Ignoring False positives

[NorfairKing]

It would be really nice to be able to run weeder in CI.
Unfortunately it still shows many false positives, such as the Paths_ modules and TH-spliced functions.
So I propose to have a part of the config file called expected-weeds that lets you describe false positives that weeder should ignore.
It should also error when one of the expected weeds is not found, because otherwise weeds will grow in that section of the configuration file.

[ocharles]

I think you might be asking for a combination of #58, and a way to say that some rules must match - is that correct?

[NorfairKing]

@ocharles yes that sounds right.

[ocharles]

Ok. I think that for TH you probably want those definitions as roots, not ignored weeds. For Paths_ that is outside your control (it's generated code), so ignoring those would be more correct. Currently we have:

roots = [
  # All `main :: IO()` functions
  '^Main.main',

  # Automatically generated and outside our control
  '^Paths_.*',
]

In our config, which you might want to copy.

[NorfairKing]

Ok. I think that for TH you probably want those definitions as roots, not ignored weeds.

Alright, but then I still have a need for unused root patterns to be an error.

[ocharles]

Yea, for sure - I've also wanted weeder to be self weeding there! Maybe a nice little fix for ZuriHac 2024 🙂