HLS HLint plugin doesn't preserve HLint's severities

[dariooddenino]

Your environment

Which OS do you use?
Ubuntu 20.04
Which version of GHC do you use and how did you install it?
9.2.8 form ghcup

Which LSP client (editor/plugin) do you use?
helix
Which version of HLS do you use and how did you install it?
2.4.0.0 from ghcup
Have you configured HLS in any way (especially: a hie.yaml file)?
I have a hie.yaml file, but I don't think it's relevant to this issue.

What's wrong?

I have added this line to my .hlint.yaml file:

- error: {name: Avoid restricted module}

When running hlint I correctly get:

src/Domain/EntityEvent.hs:8:1-24: Error: Avoid restricted module
Found:
  import Infrastructure.DB
Note: may break the code

1 error

HLS reports the same issue but with severity: 3, making it render as a suggestion instead of an error in my editor:

{"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"diagnostics":[{"code":"Avoid restricted module","message":"Avoid restricted module\nFound:\n  import Infrastructure.DB ( foo )\nmay break the code\n","range":{"end":{"character":30,"line":7},"start":{"character":0,"line":7}},"severity":3,"source":"hlint"}],"uri":".../src/Domain/EntityEvent.hs","version":1}}

Is this something that's not supported (yet)? Is it possible that it's hlint's fault instead?

Thanks

[michaelpj]

The hlint plugin sets the severity to Information always: https://github.com/haskell/haskell-language-server/blob/master/plugins/hls-hlint-plugin/src/Ide/Plugin/Hlint.hs#L252

No comment, so who knows why. I think it would be pretty reasonable to follow hlint's severities there, should be an easy fix.

[IAmPara0x]

I have created a PR for it: #3902. And I have tested it locally. Hope this solves the issue.

[michaelpj]

Just as a note for anyone coming here in future: we decided on the following behaviour:

• error severities are kept
• all other severities are downgraded

This is because hlint pervasively uses "warning" to mean something much less severe than GHC's warnings, but its "error"s are still pretty bad.