overload and contextmanager doesn't work together
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Description
Bug Report
contextmanager and overload doesn't seem to be compatbile together
To Reproduce
from contextlib import contextmanager
from typing import overload, ContextManager, Iterator
from uuid import UUID
@overload
def cactus() -> ContextManager[int]:
...
@overload
def cactus(_id: str) -> ContextManager[UUID]:
...
@contextmanager
def cactus(_id: str | None = None) -> Iterator[UUID] | Iterator[int]:
if not _id:
yield 1
yield UUID(_id)
Expected Behavior
Mypy should find no issue
Actual Behavior
test.py: note: In function "cactus":
test.py:16:2: error: Overloaded function implementation cannot produce return type of signature 1 [misc]
@contextmanager
^
test.py:16:2: error: Overloaded function implementation cannot produce return type of signature 2 [misc]
@contextmanager
^
Found 2 errors in 1 file (checked 1 source file)
Your Environment
- Mypy version used: 1.0.0
- Mypy command-line flags:
- Mypy configuration options from
mypy.ini(and other config files): - Python version used: 3.10.6
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the supplied Python 3.10.6 example with mypy 1.0.0, focusing on the interaction between @overload and @contextmanager. Trace the type-checking path for the overloaded implementation and add a regression test; done means the example produces no errors without regressing related overload checks.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100