Add testbed reproducing diagnostic pull on a saved unsaved-but-named buffer

testbed/client/src/extension.ts

@@ -24,6 +24,7 @@ export async function activate(context: ExtensionContext) {
 		documentSelector: [
 			{ language: 'bat' },
 			{ language: 'bat', notebook: '*' },
+			{ language: 'testbed' },
 			{ scheme: 'file', pattern: '**/.vscode/test.txt' }
 		],
 		synchronize: {
@@ -53,7 +54,8 @@ export async function activate(context: ExtensionContext) {
 			onFocus: true,
 			match: (selector, resource) => {
 				const fsPath = resource.fsPath;
-				return path.extname(fsPath) === '.bat';
+				const ext = path.extname(fsPath);
+				return ext === '.bat' || ext === '.testbed';
 			}
 		},
 		textSynchronization: {

testbed/package.json

@@ -13,6 +13,17 @@
 	"enabledApiProposals": [
 	],
 	"contributes": {
+		"languages": [
+			{
+				"id": "testbed",
+				"aliases": [
+					"Testbed"
+				],
+				"extensions": [
+					".testbed"
+				]
+			}
+		],
 		"commands": [
 			{
 				"command": "testbed.openFile",

testbed/server/src/server.ts

@@ -18,7 +18,7 @@ import {
 	SemanticTokensClientCapabilities, SemanticTokensLegend, SemanticTokensBuilder, SemanticTokensRegistrationType,
 	SemanticTokensRegistrationOptions, ProtocolNotificationType, ChangeAnnotation, WorkspaceChange, CompletionItemKind, DiagnosticSeverity,
 	DocumentDiagnosticReportKind, WorkspaceDiagnosticReport, NotebookDocuments, CompletionList, DidChangeConfigurationNotification,
-	NotificationType
+	NotificationType, ErrorCodes
 } from 'vscode-languageserver/node';
 
 import {
@@ -229,10 +229,18 @@ documents.onDidChangeContent((_event) => {
 	// void connection.sendDiagnostics({ uri: document.uri, diagnostics: validate(document) });
 });
 
+documents.onDidOpen((event) => {
+	connection.console.info(`Document opened: ${event.document.uri} ${event.document.version}`);
+});
+
 documents.onDidSave((event) => {
 	connection.console.info(`Document got saved: ${event.document.uri} ${event.document.version}`);
 });
 
+documents.onDidClose((event) => {
+	connection.console.info(`Document closed: ${event.document.uri}`);
+});
+
 connection.onDidChangeWatchedFiles((params) => {
 	connection.console.log('File change event received');
 	// documents.all().forEach(document => {
@@ -335,6 +343,18 @@ let versionCounter: number = 1;
 connection.languages.diagnostics.on(async (param) => {
 	const uri = URI.parse(param.textDocument.uri);
 	const document = documents.get(param.textDocument.uri);
+	connection.console.info(`Diagnostic pull request for ${param.textDocument.uri} (open: ${document !== undefined})`);
+	// Reproduces microsoft/vscode-languageserver-node#1797 / #1771: after saving an
+	// "unsaved but named" buffer, the client closes the `untitled:` document and then
+	// still issues a `textDocument/diagnostic` request for that same, now closed,
+	// `untitled:` document. A real language server (e.g. tsserver) has no project for
+	// such a URI anymore and fails the request. We mimic that behavior here so the
+	// problematic flow surfaces as an error instead of being silently swallowed.
+	if (document === undefined && uri.scheme !== 'file') {
+		const message = `no project found for URI ${param.textDocument.uri}`;
+		connection.console.error(`error handling method 'textDocument/diagnostic': ${message}`);
+		throw new ResponseError(ErrorCodes.InvalidParams, message);
+	}
 	const content = document !== undefined
 		? document.getText()
 		: uri.scheme === 'file'

testbed/workspace/repro-1797.md

@@ -0,0 +1,51 @@
+# Repro: Diagnostics requested after saving an unsaved-but-named buffer
+
+Reproduces [microsoft/vscode-languageserver-node#1797](https://github.com/microsoft/vscode-languageserver-node/issues/1797)
+(a manifestation of [#1771](https://github.com/microsoft/vscode-languageserver-node/issues/1771)).
+
+## What the testbed sets up
+
+* The client registers a fake programming language `testbed` (files ending in
+  `.testbed`) in `../package.json` and adds it to both the `documentSelector` and
+  the `diagnosticPullOptions.match` filter in `../client/src/extension.ts`.
+* The server (`../server/src/server.ts`) registers for the text document
+  notifications (`didOpen`, `didChange`, `didSave`, `didClose`) and the
+  `textDocument/diagnostic` pull request, logging each so the problematic
+  sequence is visible in the `Testbed` output channel.
+* When a diagnostic pull arrives for a document that is **not open** and whose
+  scheme is **not** `file` (i.e. a closed `untitled:` buffer), the server fails
+  the request with `no project found for URI <uri>`, mirroring how a real
+  language server (e.g. tsserver) reacts.
+
+## Steps to reproduce
+
+1. Build the repo and the testbed:
+   ```sh
+   npm install
+   npm run compile:testbed
+   ```
+2. Open this `testbed` folder in VS Code and run the `Launch Client` debug
+   configuration so the extension loads with the `workspace` folder.
+3. In the Extension Development Host, open an **unsaved but named** buffer for the
+   fake language, e.g. from a terminal:
+   ```sh
+   code-insiders ./newFile.testbed   # or: code ./newFile.testbed
+   ```
+   (or create a new file, set its language to `Testbed`, and keep it unsaved).
+4. Type some content, for example:
+   ```
+   const x = new Map();
+   x.
+   ```
+5. Save the file.
+
+## Expected problematic behavior
+
+On save, VS Code sends `didSave` for the `file:` URI, then `didChange` and
+`didClose` for the original `untitled:` URI, and finally a
+`textDocument/diagnostic` request for the now closed `untitled:` document. The
+`Testbed` output channel shows:
+
+```
+error handling method 'textDocument/diagnostic': no project found for URI untitled:/.../newFile.testbed
+```

testbed/workspace/sample.testbed

@@ -0,0 +1,2 @@
+const x = new Map();
+x.