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"ignore: {}" causes restricted functions and imports to be ignored #748
Description
In HLint 2.2.2, the following config:
- ignore: {}
- functions:
- {name: putStrLn, within: []}
- modules:
- {name: [Data.List], as: List}causes no warning to be issued on the following module:
module Main where
import Data.List as L
main :: IO ()
main = putStrLn $ L.intercalate " " ["hlint", "is", "awesome"]whereas the appropriate warnings are raised without the ignore: {}. This is counterintuitive to me, because the README says:
These directives are applied in the order they are given, with later hints overriding earlier ones.
Activity
ndmitchell commentedon Aug 23, 2019
The logic is that when you type
functionsyou are providing predicates for the banned function warning. However, you aren't enabling the banned function warning, just configuring it. So separately you ignored it, and haven't put in a corresponding unignore directive, so it remains ignored. Does that at least make sense why it happens that way?langston-barrett commentedon Aug 23, 2019
Yeah, that makes sense. Is there a way to enable them after configuring them?
It seems like in the more normal configuration (not ignoring everything), enabling and configuring go hand in hand. But when using
ignore: {}, these become separate steps. That makes sense of #747 as well, the difference there being that I figured out a workaround for that.langston-barrett commentedon Feb 12, 2025
The workaround for
modulesis to additionally write the following:neilmayhew commentedon Aug 13, 2025
There's a similar workaround for
functions. Using this hints file, the behaviour is as desired:I therefore think this issue can be closed.
langston-barrett commentedon Aug 14, 2025
Thank you for the workaround! I still find the behavior to be counter-intuitive. I can't imagine a use-case where someone wants to "define" a restricted function without actually checking that it isn't used. Therefore, I'd prefer that the ticket track a change in this behavior.
neilmayhew commentedon Aug 14, 2025
Yes, it does seem a bit counter-intuitive. However, I see this as more of a documentation issue than a bug in the code. It depends on the user's understanding of what the
functionshint means, and if there was a note in its documentation saying that it won't have any effect ifAvoid restricted functionis ignored, perhaps that would make things less counter-intuitive.The same problem would arise if
Avoid restricted functionwas disabled in the source file, so it's not merely an issue with the configuration file syntax (although in that situation it might be more obvious what's going on).A compromise would be for
hlintto issue a warning iffunctionshints exist andAvoid restricted functionis disabled.zliu41 commentedon Aug 15, 2025
I see no downside to enabling the restricting hints automatically after configuration. This is probably not hard to implement, so marking it a good first issue.