Add option to ignore code in if TYPE_CHECKING

[GoldsteinE]

Is your feature request related to a problem? Please describe

In typed code, this is common pattern:

from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from some_module import some_type

If some_type is defined in stub, it doesn't have to exist in runtime (e. g. wsgiref.types is only available in .pyi files). Pylint issues an error for this code, while it's perfectly valid.
Pylint isn't a type checker, so it should ignore all code in if TYPE_CHECKING:.

Describe the solution you'd like

Add option like to ignore all errors or, probably, only import-related errors in if TYPE_CHECKING: blocks.

[PCManticore]

Thanks, agree we should take more hints for TYPE_CHECKING.

[dpinol]

I'm trying to preprocess the source code commenting our the imports guarded with TYPE_CHECKING, and then removing types with https://github.com/abarker/strip-hints. Otherwise, pylint would complain of the guarded types used in type hints.
unfortunately strip-hints also removes the types of dataclass fields, and hence I'm writing my own preprocessor :-|

[ssbarnea]

That bug allone makes it very inconvenient to keep using pylint on types projects, to a point where I am even considering removing it. Any chance we can have someone a patch to address it?

[Pierre-Sassoulas]

This is a high priority issue but no one is working on it right now, if you're willing to contribute it could go faster 😄

[matusvalo]

Just a note: As a workaround, disable all checks for a block should help.

from typing import TYPE_CHECKING
if TYPE_CHECKING:
    # pylint: disable=all
    from some_module import some_type

[Pierre-Sassoulas]

Thanks for the clever trick @matusvalo ! For readers who also are would be implementer, this workaround would not work for circular imports for example, so we still need this feature very badly :)