Add onDidChangeShell event to the API

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

@@ -309,6 +309,9 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			get shell() {
 				return extHostTerminalService.getDefaultShell(false);
 			},
+			get onDidChangeShell() {
+				return extHostTerminalService.onDidChangeShell;
+			},
 			get isTelemetryEnabled() {
 				return extHostTelemetry.getTelemetryConfiguration();
 			},

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

@@ -37,6 +37,7 @@ export interface IExtHostTerminalService extends ExtHostTerminalServiceShape, ID
 	onDidChangeTerminalDimensions: Event<vscode.TerminalDimensionsChangeEvent>;
 	onDidChangeTerminalState: Event<vscode.Terminal>;
 	onDidWriteTerminalData: Event<vscode.TerminalDataWriteEvent>;
+	onDidChangeShell: Event<string>;
 
 	createTerminal(name?: string, shellPath?: string, shellArgs?: readonly string[] | string): vscode.Terminal;
 	createTerminalFromOptions(options: vscode.TerminalOptions, internalOptions?: ITerminalInternalOptions): vscode.Terminal;
@@ -376,6 +377,8 @@ export abstract class BaseExtHostTerminalService extends Disposable implements I
 	readonly onDidChangeTerminalState = this._onDidChangeTerminalState.event;
 	protected readonly _onDidWriteTerminalData: Emitter<vscode.TerminalDataWriteEvent>;
 	get onDidWriteTerminalData(): Event<vscode.TerminalDataWriteEvent> { return this._onDidWriteTerminalData.event; }
+	protected readonly _onDidChangeShell: Emitter<string> = new Emitter();
+	get onDidChangeShell(): Event<string> { return this._onDidChangeShell.event; }
 
 	constructor(
 		supportsProcesses: boolean,
@@ -809,8 +812,12 @@ export abstract class BaseExtHostTerminalService extends Disposable implements I
 	}
 
 	public $acceptDefaultProfile(profile: ITerminalProfile, automationProfile: ITerminalProfile): void {
+		const oldProfile = this._defaultProfile;
 		this._defaultProfile = profile;
 		this._defaultAutomationProfile = automationProfile;
+		if (oldProfile?.path !== profile.path) {
+			this._onDidChangeShell.fire(profile.path);
+		}
 	}
 
 	private _setEnvironmentVariableCollection(extensionIdentifier: string, collection: EnvironmentVariableCollection): void {

src/vscode-dts/vscode.proposed.envShellEvent.d.ts

@@ -0,0 +1,16 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+declare module 'vscode' {
+
+	// See https://github.com/microsoft/vscode/issues/160694
+	export namespace env {
+
+		/**
+		 * An {@link Event} which fires when the default shell changes.
+		 */
+		export const onDidChangeShell: Event<string>;
+	}
+}