Controlling workspace/diagnostic/refresh

[alanz]

rust-analyzer version: rust-analyzer 0.3.2162-standalone (3b3a87f 2024-10-27)
rustc version: rustc 1.81.0 (eeb90cda1 2024-09-04)
editor or extension: emacs lsp-mode
relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)
repository link (if public, optional): rust-analyzer)

When pull diagnostics were introduced in LSP there was no specific client configuration to enable them, since it is up to the client to pull them.

Pull diagnostics are not currently implemented emacs lsp-mode.
This week's RA release enabled pull diagnostics, together with workspace/diagnostic/refresh, which originates from the server. This server request should be gated by

/**
 * Workspace client capabilities specific to diagnostic pull requests.
 *
 * @since 3.17.0
 */
export interface [DiagnosticWorkspaceClientCapabilities](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#diagnosticWorkspaceClientCapabilities) {
	/**
	 * Whether the client implementation supports a refresh request sent from
	 * the server to the client.
	 *
	 * Note that this event is global and will force the client to refresh all
	 * pulled diagnostics currently shown. It should be used with absolute care
	 * and is useful for situation where a server for example detects a project
	 * wide change that requires such a calculation.
	 */
	refreshSupport?: boolean;
}

but is currently gated on the mere presence of the textDocument.diagnostics client config. (via

rust-analyzer/crates/rust-analyzer/src/main_loop.rs

Line 420 in 3b3a87f

let supports_diagnostic_pull_model = self.config.text_document_diagnostic();

)

So this decision should be made based on workspace.diagnostice.refreshSupport instead.

Related: emacs-lsp/lsp-mode#4570