python / python/mypy

'Cannot determine type of "<symbol>"' when circular dependencies

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bug topic-import-cycles
Dominant language
Python
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Description

Is this even an error that you care about or throw intentionally?

my-app/
├─ main.py
├─ a.py
├─ b.py

main.py:

from b import B
from a import b

main = B()

a.py:

from b import b as b
from main import main

reveal_type(main)

b.py:

b = 1

class B:
    ...
> mypy main.py
a.py:4: error: Cannot determine type of "main"

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Research direction

Reproduce the report with the shown main.py, a.py, and b.py files by running mypy main.py. Trace how the circular imports and reveal_type(main) are analyzed, then determine whether the diagnostic is intentional; done should establish and test the intended behavior for this example.

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
Needs clarification
Newbie friendliness
35/100

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