`__future__` annotations breaks `TypedDict` `__required/optional_keys__`
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 77.2k
- Forks
- 36k
- PR merge metrics
- PR metrics pending
Description
Bug report
from __future__ import annotations appears to break TypedDict required/optional keys ending up in __required_keys__ and __optional_keys__. mypy works as expected though.
Using the example from https://peps.python.org/pep-0655/#usage-in-python-3-11 as the base
$ cat t.py
from __future__ import annotations
from typing_extensions import NotRequired, TypedDict
class Dog(TypedDict):
name: str
owner: NotRequired[str]
print("required", Dog.__required_keys__)
print("optional", Dog.__optional_keys__)
$ python3 t.py
required frozenset({'name', 'owner'})
optional frozenset()
With the __future__ import removed, works as expected:
$ cat t.py
from typing_extensions import NotRequired, TypedDict
class Dog(TypedDict):
name: str
owner: NotRequired[str]
print("required", Dog.__required_keys__)
print("optional", Dog.__optional_keys__)
$ python3 t.py
required frozenset({'name'})
optional frozenset({'owner'})
Note: breaks across different variations of total and Required/NotRequired and typing_extensions vs typing imports, above is just one example.
https://peps.python.org/pep-0655/#how-to-teach-this contains an example with the __future__ annotations import in place with no mention that it would not cause __required_keys__ and __optional_keys__ becoming populated as expected, so I'm assuming this is a bug.
Your environment
-
CPython versions tested on:
- 3.9.7 +
NotRequiredandTypedDictimports fromtyping_extensions - 3.10.7 + above mentioned imports from
typing_extensions - current 3.11.0rc2+ + above mentioned imports from
typing_extensions - current 3.11.0rc2+ above mentioned imports from
typing
- 3.9.7 +
-
Operating system and architecture: Linux x86_64
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 running the t.py reproduction with and without from __future__ import annotations, across the listed Python versions and both typing and typing_extensions. Trace the TypedDict, Required, and NotRequired entry points to determine how postponed annotations affect key classification. Done means __required_keys__ and __optional_keys__ match the declared annotations for the reported variations.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 42/100