Does not recognize additional --builtins

[kthy]

As per the docs, it is possible to add builtins to flake8 by passing the --builtins flag or through config files.

However, these are not recognized by flake8-builtins:

import gettext

gettext.install("minimal_repro")


def id(s):
    return s


def _(s):
    return s


print(id("foo"))
print(_("bar"))

$ python ./no_custom_builtins.py
foo
bar
$ flake8 ./no_custom_builtins.py --builtins=_
./no_custom_builtins.py:1:1: D100 Missing docstring in public module
./no_custom_builtins.py:6:1: A001 variable "id" is shadowing a python builtin
./no_custom_builtins.py:6:1: D103 Missing docstring in public function

A001 should be reported for both functions.

[gforcada]

@kthy thanks for the report and for using flake8-builtins! ✨ I'm sorry to answer so late, my real life is rather busy as of late 😅

I'm not sure if we are mixing things here 🤔

flake8-builtins looks for what's on the python standard library and reports re-definitions of them, so on your example def id gets a warning about it. def _ though does not, as the python standard library does not have a underscore function.

This configuration option from flake8 that you point to the documentation, if I read it correctly, I understand it as that if you pass --builtins=my_custom_function to flake8 and then have the following code:

import random

random.choice(my_custom_function())

flake8 would not complain that you did not import my_custom_function as is a forced builtin.

In your example, as you are doing def _() and the underscore function is not a builtin you don't get a warning from flake8-builtins nor from flake8 itself as you define it. If you remove the def _ and re-run flake8 you will see a warning from flake8 itself. If then you add --builtins=_ when invoking flake8 that warning should go away.

Let me know if I got it wrong!

On the other hand though, we could add support in flake8-builtins to also warn if one overrides builtins provided via --builtins flake8 parameter/configuration. Would that be something you wish to have in flake8-builtins?

[kthy]

My example does an explicit definition of _ but that was just for repro purposes. The real use case is that the gettext module of the stdlib modifies the builtins on the fly, adding a _() function for translations.

we could add support in flake8-builtins to also warn if one overrides builtins provided via --builtins flake8 parameter/configuration. Would that be something you wish to have in flake8-builtins?

That's exactly what I was looking for, yes! 😁

[gforcada]

@kthy support for your specific request hasn't been implemented so far, but maybe #86 is a good enough solution for you?

Feel free to re-open if you disagree 😄

[kthy]

I may be misunderstanding #86, but doesn't it do exactly the opposite of what I want here?

[gforcada]

Oh my, totally right 😅