HLS hangs when given an invalid hlint annotation

[expipiplus1]

Your environment

Output of haskell-language-server --probe-tools or haskell-language-server-wrapper --probe-tools:

❯ haskell-language-server-wrapper --probe-tools
haskell-language-server version: 1.1.0.0 (GHC: 8.10.4) (PATH: /nix/store/yc9ljhg8fgb8k8zjlgid04qkq3ffzm5s-haskell-language-server-1.1.0.0/bin/haskell-language-server-wrapper)
Tool versions found on the $PATH
cabal:          3.4.0.0
stack:          Not found
ghc:            8.10.4

Which OS do you use:

Which lsp-client do you use: coc.nvim in neovim on nixos

Describe your project (alternative: link to the project): this commit expipiplus1/fourmolu@6091ab4#diff-7db35ce2b13b8bb7dc43a789dc3cf6074abe57a77051f98a5e7090a09bb6b206R42

Contents of hie.yaml:

cradle:
  multi:
    - path: "data"
      config: { cradle: { none: }}
    - path: "region-tests"
      config: { cradle: { none: }}

    - path: "."
      config:
        cradle:
          cabal:
            - path: "src"
              component: "lib:fourmolu"

            - path: "app"
              component: "fourmolu:exe:fourmolu"

            - path: "tests"
              component: "fourmolu:test:tests"

Steps to reproduce

Clone fourmolu at this commit expipiplus1/fourmolu@6091ab4#diff-7db35ce2b13b8bb7dc43a789dc3cf6074abe57a77051f98a5e7090a09bb6b206R42

Expected behaviour

hls should terminate

Actual behaviour

haskell-language-server doesn't terminate, the last message is

/home/j/src/fourmolu/src/Ormolu/Printer/Meat/Declaration/Value.hs:42:16-56: Error while reading hint file, bad classify pragma
("Hlint: inore use camelCase " :: String)

(not the misspelled 'ignore')

It does respond to SIGTERM

Include debug information

Execute in the root of your project the command haskell-language-server --debug . and paste the logs here:

https://gist.github.com/2e49d2524c9faaa638bebaa919943c82

Things work correctly when 'ignore' is spelled correctly.

[ndmitchell]

All the HLint code that I can see happens under a define, and that could should have catch handlers around it which automatically turn exceptions into errors. I think fixing this particular issue in the HLint plugin would be good (probably adding a specific catch there), but even better to catch it in the define too, so plugins that are slightly wrong don't bring down HLS.

[jneira]

General issue about better error handling of plugins: #1231