Don't fetch all tasks when there's a default build task

Fixes #95507

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

@@ -2515,38 +2515,58 @@ export abstract class AbstractTaskService extends Disposable implements ITaskSer
 			location: ProgressLocation.Window,
 			title: nls.localize('TaskService.fetchingBuildTasks', 'Fetching build tasks...')
 		};
-		let promise = this.getTasksForGroup(TaskGroup.Build).then((tasks) => {
-			if (tasks.length > 0) {
-				let { defaults, users } = this.splitPerGroupType(tasks);
-				if (defaults.length === 1) {
-					this.run(defaults[0]).then(undefined, reason => {
+		let promise = this.getWorkspaceTasks().then(tasks => {
+			const buildTasks: ConfiguringTask[] = [];
+			for (const taskSource of tasks) {
+				for (const task in taskSource[1].configurations?.byIdentifier) {
+					if ((taskSource[1].configurations?.byIdentifier[task].configurationProperties.group === TaskGroup.Build) &&
+						(taskSource[1].configurations?.byIdentifier[task].configurationProperties.groupType === GroupType.default)) {
+						buildTasks.push(taskSource[1].configurations.byIdentifier[task]);
+					}
+				}
+			}
+			if (buildTasks.length === 1) {
+				this.tryResolveTask(buildTasks[0]).then(resolvedTask => {
+					this.run(resolvedTask).then(undefined, reason => {
 						// eat the error, it has already been surfaced to the user and we don't care about it here
 					});
-					return;
-				} else if (defaults.length + users.length > 0) {
-					tasks = defaults.concat(users);
-				}
+				});
+				return;
 			}
-			this.showIgnoredFoldersMessage().then(() => {
-				this.showQuickPick(tasks,
-					nls.localize('TaskService.pickBuildTask', 'Select the build task to run'),
-					{
-						label: nls.localize('TaskService.noBuildTask', 'No build task to run found. Configure Build Task...'),
-						task: null
-					},
-					true).then((entry) => {
-						let task: Task | undefined | null = entry ? entry.task : undefined;
-						if (task === undefined) {
-							return;
-						}
-						if (task === null) {
-							this.runConfigureDefaultBuildTask();
-							return;
-						}
-						this.run(task, { attachProblemMatcher: true }).then(undefined, reason => {
+
+			return this.getTasksForGroup(TaskGroup.Build).then((tasks) => {
+				if (tasks.length > 0) {
+					let { defaults, users } = this.splitPerGroupType(tasks);
+					if (defaults.length === 1) {
+						this.run(defaults[0]).then(undefined, reason => {
 							// eat the error, it has already been surfaced to the user and we don't care about it here
 						});
-					});
+						return;
+					} else if (defaults.length + users.length > 0) {
+						tasks = defaults.concat(users);
+					}
+				}
+				this.showIgnoredFoldersMessage().then(() => {
+					this.showQuickPick(tasks,
+						nls.localize('TaskService.pickBuildTask', 'Select the build task to run'),
+						{
+							label: nls.localize('TaskService.noBuildTask', 'No build task to run found. Configure Build Task...'),
+							task: null
+						},
+						true).then((entry) => {
+							let task: Task | undefined | null = entry ? entry.task : undefined;
+							if (task === undefined) {
+								return;
+							}
+							if (task === null) {
+								this.runConfigureDefaultBuildTask();
+								return;
+							}
+							this.run(task, { attachProblemMatcher: true }).then(undefined, reason => {
+								// eat the error, it has already been surfaced to the user and we don't care about it here
+							});
+						});
+				});
 			});
 		});
 		this.progressService.withProgress(options, () => promise);