Finalize task custom execution variable resolving

Fixes #81007

src/vs/vscode.d.ts

@@ -6123,9 +6123,10 @@ declare module 'vscode' {
 		 * [Pseudoterminal.close](#Pseudoterminal.close). When the task is complete fire
 		 * [Pseudoterminal.onDidClose](#Pseudoterminal.onDidClose).
 		 * @param process The [Pseudoterminal](#Pseudoterminal) to be used by the task to display output.
-		 * @param callback The callback that will be called when the task is started by a user.
+		 * @param callback The callback that will be called when the task is started by a user. Any ${} style variables that
+		 * were in the task definition will be resolved and passed into the callback.
 		 */
-		constructor(callback: () => Thenable<Pseudoterminal>);
+		constructor(callback: (resolvedDefinition: TaskDefinition) => Thenable<Pseudoterminal>);
 	}
 
 	/**

src/vs/vscode.proposed.d.ts

@@ -981,7 +981,6 @@ declare module 'vscode' {
 	}
 	//#endregion
 
-	//#region CustomExecution: https://github.com/microsoft/vscode/issues/81007
 	/**
 	 * A task to execute
 	 */
@@ -989,19 +988,6 @@ declare module 'vscode' {
 		detail?: string;
 	}
 
-	export class CustomExecution2 extends CustomExecution {
-		/**
-		 * Constructs a CustomExecution task object. The callback will be executed the task is run, at which point the
-		 * extension should return the Pseudoterminal it will "run in". The task should wait to do further execution until
-		 * [Pseudoterminal.open](#Pseudoterminal.open) is called. Task cancellation should be handled using
-		 * [Pseudoterminal.close](#Pseudoterminal.close). When the task is complete fire
-		 * [Pseudoterminal.onDidClose](#Pseudoterminal.onDidClose).
-		 * @param callback The callback that will be called when the task is started by a user.
-		 */
-		constructor(callback: (resolvedDefinition: TaskDefinition) => Thenable<Pseudoterminal>);
-	}
-	//#endregion
-
 	//#region Task presentation group: https://github.com/microsoft/vscode/issues/47265
 	export interface TaskPresentationOptions {
 		/**

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

@@ -418,8 +418,8 @@ export class MainThreadTask implements MainThreadTaskShape {
 			const task = event.__task!;
 			if (event.kind === TaskEventKind.Start) {
 				const execution = TaskExecutionDTO.from(task.getTaskExecution());
-				let resolvedDefinition: TaskDefinitionDTO | undefined;
-				if (execution.task && execution.task.execution && CustomExecutionDTO.is(execution.task.execution) && event.resolvedVariables) {
+				let resolvedDefinition: TaskDefinitionDTO = execution.task!.definition;
+				if (execution.task?.execution && CustomExecutionDTO.is(execution.task.execution) && event.resolvedVariables) {
 					const dictionary: IStringDictionary<string> = {};
 					Array.from(event.resolvedVariables.entries()).forEach(entry => dictionary[entry[0]] = entry[1]);
 					resolvedDefinition = await this._configurationResolverService.resolveAny(task.getWorkspaceFolder(),

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

@@ -1039,7 +1039,6 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			ExtensionMode: extHostTypes.ExtensionMode,
 			ExtensionRuntime: extHostTypes.ExtensionRuntime,
 			CustomExecution: extHostTypes.CustomExecution,
-			CustomExecution2: extHostTypes.CustomExecution,
 			FileChangeType: extHostTypes.FileChangeType,
 			FileSystemError: extHostTypes.FileSystemError,
 			FileType: files.FileType,

src/vs/workbench/api/common/extHost.protocol.ts

@@ -1449,7 +1449,7 @@ export interface ExtHostSCMShape {
 export interface ExtHostTaskShape {
 	$provideTasks(handle: number, validTypes: { [key: string]: boolean; }): Thenable<tasks.TaskSetDTO>;
 	$resolveTask(handle: number, taskDTO: tasks.TaskDTO): Thenable<tasks.TaskDTO | undefined>;
-	$onDidStartTask(execution: tasks.TaskExecutionDTO, terminalId: number, resolvedDefinition?: tasks.TaskDefinitionDTO): void;
+	$onDidStartTask(execution: tasks.TaskExecutionDTO, terminalId: number, resolvedDefinition: tasks.TaskDefinitionDTO): void;
 	$onDidStartTaskProcess(value: tasks.TaskProcessStartedDTO): void;
 	$onDidEndTaskProcess(value: tasks.TaskProcessEndedDTO): void;
 	$OnDidEndTask(execution: tasks.TaskExecutionDTO): void;

src/vs/workbench/api/common/extHostTask.ts

@@ -475,7 +475,7 @@ export abstract class ExtHostTaskBase implements ExtHostTaskShape, IExtHostTask
 		return this._onDidExecuteTask.event;
 	}
 
-	public async $onDidStartTask(execution: tasks.TaskExecutionDTO, terminalId: number, resolvedDefinition?: tasks.TaskDefinitionDTO): Promise<void> {
+	public async $onDidStartTask(execution: tasks.TaskExecutionDTO, terminalId: number, resolvedDefinition: tasks.TaskDefinitionDTO): Promise<void> {
 		const customExecution: types.CustomExecution | undefined = this._providedCustomExecutions2.get(execution.id);
 		if (customExecution) {
 			if (this._activeCustomExecutions2.get(execution.id) !== undefined) {

src/vs/workbench/api/common/extHostTypes.ts

@@ -1831,20 +1831,20 @@ export enum TaskScope {
 	Workspace = 2
 }
 
-export class CustomExecution implements vscode.CustomExecution2 {
-	private _callback: (resolvedDefintion?: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>;
-	constructor(callback: (resolvedDefintion?: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
+export class CustomExecution implements vscode.CustomExecution {
+	private _callback: (resolvedDefintion: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>;
+	constructor(callback: (resolvedDefintion: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
 		this._callback = callback;
 	}
 	public computeId(): string {
 		return 'customExecution' + generateUuid();
 	}
 
-	public set callback(value: (resolvedDefintion?: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
+	public set callback(value: (resolvedDefintion: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
 		this._callback = value;
 	}
 
-	public get callback(): ((resolvedDefintion?: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
+	public get callback(): ((resolvedDefintion: vscode.TaskDefinition) => Thenable<vscode.Pseudoterminal>) {
 		return this._callback;
 	}
 }