Auto merge of #15863 - davidbarsky:davidbarsky/start-of-monorepo-mode, r=Veykril

feature: Create `UnindexedProject` notification to be sent to the client

(Note that this branch contains commits from https://github.com/rust-lang/rust-analyzer/pull/15830, which I'll rebase atop of as needed.)

Based on the discussion in https://github.com/rust-lang/rust-analyzer/issues/15837, I've added a notification and off-by-default toggle to send that notification from `handle_did_open_text_document`. I'm happy to rename/tweak this as needed.

I've been using this for a little bit, and it does seem to cause a little bit more indexing/work in rust-analyzer, but it's something that I'll profile as needed, I think.

editors/code/package.json

@@ -1473,6 +1473,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.notifications.unindexedProject": {
+                    "markdownDescription": "Whether to send an UnindexedProject notification to the client.",
+                    "default": false,
+                    "type": "boolean"
+                },
                 "rust-analyzer.numThreads": {
                     "markdownDescription": "How many worker threads in the main loop. The default `null` means to pick automatically.",
                     "default": null,

editors/code/src/ctx.ts

@@ -234,6 +234,23 @@ export class Ctx implements RustAnalyzerExtensionApi {
                     this.outputChannel!.show();
                 }),
             );
+            this.pushClientCleanup(
+                this._client.onNotification(ra.unindexedProject, async (params) => {
+                    if (this.config.discoverProjectRunner) {
+                        const command = `${this.config.discoverProjectRunner}.discoverWorkspaceCommand`;
+                        log.info(`running command: ${command}`);
+                        const uris = params.textDocuments.map((doc) =>
+                            vscode.Uri.parse(doc.uri, true),
+                        );
+                        const projects: JsonProject[] = await vscode.commands.executeCommand(
+                            command,
+                            uris,
+                        );
+                        this.setWorkspaces(projects);
+                        await this.notifyRustAnalyzer();
+                    }
+                }),
+            );
         }
         return this._client;
     }

editors/code/src/lsp_ext.ts

@@ -220,3 +220,9 @@ export type RecursiveMemoryLayoutNode = {
 export type RecursiveMemoryLayout = {
     nodes: RecursiveMemoryLayoutNode[];
 };
+
+export const unindexedProject = new lc.NotificationType<UnindexedProjectParams>(
+    "rust-analyzer/unindexedProject",
+);
+
+export type UnindexedProjectParams = { textDocuments: lc.TextDocumentIdentifier[] };