Global tasks don't need a workspace root

Fixes #63951

src/vs/workbench/api/electron-browser/mainThreadTask.ts

@@ -253,7 +253,7 @@ namespace TaskSourceDTO {
 	export function to(value: TaskSourceDTO, workspace: IWorkspaceContextService): ExtensionTaskSource {
 		let scope: TaskScope;
 		let workspaceFolder: IWorkspaceFolder;
-		if (value.scope === void 0) {
+		if ((value.scope === void 0) || ((typeof value.scope === 'number') && (value.scope !== TaskScope.Global))) {
 			if (workspace.getWorkspace().folders.length === 0) {
 				scope = TaskScope.Global;
 				workspaceFolder = undefined;

src/vs/workbench/parts/tasks/electron-browser/terminalTaskSystem.ts

@@ -32,7 +32,7 @@ import { IOutputService, IOutputChannel } from 'vs/workbench/parts/output/common
 import { StartStopProblemCollector, WatchingProblemCollector, ProblemCollectorEventKind } from 'vs/workbench/parts/tasks/common/problemCollectors';
 import {
 	Task, CustomTask, ContributedTask, RevealKind, CommandOptions, ShellConfiguration, RuntimeType, PanelKind,
-	TaskEvent, TaskEventKind, ShellQuotingOptions, ShellQuoting, CommandString, CommandConfiguration, RerunBehavior
+	TaskEvent, TaskEventKind, ShellQuotingOptions, ShellQuoting, CommandString, CommandConfiguration, RerunBehavior, ExtensionTaskSource, TaskScope
 } from 'vs/workbench/parts/tasks/common/tasks';
 import {
 	ITaskSystem, ITaskSummary, ITaskExecuteResult, TaskExecuteKind, TaskError, TaskErrors, ITaskResolver,
@@ -970,17 +970,21 @@ export class TerminalTaskSystem implements ITaskSystem {
 
 	private collectTaskVariables(variables: Set<string>, task: CustomTask | ContributedTask): void {
 		if (task.command) {
-			this.collectCommandVariables(variables, task.command);
+			this.collectCommandVariables(variables, task.command, task);
 		}
 		this.collectMatcherVariables(variables, task.problemMatchers);
 	}
 
-	private collectCommandVariables(variables: Set<string>, command: CommandConfiguration): void {
+	private collectCommandVariables(variables: Set<string>, command: CommandConfiguration, task: CustomTask | ContributedTask): void {
 		this.collectVariables(variables, command.name);
 		if (command.args) {
 			command.args.forEach(arg => this.collectVariables(variables, arg));
 		}
-		variables.add('${workspaceFolder}');
+		// Try to get a scope.
+		const scope = (<ExtensionTaskSource>task._source).scope;
+		if (scope !== TaskScope.Global) {
+			variables.add('${workspaceFolder}');
+		}
 		if (command.options) {
 			let options = command.options;
 			if (options.cwd) {