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stubtest: Spurious warning related to symbols in '__all__' #9935
Description
Bug Report
I'm getting an error from stubtest checking a package that lists a submodule in __all__.
To Reproduce
- Create a package with a submodule
$ mkdir pkg
$ touch pkg/__init__.py
$ touch pkg/mod.py- So far,
stubtestseems to be happy with it
$ PYTHONPATH=$PWD stubtest pkg- Now add
modto__all__in__init.pyand runstubtestagain
$ echo "__all__=['mod']" > pkg/__init__.py
$ PYTHONPATH=$PWD stubtest pkg
error: pkg.mod is not present in stub
Stub:
MISSING
Runtime:
MISSINGNote, adding respective *.pyi files do not fix the problem.
- Mypy version used: latest master
- Python version used: 3.9
- Operating system and version: Linux (Fedora 33)
Activity
hauntsaninja commentedon Jan 22, 2021
This example is confusing, since the "stub" stubtest is looking at is actually just the source file. This is a weird way of using stubtest — what are you trying to accomplish?
Moreover, the complaint is kind of true.
Note if you were to add
from . import modto your__init__.py, things would work.Finally, the flag
--ignore-missing-stubwill let you ignore errors caused by things missing from your stubs.dalcinl commentedon Jan 22, 2021
As I mentioned before, adding
*.pyifiles do not fix the problem.Let's try again, using *.pyi stub files alongside the *.py files:
$ mkdir pkg $ touch pkg/__init__.py $ touch pkg/__init__.pyi $ touch pkg/mod.py $ touch pkg/mod.pyi $ PYTHONPATH=$PWD stubtest pkgIMHO, the complaint is not true, this is a perfectly valid Python package. The fact that
modis listed in__all__does not imply that the package's__init__.pyshould import the submodule. To the best of my knowledge, the purpose of__all__is to control howfrom pkg import *behaves, look yourself:so there is no real requirement for
from . import modinpkg/__init__.py.I'm not sure of this behavior of
stubteston handling__all__is a bug or it is intentional, but in any case it is incorrect. Again, listing'something'in__all__does not mean thatsomethinghas to be present in the namespace. That's my understanding from Python's documentation, and it has worked that way at least since the beginnings of this century, when we where using Python 2.2.I'm trying to use
stubtestto setup a sort of "lint" for my manually maintained stubs. The flag--ignore-missing-stubis not an option, it does not operate at the stub file level, it will ignore actual missing stub entries.stubtest: import submodules mentioned in __all__
stubtest: import submodules mentioned in __all__
hauntsaninja commentedon Jan 22, 2021
Okay, gotcha. I think mypy in general doesn't handle this use of
__all__correctly. Leaving stubtest aside for now, something like:Anyway, for now I opened #9943 which should fix the runtime half of stubtest. That is, after that PR you would be able to get things working by adding
from . import modto your stub.cc @srittau since you were resurrecting the stub PEP and you might have opinions about how
__all__in stubs should worksrittau commentedon Jan 23, 2021
We decided that it's probably best if
__all__in stubs works exactly like it does in implementations. It must be a list literal of string and customizes export behavior.stubtest: import submodules mentioned in __all__ (#9943)