Skip to content

Fix Enum.value inference for Enums with @cached methods #19374

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: master
Choose a base branch
from

Conversation

kmurphy4
Copy link

@kmurphy4 kmurphy4 commented Jul 4, 2025

Before this, adding an annotation like @functools.cache to any method on an Enum caused the inference for the class's .value to fail (i.e., become Any).

Fixes #19368

Before this, adding an annotation like `@functools.cache` to any
method on an `Enum` caused the inference for the class's `.value`
to fail (i.e., become `Any`).

Fixes python#19368

Co-authored-by: Stanislav Terliakov <[email protected]>
@kmurphy4
Copy link
Author

kmurphy4 commented Jul 4, 2025

Should I add something to the changelog? I think this is a user-facing change.

Copy link
Contributor

github-actions bot commented Jul 4, 2025

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅

@sterliakov
Copy link
Collaborator

We build changelog from the commit history, like #19138, so no need to add CHANGELOG entries in every PR:)

@@ -194,12 +194,7 @@ class SomeEnum:
for n in stnodes
if n is None or not n.implicit
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not sure this check is still needed - can there be any enum_members that are implicit? That should never happen AFAIC

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Seems like it is? With

diff --git i/mypy/plugins/enums.py w/mypy/plugins/enums.py
index 35338d091..c6e9f21b6 100644
--- i/mypy/plugins/enums.py
+++ w/mypy/plugins/enums.py
@@ -192,7 +192,7 @@ def enum_value_callback(ctx: mypy.plugin.AttributeContext) -> Type:
             node_types = (
                 get_proper_type(n.type) if n else None
                 for n in stnodes
-                if n is None or not n.implicit
+                if n is None
             )
             proper_types = [_infer_value_type_with_auto_fallback(ctx, t) for t in node_types]
             underlying_type = _first(proper_types)

I get

$ pytest -k testValueFallbackWithCachedMethod
============================= test session starts ==============================
platform linux -- Python 3.12.6, pytest-8.3.5, pluggy-1.6.0
rootdir: /home/kevinmurphy/src/python/mypy
configfile: pyproject.toml
testpaths: mypy/test, mypyc/test
plugins: xdist-3.7.0, cov-6.1.1
6 workers [1 item]      
F                                                                        [100%]
=================================== FAILURES ===================================
______________________ testValueFallbackWithCachedMethod _______________________
[gw0] linux -- Python 3.12.6 /home/kevinmurphy/src/python/mypy/venv/bin/python3
data: /home/kevinmurphy/src/python/mypy/test-data/unit/check-enum.test:2543:
Failed: Unexpected type checker output (/home/kevinmurphy/src/python/mypy/test-data/unit/check-enum.test, line 2543)
----------------------------- Captured stderr call -----------------------------
Expected:
  main:19: note: Revealed type is "builtins.int"
  main:22: note: Revealed type is "builtins.int" (diff)
Actual:
  main:19: note: Revealed type is "builtins.int"
  main:22: note: Revealed type is "Any" (diff)

Alignment of first line difference:
  E: ...ote: Revealed type is "builtins.int"
  A: ...ote: Revealed type is "Any"
                               ^
Update the test output using --update-data (implies -n0; you can additionally use the -k selector to update only specific tests)
=========================== short test summary info ============================
FAILED mypy/test/testcheck.py::TypeCheckSuite::check-enum.test::testValueFallbackWithCachedMethod
============================== 1 failed in 2.26s ===============================

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

Enum.value typed as Any when using functools.cache
2 participants