Introduce A006 for lambda shadowing

[cielavenir]

I added this to run_tests.py:

def test_lambda_argument_message():
    source = 'takefirst = lambda list: list[0]'
    check_code(source, 'A002')

Then I see this:

>       assert len(return_statements) == len(expected_codes)
E       AssertionError: assert 0 == 1
E        +  where 0 = len([])
E        +  and   1 = len(['A002'])

This MR tries to fix it.

Reproduced in main/Python3, 1.5/Python3 and 1.5/Python2.

/cc @felixvd @ntohge

[gforcada]

Thanks, for taking the time to write the PR! 🙇🏾 😄

Though, I'm not sure if lambda's are really a use case for flake8-builtins 🤔

I mean, if you do:

my_list = list()
my_list.append(1)
my_list.append(2)
my_list.append(3)

list = [1,2,3]

another_list = list()

This last line breaks due to having reassigned the builtin list to an actual list.

But if we do the same with a lambda:

one_list = list()
one_list.append(1)
one_list.append(2)
one_list.append(3)

my_lambda = lambda list: list[0]

my_lambda(one_list) # returns 1

second_list = list()
second_list.append(4)
second_list.append(5)
second_list.append(6)

my_lambda(second_list) # returns 4

This still works... let me think a bit more about it before deciding 🤔

[felixvd]

my_lambda = lambda list: list[0]

I agree this isn't the same level of risk as other A002 errors , but it doesn't exactly look like great practice either.

[gforcada]

Indeed, but then, maybe we could use a new error code A005 for it? 🤔 It means a bit more work though 😕

[cielavenir]

@gforcada done

(sorry that check_function_definition and check_lambda_definition have duplicated code)

[felixvd]

@cielavenir Let's update the Readme too:

A005:
  A lambda argument is shadowing a Python builtin.

[cielavenir]

@felixvd done.

[gforcada]

🙈 sorry! I just merged another contribution that added a A005, we should turn this into a A006. Would you mind updating the code? I can try myself to do it otherwise, though, I'm a bit busy as of late 😕

[cielavenir]

@gforcada merged main

[gforcada]

@cielavenir one last request, sorry! 🙏🏾 could you add a line on CHANGES.rst as well? 🍀

With this it will be ready to get merged 😊

[cielavenir]

@gforcada done

[gforcada]

Thanks!! 😄

The date change was not needed, I will revert it myself after the merge.

[gforcada]

... and flake8-builtins==2.4.0 is released! 🎉