python / python/mypy

Understand how _ignore_ attribute affects Enum subclasses

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feature topic-enum
Dominant language
Python
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Description

Feature
In code like this, mypy should raise the indicated error:

class Some(Enum):
   a = 1
   b = 2
   _ignore_ = ('a',)

reveal_type(Some.a) # E: "Type[Some]" has no attribute "a"

mypy should understand the effect that _ignore_ has in Enum subclasses.

This issue is a follow-on to PR #12128.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing PR #12128 and mypy's existing Enum handling and tests. Add regression coverage for the shown ignore case, with the work complete when mypy reports that Some.a is not an attribute of Some as indicated.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
devtools
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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