make getPath return undefined when there is not just one root, #28526

src/vs/workbench/api/node/extHostWorkspace.ts

@@ -43,7 +43,16 @@ export class ExtHostWorkspace extends ExtHostWorkspaceShape {
 		// this is legacy from the days before having
 		// multi-root and we keep it only alive if there
 		// is just one workspace folder.
-		return this._workspace ? this._workspace.roots[0].fsPath : undefined;
+		if (!this._workspace) {
+			return undefined;
+		}
+		const { roots } = this._workspace;
+		if (roots.length === 1) {
+			return roots[0].fsPath;
+		}
+		// return `undefined` when there no or more than 1
+		// root folder.
+		return undefined;
 	}
 
 	getRelativePath(pathOrUri: string | vscode.Uri): string {

src/vs/workbench/test/electron-browser/api/extHostWorkspace.test.ts

@@ -48,4 +48,21 @@ suite('ExtHostWorkspace', function () {
 		assert.equal(ws.getRelativePath('/Coding/Two/files/out.txt'), 'files/out.txt');
 		assert.equal(ws.getRelativePath('/Coding/Two2/files/out.txt'), '/Coding/Two2/files/out.txt');
 	});
+
+	test('getPath, legacy', function () {
+		let ws = new ExtHostWorkspace(new TestThreadService(), { id: 'foo', name: 'Test', roots: [] });
+		assert.equal(ws.getPath(), undefined);
+
+		ws = new ExtHostWorkspace(new TestThreadService(), null);
+		assert.equal(ws.getPath(), undefined);
+
+		ws = new ExtHostWorkspace(new TestThreadService(), undefined);
+		assert.equal(ws.getPath(), undefined);
+
+		ws = new ExtHostWorkspace(new TestThreadService(), { id: 'foo', name: 'Test', roots: [URI.file('Folder'), URI.file('Another/Folder')] });
+		assert.equal(ws.getPath(), undefined);
+
+		ws = new ExtHostWorkspace(new TestThreadService(), { id: 'foo', name: 'Test', roots: [URI.file('/Folder')] });
+		assert.equal(ws.getPath(), '/Folder');
+	});
 });