LSP: Discard publishDiagnostic from uninitialized servers

[the-mikedavis]

The spec explicitly disallows publishDiagnostic to be sent before the initialize response:

... the server is not allowed to send any requests or notifications to the client until it has responded with an InitializeResult ...

(https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#initialize)

But if a non-compliant server sends this we currently panic because we '.expect()' the server capabilities to be known to fetch the position encoding. Instead of panicking we can discard the notification and log the non-compliant behavior.

See #7466

[pascalkuthe]

Are there any other cases where we expect the capabilities? I think I saw that a few times and that could cause simillar bugs (diagnostics is likely just the most common)

[the-mikedavis]

It looks like this is actually the only place in handle_language_server_message that we assume we have the capabilities. Though it looks like we should be checking the capabilities when applying workspace edits. Currently it's hard-coded:

helix/helix-term/src/application.rs

Lines 1045 to 1049 in d8f9b90

	let res = apply_workspace_edit(
	&mut self.editor,
	helix_lsp::OffsetEncoding::Utf8,
	&params.edit,
	);

I'll make a PR for that too

[pascalkuthe]

oh yeah, that should definitely be fixed. I remember fixing this elsewhere too but I must have missed that. Good catch!

[pascalkuthe]

thanks!