ndmitchell/hlint

"ignore: {}" causes restricted functions and imports to be ignored

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#748 opened on Aug 23, 2019

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 (7 comments) (0 reactions) (0 assignees)Haskell (1,594 stars) (208 forks)batch import
good first issue

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.

Contributor guide

Tech stack
None
Domain
toolingdeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
HLint usageYAML configHaskell basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate how HLint processes ignore directives in its configuration. The issue reports that an empty `ignore: {}` causes subsequent restrictions on functions and modules to be ignored. Look at the source code for config parsing, likely in files like Config.hs or similar. Reproduce the bug by creating a minimal test case. Check existing comments for any hints or solutions. The fix may involve adjusting the order of applying directives or handling the empty ignore case.