Fix lingering recent custom tasks

Fixes #93931

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

@@ -101,8 +101,9 @@ export class TaskQuickPick extends Disposable {
 		return tasks;
 	}
 
-	private dedupeConfiguredAndRecent(recentTasks: (Task | ConfiguringTask)[], configuredTasks: (Task | ConfiguringTask)[]): (Task | ConfiguringTask)[] {
+	private dedupeConfiguredAndRecent(recentTasks: (Task | ConfiguringTask)[], configuredTasks: (Task | ConfiguringTask)[]): { configuredTasks: (Task | ConfiguringTask)[], recentTasks: (Task | ConfiguringTask)[] } {
 		let dedupedConfiguredTasks: (Task | ConfiguringTask)[] = [];
+		const foundRecentTasks: boolean[] = Array(recentTasks.length).fill(false);
 		for (let j = 0; j < configuredTasks.length; j++) {
 			const workspaceFolder = configuredTasks[j].getWorkspaceFolder()?.uri.toString();
 			const definition = configuredTasks[j].getDefinition()?._key;
@@ -115,22 +116,31 @@ export class TaskQuickPick extends Disposable {
 				dedupedConfiguredTasks.push(configuredTasks[j]);
 			} else {
 				recentTasks[findIndex] = configuredTasks[j];
+				foundRecentTasks[findIndex] = true;
 			}
 		}
 		dedupedConfiguredTasks = dedupedConfiguredTasks.sort((a, b) => this.sorter.compare(a, b));
-		return dedupedConfiguredTasks;
+		const prunedRecentTasks: (Task | ConfiguringTask)[] = [];
+		for (let i = 0; i < recentTasks.length; i++) {
+			if (foundRecentTasks[i] || ConfiguringTask.is(recentTasks[i])) {
+				prunedRecentTasks.push(recentTasks[i]);
+			}
+		}
+		return { configuredTasks: dedupedConfiguredTasks, recentTasks: prunedRecentTasks };
 	}
 
 	public async getTopLevelEntries(defaultEntry?: TaskQuickPickEntry): Promise<{ entries: QuickPickInput<TaskTwoLevelQuickPickEntry>[], isSingleConfigured?: Task | ConfiguringTask }> {
 		if (this.topLevelEntries !== undefined) {
 			return { entries: this.topLevelEntries };
 		}
-		const recentTasks: (Task | ConfiguringTask)[] = (await this.taskService.readRecentTasks()).reverse();
+		let recentTasks: (Task | ConfiguringTask)[] = (await this.taskService.readRecentTasks()).reverse();
 		const configuredTasks: (Task | ConfiguringTask)[] = this.handleFolderTaskResult(await this.taskService.getWorkspaceTasks());
 		const extensionTaskTypes = this.taskService.taskTypes();
 		this.topLevelEntries = [];
 		// Dedupe will update recent tasks if they've changed in tasks.json.
-		let dedupedConfiguredTasks: (Task | ConfiguringTask)[] = this.dedupeConfiguredAndRecent(recentTasks, configuredTasks);
+		const dedupeAndPrune = this.dedupeConfiguredAndRecent(recentTasks, configuredTasks);
+		let dedupedConfiguredTasks: (Task | ConfiguringTask)[] = dedupeAndPrune.configuredTasks;
+		recentTasks = dedupeAndPrune.recentTasks;
 		if (recentTasks.length > 0) {
 			this.createEntriesForGroup(this.topLevelEntries, recentTasks, nls.localize('recentlyUsed', 'recently used'));
 		}