F401 is emitted even when "locals" is used in the same scope as not explicitly used imports

[asottile]

In GitLab by @fbessou on Oct 7, 2019, 02:47

Please describe how you installed Flake8

pip install flake8  # in a virtualenv

Please provide the exact, unmodified output of flake8 --bug-report

{
  "dependencies": [
    {
      "dependency": "entrypoints",
      "version": "0.3"
    }
  ],
  "platform": {
    "python_implementation": "CPython",
    "python_version": "3.7.3",
    "system": "Linux"
  },
  "plugins": [
    {
      "is_local": false,
      "plugin": "mccabe",
      "version": "0.6.1"
    },
    {
      "is_local": false,
      "plugin": "pycodestyle",
      "version": "2.5.0"
    },
    {
      "is_local": false,
      "plugin": "pyflakes",
      "version": "2.1.1"
    }
  ],
  "version": "3.7.8"
}

Please describe the problem or feature

Flake8 emits F401 errors for imports which are not explictly used but accessed through calls to locals().
This is not the case for variables: F841 is not emitted when a variable is in the same scope as a locals() call.
I would expect a call to locals() to remove the F401 error.

Here is what I would like to achieve:

def modules():
    import m1  # F401
    import m2  # F401
    import m3  # F401
    import m4  # F401
    import m5  # F401
    return locals()

def register():
    for module in modules():
       module.register()

def unregister():
    for module in reversed(modules()):
        module.unregister()

Examples

def modules():
    import a
    import b
    return locals()

emits

__init__.py:2:5: F401 'a' imported but unused
__init__.py:3:5: F401 'b' imported but unused

No error is emitted for variables which are only accessed through locals:

def values():
    a = 1
    b = 2
    return locals()

[asottile]

In GitLab by @fbessou on Oct 7, 2019, 02:48

changed the description

[asottile]

In GitLab by @fbessou on Oct 7, 2019, 02:48

changed the description

[asottile]

In GitLab by @asottile on Oct 7, 2019, 06:02

flake8 is just a wrapper around other tools and does not implement any checks of its own -- the F checks are implemented by pyflakes

that said, using locals() is almost always a bad idea, all static analysis is kinda shot at that point

[asottile]

In GitLab by @asottile on Oct 7, 2019, 06:02

closed