Add showSyntaxErrors server setting

[dhruvmanila]

Summary

This PR adds a new showSyntaxErrors server setting for astral-sh/ruff#12059 in ruff-lsp.

Test Plan

VS Code

Requires: astral-sh/ruff-vscode#504

Verified that the VS Code extension is using the bundled ruff-lsp and the debug build of ruff:

2024-06-27 08:47:49.567 [info] Server run command: /Users/dhruv/work/astral/ruff-vscode/.venv/bin/python /Users/dhruv/work/astral/ruff-vscode/bundled/tool/server.py
2024-06-27 08:47:49.820 [info] Using 'path' setting: /Users/dhruv/work/astral/ruff/target/debug/ruff
2024-06-27 08:47:49.827 [info] Inferred version 0.4.10 for: /Users/dhruv/work/astral/ruff/target/debug/ruff
2024-06-27 08:47:49.828 [info] Found ruff 0.4.10 at /Users/dhruv/work/astral/ruff/target/debug/ruff

Using the following VS Code config:

{
  "ruff.nativeServer": false,
  "ruff.path": ["/Users/dhruv/work/astral/ruff/target/debug/ruff"],
  "ruff.showSyntaxErrors": false
}

First, set ruff.showSyntaxErrors to true:

And then set it to false:

Neovim

Using the following Ruff server config:

require('lspconfig').ruff_lsp.setup {
  cmd = { '/Users/dhruv/work/astral/ruff-lsp/.venv/bin/ruff-lsp' },
  init_options = {
    settings = {
      path = { '/Users/dhruv/work/astral/ruff/target/debug/ruff' },
      showSyntaxErrors = true,
    },
  },
}

First, set showSyntaxErrors to true:

And then set it to false:

[dhruvmanila]

This is actually required after v0.5.0.

[MichaReiser]

If you say it is required, does it mean that Ruff-LSP crashes or is it because it otherwise shows syntax errors as warnings?

I guess there's not much we can do about it other than keeping to emit E999 in the JSON emitter for syntax errors. It might be worth to do so for a while.

[dhruvmanila]

No, I meant that the code field in JSON would be either:

1. E999 for all Ruff versions before v0.5
2. None for Ruff version v0.5 and later

Both are included in this list.

[dhruvmanila]

If you say it is required, does it mean that Ruff-LSP crashes or is it because it otherwise shows syntax errors as warnings?

Oh, I think I read your question wrong but yes otherwise it'll emit syntax errors as warnings. This is why I'm including None in this list so that it's emitted as error.

[dhruvmanila]

I guess there's not much we can do about it other than keeping to emit E999 in the JSON emitter for syntax errors. It might be worth to do so for a while.

I'm not sure about that. If we do keep E999 in the JSON emitter, it should probably be the same for other emitters as well otherwise users might find it confusing.

The current change will only break if there are any other diagnostics emitted by Ruff which doesn't have a rule code and is suppose to be a warning instead. I think it'll be a quite some time before this happens and by that time I think ruff-lsp will be deprecated.

[MichaReiser]

Makes sense. Let's ship as is. I expect that most users are using the most recent extension anyway because they auto-update.

[dhruvmanila]

We use settings.get so this change is backwards compatible i.e., the new ruff-lsp version can be used with an old VS Code extension version.