Imports protected by TYPE_CHECKING are treated as mandatory

[chrisburr]

Describe the bug

Code which is protected by TYPE_CHECKING is listed as a required import. I'm not sure if to class this as a bug or a feature request but this template fits better.

For example:

from typing import TYPE_CHECKING
import foo
if TYPE_CHECKING:
    import bar

To Reproduce

bash-5.2$ echo $'from typing import TYPE_CHECKING\nimport foo\nif TYPE_CHECKING:\n    import bar' | fawltydeps --list-imports --code - --detailed
<stdin>:2: foo
<stdin>:4: bar

Expected behavior

Import protected by TYPE_CHECKING can be ignored.

Environment

• Version of the code: 0.13.2

Additional context

[jherland]

Thanks for reporting! Agree that TYPE_CHECKING imports should be disregarded by FawltyDeps. Although they are needed by Mypy (or other type checkers) these tools are perfectly capable of reporting the missing dependency themselves.

We're not sure when we'll get to this, so if you want to take a stab at a PR in the meantime we'll be happy to look at it.

Edit: We don't see this as an urgent issue, as the workaround here is straightforward: Add bar (the modules conditionally imported under TYPE_CHECKING) to the set of undeclared dependencies to be ignored, i.e. compare:

echo $'from typing import TYPE_CHECKING\nimport foo\nif TYPE_CHECKING:\n    import bar' \
  | fawltydeps --check-undeclared --code - --detailed

to

echo $'from typing import TYPE_CHECKING\nimport foo\nif TYPE_CHECKING:\n    import bar' \
  | fawltydeps --check-undeclared --code - --detailed --ignore-undeclared bar