fix #31553

src/vs/vscode.d.ts

@@ -4739,12 +4739,15 @@ declare module 'vscode' {
 		 * Returns a path that is relative to the workspace folder or folders.
 		 *
 		 * When there are no [workspace folders](#workspace.workspaceFolders) or when the path
-		 * is not a child of them, the input is returned.
+		 * is not contained in them, the input is returned.
 		 *
 		 * @param pathOrUri A path or uri. When a uri is given its [fsPath](#Uri.fsPath) is used.
+		 * @param includeWorkspaceFolder When `true` and when the given path is contained inside a
+		 * workspace folder the name of the workspace is prepended. Defaults to `true` when there are
+		 * multiple workspace folders and `false` otherwise.
 		 * @return A path relative to the root or the input.
 		 */
-		export function asRelativePath(pathOrUri: string | Uri): string;
+		export function asRelativePath(pathOrUri: string | Uri, includeWorkspaceFolder?: boolean): string;
 
 		/**
 		 * Creates a file system watcher.

src/vs/workbench/api/node/extHost.api.impl.ts

@@ -386,8 +386,8 @@ export function createApiFactory(
 				apiUsage.publicLog('workspace#onDidChangeWorkspaceFolders');
 				return extHostWorkspace.onDidChangeWorkspace(listener, thisArgs, disposables);
 			},
-			asRelativePath: (pathOrUri) => {
-				return extHostWorkspace.getRelativePath(pathOrUri);
+			asRelativePath: (pathOrUri, includeWorkspace) => {
+				return extHostWorkspace.getRelativePath(pathOrUri, includeWorkspace);
 			},
 			findFiles: (include, exclude, maxResults?, token?) => {
 				return extHostWorkspace.findFiles(include, exclude, maxResults, token);

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

@@ -117,7 +117,7 @@ export class ExtHostWorkspace extends ExtHostWorkspaceShape {
 		return roots[0].fsPath;
 	}
 
-	getRelativePath(pathOrUri: string | vscode.Uri): string {
+	getRelativePath(pathOrUri: string | vscode.Uri, includeWorkspace?: boolean): string {
 
 		let path: string;
 		if (typeof pathOrUri === 'string') {
@@ -139,8 +139,12 @@ export class ExtHostWorkspace extends ExtHostWorkspaceShape {
 			return normalize(path);
 		}
 
+		if (typeof includeWorkspace === 'undefined') {
+			includeWorkspace = this.workspace.roots.length > 1;
+		}
+
 		let result = relative(folder.uri.fsPath, path);
-		if (this.workspace.roots.length > 1) {
+		if (includeWorkspace) {
 			result = `${folder.name}/${result}`;
 		}
 		return normalize(result);

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

@@ -49,6 +49,28 @@ suite('ExtHostWorkspace', function () {
 		assert.equal(ws.getRelativePath('/Coding/Two2/files/out.txt'), '/Coding/Two2/files/out.txt');
 	});
 
+	test('slightly inconsistent behaviour of asRelativePath and getWorkspaceFolder, #31553', function () {
+		const mrws = new ExtHostWorkspace(new TestThreadService(), { id: 'foo', roots: [URI.file('/Coding/One'), URI.file('/Coding/Two')], name: 'Test' });
+
+		assert.equal(mrws.getRelativePath('/Coding/One/file.txt'), 'One/file.txt');
+		assert.equal(mrws.getRelativePath('/Coding/One/file.txt', true), 'One/file.txt');
+		assert.equal(mrws.getRelativePath('/Coding/One/file.txt', false), 'file.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two/files/out.txt'), 'Two/files/out.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two/files/out.txt', true), 'Two/files/out.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two/files/out.txt', false), 'files/out.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two2/files/out.txt'), '/Coding/Two2/files/out.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two2/files/out.txt', true), '/Coding/Two2/files/out.txt');
+		assert.equal(mrws.getRelativePath('/Coding/Two2/files/out.txt', false), '/Coding/Two2/files/out.txt');
+
+		const srws = new ExtHostWorkspace(new TestThreadService(), { id: 'foo', roots: [URI.file('/Coding/One')], name: 'Test' });
+		assert.equal(srws.getRelativePath('/Coding/One/file.txt'), 'file.txt');
+		assert.equal(srws.getRelativePath('/Coding/One/file.txt', false), 'file.txt');
+		assert.equal(srws.getRelativePath('/Coding/One/file.txt', true), 'One/file.txt');
+		assert.equal(srws.getRelativePath('/Coding/Two2/files/out.txt'), '/Coding/Two2/files/out.txt');
+		assert.equal(srws.getRelativePath('/Coding/Two2/files/out.txt', true), '/Coding/Two2/files/out.txt');
+		assert.equal(srws.getRelativePath('/Coding/Two2/files/out.txt', false), '/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);