Support taskVar variables from problem matcher named capture groups

Fixes #303361

Introduces \\\ variables that extract named capture groups
from a task problem matcher's endsPattern and make them available for
substitution in launch configurations and other variable-resolved contexts.

Changes:
- WatchingProblemCollector.tryFinish() extracts matches.groups from endsPattern
- IProblemCollectorEvent carries capturedVariables in BackgroundProcessingEnds
- TerminalTaskSystem registers captured variables via contributeVariable()
- VariableKind.TaskVar added to the enum
- Test added for taskVar variable resolution
- .vscode/launch.json updated to use \

.vscode/launch.json

@@ -660,7 +660,7 @@
 			"name": "Component Explorer (Edge)",
 			"type": "msedge",
 			"request": "launch",
-			"url": "http://localhost:5337/___explorer",
+			"url": "${taskVar:componentExplorerUrl}",
 			"preLaunchTask": "Launch Component Explorer",
 			"presentation": {
 				"group": "1_component_explorer",
@@ -671,7 +671,7 @@
 			"name": "Component Explorer (Chrome)",
 			"type": "chrome",
 			"request": "launch",
-			"url": "http://localhost:5337/___explorer",
+			"url": "${taskVar:componentExplorerUrl}",
 			"preLaunchTask": "Launch Component Explorer",
 			"presentation": {
 				"group": "1_component_explorer",

.vscode/tasks.json

@@ -410,7 +410,7 @@
 				"background": {
 					"activeOnStart": true,
 					"beginsPattern": ".*Setting up sessions.*",
-					"endsPattern": "Redirection server listening on.*"
+					"endsPattern": "  current: (?<componentExplorerUrl>.*) \\(current\\)"
 				}
 			}
 		},

src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts

@@ -177,6 +177,7 @@ export class TerminalTaskSystem extends Disposable implements ITaskSystem {
 	private _terminalTabActions = [{ id: RerunForActiveTerminalCommandId, label: nls.localize('rerunTask', 'Rerun Task'), icon: rerunTaskIcon }];
 	private _taskTerminalActive: IContextKey<boolean>;
 	private readonly _taskStartTimes = new Map<number, number>();
+	private readonly _capturedTaskVariables = new Map<string, string>();
 
 	taskShellIntegrationStartSequence(cwd: string | URI | undefined): string {
 		return (
@@ -898,6 +899,9 @@ export class TerminalTaskSystem extends Disposable implements ITaskSystem {
 					if (this._busyTasks[mapKey]) {
 						delete this._busyTasks[mapKey];
 					}
+					if (event.capturedVariables) {
+						this._registerCapturedVariables(event.capturedVariables);
+					}
 					this._fireTaskEvent(TaskEvent.inactive(task, terminal?.instanceId, this._takeTaskDuration(terminal?.instanceId)));
 					if (eventCounter === 0) {
 						if ((watchingProblemMatcher.numberOfMatches > 0) && watchingProblemMatcher.maxMarkerSeverity &&
@@ -1170,6 +1174,15 @@ export class TerminalTaskSystem extends Disposable implements ITaskSystem {
 		return Date.now() - startTime;
 	}
 
+	private _registerCapturedVariables(capturedVariables: ReadonlyMap<string, string>): void {
+		for (const [name, value] of capturedVariables) {
+			this._capturedTaskVariables.set(name, value);
+			if (!this._configurationResolverService.resolvableVariables.has(`taskVar:${name}`)) {
+				this._configurationResolverService.contributeVariable(`taskVar:${name}`, async () => this._capturedTaskVariables.get(name));
+			}
+		}
+	}
+
 	private _createTerminalName(task: CustomTask | ContributedTask): string {
 		const needsFolderQualification = this._contextService.getWorkbenchState() === WorkbenchState.WORKSPACE;
 		return needsFolderQualification ? task.getQualifiedLabel() : (task.configurationProperties.name || '');

src/vs/workbench/contrib/tasks/common/problemCollectors.ts

@@ -24,11 +24,12 @@ export const enum ProblemCollectorEventKind {
 
 export interface IProblemCollectorEvent {
 	kind: ProblemCollectorEventKind;
+	capturedVariables?: ReadonlyMap<string, string>;
 }
 
 namespace IProblemCollectorEvent {
-	export function create(kind: ProblemCollectorEventKind) {
-		return Object.freeze({ kind });
+	export function create(kind: ProblemCollectorEventKind, capturedVariables?: ReadonlyMap<string, string>) {
+		return Object.freeze({ kind, capturedVariables });
 	}
 }
 
@@ -563,7 +564,8 @@ export class WatchingProblemCollector extends AbstractProblemCollector implement
 				}
 				if (this._activeBackgroundMatchers.delete(background.key)) {
 					this.resetCurrentResource();
-					this._onDidStateChange.fire(IProblemCollectorEvent.create(ProblemCollectorEventKind.BackgroundProcessingEnds));
+					const capturedVariables = matches.groups ? new Map(Object.entries(matches.groups)) : undefined;
+					this._onDidStateChange.fire(IProblemCollectorEvent.create(ProblemCollectorEventKind.BackgroundProcessingEnds, capturedVariables));
 					result = true;
 					this.lines.push(line);
 					const owner = background.matcher.owner;

src/vs/workbench/services/configurationResolver/common/configurationResolver.ts

@@ -82,6 +82,7 @@ export enum VariableKind {
 	Command = 'command',
 	Input = 'input',
 	ExtensionInstallFolder = 'extensionInstallFolder',
+	TaskVar = 'taskVar',
 
 	WorkspaceFolder = 'workspaceFolder',
 	Cwd = 'cwd',

src/vs/workbench/services/configurationResolver/test/electron-browser/configurationResolverService.test.ts

@@ -706,6 +706,20 @@ suite('Configuration Resolver Service', () => {
 		});
 	});
 
+	test('contributed taskVar variable', () => {
+		const url = 'http://localhost:5678';
+		const variable = 'taskVar:componentExplorerUrl';
+		const configuration = {
+			'url': '${taskVar:componentExplorerUrl}/___explorer',
+		};
+		configurationResolverService!.contributeVariable(variable, async () => { return url; });
+		return configurationResolverService!.resolveWithInteractionReplace(workspace, configuration).then(result => {
+			assert.deepStrictEqual({ ...result }, {
+				'url': `${url}/___explorer`
+			});
+		});
+	});
+
 	test('resolveWithEnvironment', async () => {
 		const env = {
 			'VAR_1': 'VAL_1',