mypy 找不到黑色的类型提示

Question

I have a file test.py which only contains the line import black . When I run mypy test.py , I get the following error:

test.py:1: error: Skipping analyzing 'black': found module but no type hints or library stubs
test.py:1: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)

However, when I look at the source for black , it seems like everything has type hints. What do I need to do differently in mypy to get it to use the type hints when I import black ?

Environment setup:

conda create -n test python=3.7 -y
conda activate test
pip install black mypy

EDIT - From the link mentioned in the error message :

Mypy will not try inferring the types of any 3rd party libraries you have installed unless they either have declared themselves to be PEP 561 compliant stub package or have registered themselves on typeshed

I had assumed black have satisfied one of these requirements, but it does not seem to be registered on typeshed . From here , it seems that a package must have a py.typed file to be PEP 561-compliant with inline annotations, and black doesn't seem to have that either.

My question still stands - given that the typing information is already there in black , how can I (without needing a PR to be approved somewhere) get mypy to use that?

I don't see any details about the py.typed file - if that is just an empty file and only its existence matters, I assume I can create it somewhere and then typing will work?

Answer 1

EDIT - this has been fixed in black now ( PR here , merged 5/8/2020), so in new versions no workaround is necessary.

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Creating an empty file named py.typed in the install directory is sufficient:

cd ~/anaconda/envs/test/lib/python3.7/site-packages # or wherever your packages are installed
# black.py is directly in site-packages, but py.typed needs to be in a directory for the module
mkdir black
touch black/py.typed