Make it possible to use local stubs

[JukkaL]

Currently the stubs are only searched automatically from the directory stubs below the directory containing (the translated) mypy.py. It would be useful to also look for stubs in a directory relative to the program being type checked/run.

For example, consider the following hierarchy:

d/foo.py
d/stubs/mylib.py

Now if d/foo.py does import mylib, it should refer to the mylib.py file in the stubs directory under d. stubs is a magic directory name for stubs.

[ashleyh]

I wonder if it would be better to be able to specify additional stubs dirs as a command line argument or something...

[JukkaL]

You can specify an additional module path (for looking up stubs or any modules) by using the MYPYPATH environment variable. The implicit 'stubs' directory would just be a convenience.

[JukkaL]

As we now have an alternative extension for stubs, this is no longer as urgent: #345

[JukkaL]

The .pyi extension seems to address this issue, so closing this now.

[DionysusG]

Hi,

This might be a stupid question, but I have tried the both methods to use a local stub: putting the pyi file in the same directory as the py file to run and exporting MYPMPATH to a stub directory and put the pyi file there. I named both pyi file the same name as the py file except for the extension. However, both situations does not throw an error when I run a test program with the incorrect typing hint.

Is there some new way to use the new local stub or I was just stupid and misunderstand the instruction?

[gvanrossum]

Can you provide more specific? Show exactly which files are where, what MYPYPATH is set to, and the error you are getting.

…

--Guido (mobile)

[Kamforka]

So as a follow up I also can't seem to sort out the problems with local stub files.

I have the following project structure:

stub-typing/
├── stubtyping/
│   ├── __init__.py
│   ├── main.py
│   └── main.pyi
└── venv/

main.py has the following content:

def add(a, b):
    return a + b


add(1, 2)
add('a', 'b')

and main.pyi has:

def add(a: int, b: int) -> int: ...

When MYPYPATH is unset and I execute mypy stubtyping/ I have a blank output instead of the expected:

main.py:6: error: Argument 1 to "add" has incompatible type "str"; expected "int"
main.py:6: error: Argument 2 to "add" has incompatible type "str"; expected "int"

I also tried to setMYPYPATH to stubtyping/ but I still get the same results.

What am I missing?

[gvanrossum]

Next time please use the Gitter channel (see project README).

The answer is that mypy ignores main.py because it finds main.pyi in the same directory. This is by design. If you want type annotations, put then in main.py and get rid of main.pyi.