Mypy: unable to supress 'already defined on line' errors in idiomatic behave

[mikedlr]

Please provide more information to help us understand the issue:

The standard idiom for behave steps is to reuse the step_impl() function name for each step definition. Since step functions are looked up through a separate function this makes sense.

With mypy it seems impossible to supress the messages that occur

features/steps/add.py:11: error: Name 'step_impl' already defined on line 6
features/steps/add.py:16: error: Name 'step_impl' already defined on line 6
features/steps/add.py:21: error: Name 'step_impl' already defined on line 6

This means that code which is otherwise correct fails.

The actual behavior can be seen with the following commands

• git clone -b pass_mypy [email protected]:mikedlr/behave_minimal_example.git
• cd behave_minimal_example/
• mypy features/steps/add.py

which outputs:

features/steps/add.py:11: error: Name 'step_impl' already defined on line 6
features/steps/add.py:16: error: Name 'step_impl' already defined on line 6
features/steps/add.py:21: error: Name 'step_impl' already defined on line 6

the expected behavior would be to show no errors.

$ python --version
Python 3.6.7
$ mypy --version
mypy 0.660

[essamzaroura]

step_impl is Work in Pycharm why in VScode isn't work ?
what we need to do ?

[gvanrossum]

I don't think something as esoteric as this library will be supported in the near future. Don't other linters complain? You can probably write a mypy plugin to change this if you really wanted (head over to Gitter for help).

[kenpower]

I don't think something as esoteric as this library will be supported in the near future. Don't other linters complain? You can probably write a mypy plugin to change this if you really wanted (head over to Gitter for help).

"something as esoteric as this library" - do you mean mypy or behave?

[gvanrossum]

I presume I meant behave (which to this day I have never heard of outside this ticket).

[hauntsaninja]

I ran into this recently with functools.singledispatch, which often uses multiple functions with the name _.
A better solution that exists now is using mypy's error codes ([no-redef])