:868:21: `Unknown` is not a valid argument to `Generic`

Expression (https://github.com/cognitedata/Expression)
- error[invalid-argument-type] expression/core/fn.py:14:16: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] expression/core/fn.py:14:16: `ParamSpec` is not a valid argument to `Generic`

mkdocs (https://github.com/mkdocs/mkdocs)
- error[invalid-argument-type] mkdocs/plugins.py:460:21: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mkdocs/plugins.py:460:21: `ParamSpec` is not a valid argument to `Generic`

mitmproxy (https://github.com/mitmproxy/mitmproxy)
- error[invalid-argument-type] mitmproxy/utils/signals.py:68:19: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mitmproxy/utils/signals.py:68:19: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] mitmproxy/utils/signals.py:81:20: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mitmproxy/utils/signals.py:81:20: `ParamSpec` is not a valid argument to `Generic`

static-frame (https://github.com/static-frame/static-frame)
- error[invalid-argument-type] static_frame/core/frame.py:239:31: `@Todo(Inference of subscript on special form)` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] static_frame/core/frame.py:239:31: `@Todo(Inference of subscript on special form)` is not a valid argument to `Generic`
- error[invalid-argument-type] static_frame/core/index_hierarchy.py:234:33: `@Todo(Inference of subscript on special form)` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] static_frame/core/index_hierarchy.py:234:33: `@Todo(Inference of subscript on special form)` is not a valid argument to `Generic`

mypy (https://github.com/python/mypy)
- error[invalid-argument-type] mypy/typeshed/stdlib/asyncio/tasks.pyi:431:34: `Unknown` is not a valid argument to subscripted `typing.Protocol`
+ error[invalid-argument-type] mypy/typeshed/stdlib/asyncio/tasks.pyi:431:34: `Unknown` is not a valid argument to `Protocol`
- error[invalid-argument-type] mypy/typeshed/stdlib/asyncio/tasks.pyi:443:33: `Unknown` is not a valid argument to subscripted `typing.Protocol`
+ error[invalid-argument-type] mypy/typeshed/stdlib/asyncio/tasks.pyi:443:33: `Unknown` is not a valid argument to `Protocol`
- error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:139:20: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:139:20: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:156:19: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:156:19: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:1999:45: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/builtins.pyi:1999:45: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/contextlib.pyi:214:53: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/contextlib.pyi:214:53: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/functools.pyi:86:16: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/functools.pyi:86:16: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/functools.pyi:93:16: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/functools.pyi:93:16: `ParamSpec` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/unittest/case.pyi:73:52: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/unittest/case.pyi:73:52: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] mypy/typeshed/stdlib/weakref.pyi:189:16: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] mypy/typeshed/stdlib/weakref.pyi:189:16: `ParamSpec` is not a valid argument to `Generic`

streamlit (https://github.com/streamlit/streamlit)
- error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:94:25: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:94:25: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:117:26: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:117:26: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:153:24: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/button_group.py:153:24: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/multiselect.py:65:24: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/multiselect.py:65:24: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/radio.py:61:18: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/radio.py:61:18: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/select_slider.py:76:25: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/select_slider.py:76:25: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/elements/widgets/selectbox.py:64:22: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/elements/widgets/selectbox.py:64:22: `Unknown` is not a valid argument to `Generic`
- error[invalid-argument-type] lib/streamlit/testing/v1/element_tree.py:1120:22: `Unknown` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] lib/streamlit/testing/v1/element_tree.py:1120:22: `Unknown` is not a valid argument to `Generic`

zulip (https://github.com/zulip/zulip)
- error[invalid-argument-type] zerver/lib/cache.py:745:39: `ParamSpec` is not a valid argument to `typing.Generic`
+ error[invalid-argument-type] zerver/lib/cache.py:745:39: `ParamSpec` is not a valid argument to `Generic`

dcreager
dcreager approved these changes May 24, 2025
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Excellent, thank you for catching this!

@AlexWaygood AlexWaygood force-pushed the alex/695-generic-base branch from c167e47 to d8a1519 Compare May 26, 2025 19:27
@AlexWaygood
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This change means that we now naturally recognize classes such as class Foo[T](Generic[T]): ... at MRO-resolution time, so I was able to reimplement the diagnostic telling users off for doing that as an MroError variant. This enabled me to push some simplifications to the GenericContext struct (we no longer need to record whether the context came from typing.Generic or typing.Protocol inheritance), which in turn has led to some small speedups in the benchmarks 🎉 https://codspeed.io/astral-sh/ruff/branches/alex%2F695-generic-base

@AlexWaygood AlexWaygood merged commit 0a11baf into main May 26, 2025
35 checks passed
@AlexWaygood AlexWaygood deleted the alex/695-generic-base branch May 26, 2025 19:40
carljm added a commit to MatthewMckee4/ruff that referenced this pull request May 28, 2025
@carljm
Merge branch 'main' into class-literal-init-callable-subtyping
c1bb91d 
* main: (246 commits)
  [ty] Simplify signature types, use them in `CallableType` (astral-sh#18344)
  [ty] Support ephemeral uv virtual environments (astral-sh#18335)
  Add a `ViolationMetadata::rule` method (astral-sh#18234)
  Return `DiagnosticGuard` from `Checker::report_diagnostic` (astral-sh#18232)
  [flake8_use_pathlib]: Replace os.symlink with Path.symlink_to (PTH211) (astral-sh#18337)
  [ty] Support cancellation and retry in the server (astral-sh#18273)
  [ty] Synthetic function-like callables (astral-sh#18242)
  [ty] Support publishing diagnostics in the server (astral-sh#18309)
  Add Autofix for ISC003 (astral-sh#18256)
  [`pyupgrade`]: new rule UP050 (`useless-class-metaclass-type`) (astral-sh#18334)
  [pycodestyle] Make `E712` suggestion not assume a context (astral-sh#18328)
  put similar dunder-call tests next to each other (astral-sh#18343)
  [ty] Derive `PartialOrd, Ord` for `KnownInstanceType` (astral-sh#18340)
  [ty] Simplify `Type::try_bool()` (astral-sh#18342)
  [ty] Simplify `Type::normalized` slightly (astral-sh#18339)
  [ty] Move arviz off the list of selected primer projects (astral-sh#18336)
  [ty] Add --config-file CLI arg (astral-sh#18083)
  [ty] Tell the user why we inferred a certain Python version when reporting version-specific syntax errors (astral-sh#18295)
  [ty] Implement implicit inheritance from `Generic[]` for PEP-695 generic classes (astral-sh#18283)
  [ty] Add hint if async context manager is used in non-async with statement (astral-sh#18299)
  ...
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@dcreager dcreager dcreager approved these changes

@carljm carljm Awaiting requested review from carljm carljm is a code owner

@sharkdp sharkdp Awaiting requested review from sharkdp sharkdp is a code owner

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