[QUESTION] mypy complaining about missing attributes when importing typer

[j-martin]

First check

• I used the GitHub search to find a similar issue and didn't find it.
• I searched the Typer documentation, with the integrated search.
• I already searched in Google "How to X in Typer" and didn't find any information.
• I already searched in Google "How to X in Click" and didn't find any information.

Description

I am trying to use the type types get parsed in mypy. From my experience with mypy, the packages are either supported "out of the box" or not at all and must be ignored.

It's a different issue than #53

I am not sure if I am doing something wrong or this is a bug.

I am using mypy==0.770 on Python 3.7

Thanks,

Jean-Martin

Additional context

mypy command:

mypy --show-error-codes --strict some_script.py

mypy error (the line number will not match truncate script below)

some_script.py:10: error: Module has no attribute "Typer"  [attr-defined]
some_script.py:13: error: Untyped decorator makes function "main" untyped  [misc]
some_script.py:14: error: Function is missing a return type annotation  [no-untyped-def]
some_script.py:18: error: Module has no attribute "Option"  [attr-defined]
some_script.py:19: error: Module has no attribute "Option"  [attr-defined]
some_script.py:20: error: Module has no attribute "Option"  [attr-defined]
some_script.py:21: error: Module has no attribute "Option"  [attr-defined]
some_script.py:31: error: Module has no attribute "run"  [attr-defined]

mypy config

[mypy]
namespace_packages = true

# The following 3rd party dependencies don't have type hints. We ignore them one by one instead of
# blindly running with --ignore-missing-imports.

[mypy-typer]

[mypy-setuptools]
ignore_missing_imports = True

Truncated code:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import json

import typer
import yaml

app = typer.Typer()


@app.command(
    help="Something."
)
def main(
    option_a: str = typer.Option(...),
    option_b: str = typer.Option(...),
    option_c: str = typer.Option(...),
    option_d: str = typer.Option(...),
) -> None:
    # Non problematic code
    ...


if __name__ == "__main__":
    typer.run(main)

Workaround

#112 (comment)

[mrpgraae]

I am also having this problem. It is my understanding, that since #58 typer should work with mypy out-of-the-box?

[kevincon]

I'm experiencing the same problem. I'm using typer==0.2.1 and mypy==0.780, and when I try to type check some code I've written that uses Typer, I get errors like error: Module has no attribute "Typer" for any symbol I've imported from the typer module.

[kevincon]

I believe this may be the issue: python/mypy#7030

In short, a recent version of mypy introduced a --no-implicit-reexport feature that that has become part of the default checks enabled when using --strict, which I guess everyone reporting this issue (including me) is using: https://mypy.readthedocs.io/en/latest/command_line.html#cmdoption-mypy-no-implicit-reexport

By default, imported values to a module are treated as exported and mypy allows other modules to import them. This flag changes the behavior to not re-export unless the item is imported using from-as or is included in all.

So I think this issue can be resolved if typer is updated to explicitly export the modules it imports in typer/__init__.py. I.e. change all of the imports in that file like:

typer/typer/__init__.py

Line 5 in 338d05f

from click.exceptions import Abort, BadParameter, Exit

to:

from click.exceptions import Abort as Abort, BadParameter as BadParameter, Exit as Exit

[kevincon]

As a temporary workaround, you can add this section to your project's mypy.ini file to make mypy --strict happy:

[mypy-typer.*]
; https://github.com/tiangolo/typer/issues/112
implicit_reexport = True

[j-martin]

I can confirm this fixed typing entirely with typer. Thank you so much!

[mrpgraae]

Can confirm this workaround fixed it for me too. Thanks!

[tiangolo]

Thanks for the discussion here everyone! @victorphoenix3 added support for mypy --strict on #147.

Available in Typer version 0.3.2 🚀 🎉

[j-martin]

Confirming it solved the mypy issue.

Thanks!