no error when setting `init=False` on `Final` field in dataclass
Open
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feature
good-second-issue
priority-2-low
topic-dataclasses
topic-final
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
from typing import Final
from dataclasses import dataclass, field
@dataclass
class Foo:
a: Final[int] = field(init=False) # no error
Foo().a # runtime error
related: #13118
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.
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- Open a pull request that references the issue number.
Research direction
Start with the provided dataclass reproduction in the issue and compare its behavior with related issue #13118. Trace how mypy handles Final fields and dataclass() field options, then verify that the invalid combination produces an error rather than allowing the shown runtime failure.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 38/100