Expose diagnostic_level in Biome LSP

[josephine-njooi]

I am using Biome with VSCode, and find it helpful to start with the recommended set of rules. We only care about rules that error and do not care about warning or information rules, and have configured this in our CI by running biome check . --diagnostic-level=error.

In VSCode, I would only like to see the squiggles for errors, and not for warning or information (which I find distracting). This has been a requested feature in the biome-vscode extension, but was closed because the diagnostic level is not in exposed setting in the LSP.

This is thus a feature request to expose diagnostic_level in the LSP, so that editors can customize rule severity.

An alternate solution to my use case would be to expose a way to configure the recommended ruleset by severity, e.g. a single setting to turn off all rules that are warning and below.

[ematipico]

This is already possible: https://biomejs.dev/reference/vscode/#biomeinlineconfig

[josephine-njooi]

Inline config enables turning off the recommended setting entirely, but it doesn't enable showing only the error rules from the recommended, and ignoring all recommended rules that are warning or information.

In order to achieve this with the inline config, one would have to specify every single warning/information rule in the recommended set, and keep that up to date as the recommended set changes, which is not realistic.

[ematipico]

Ah ok. You'd want a diagnostic level setting, but for LSP.

It should be very easy to implement