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Legal Python circular imports result in loss of type information #4429
Description
Example:
test/__init__.py:
import typing
from . import a
from . import b
if typing.TYPE_CHECKING:
reveal_type(a.foo())test/a.py:
import test
def foo() -> int:
return test.b.xtest/b.py:
import test
import typing
x = 42
def run() -> int:
if typing.TYPE_CHECKING:
reveal_type(test.a.foo())
return test.a.foo()test/__main__.py
import test
print(test.b.run())Python will execute the above code just fine:
$ python3 -m test
42But mypy loses the type information for test.a in the context of b.py
$ mypy test/__init__.py test/a.py test/b.py
test/b.py:7: error: Revealed type is 'Any'
test/__init__.py:7: error: Revealed type is 'builtins.int'What's odd is if I reorder the files to explicitly pass in b.py first, things work -
$ mypy test/b.py test/a.py test/__init__.py
test/__init__.py:7: error: Revealed type is 'builtins.int'
test/b.py:7: error: Revealed type is 'builtins.int'
Activity
Also fix #4429
Fix issues related to indirect imports in import cycles (#4695)
Fix issues related to indirect imports in import cycles (python#4695)