Make sure active instance changed fires when switching groups

Fixes microsoft#127357

Author: Tyriar

src/vs/workbench/contrib/terminal/browser/terminal.ts

@@ -82,7 +82,7 @@ export interface ITerminalGroup {
 	focusNextPane(): void;
 	resizePane(direction: Direction): void;
 	resizePanes(relativeSizes: number[]): void;
-	setActiveInstanceByIndex(index: number): void;
+	setActiveInstanceByIndex(index: number, force?: boolean): void;
 	attachToElement(element: HTMLElement): void;
 	addInstance(instance: ITerminalInstance): void;
 	removeInstance(instance: ITerminalInstance): void;
@@ -217,7 +217,6 @@ export interface ITerminalGroupService extends ITerminalInstanceHost, ITerminalF
 	readonly groups: readonly ITerminalGroup[];
 	activeGroup: ITerminalGroup | undefined;
 	readonly activeGroupIndex: number;
-	readonly activeInstanceIndex: number;
 
 	readonly onDidChangeActiveGroup: Event<ITerminalGroup | undefined>;
 	readonly onDidDisposeGroup: Event<ITerminalGroup>;

src/vs/workbench/contrib/terminal/browser/terminalGroup.ts

@@ -421,16 +421,18 @@ export class TerminalGroup extends Disposable implements ITerminalGroup {
 		return terminalIndex;
 	}
 
-	setActiveInstanceByIndex(index: number): void {
+	setActiveInstanceByIndex(index: number, force?: boolean): void {
 		// Check for invalid value
 		if (index < 0 || index >= this._terminalInstances.length) {
 			return;
 		}
 
-		const oldActiveGroup = this.activeInstance;
+		const oldActiveInstance = this.activeInstance;
 		this._activeInstanceIndex = index;
-		if (oldActiveGroup !== this.activeInstance) {
-			this._onInstancesChanged.fire();
+		if (force) {
+			if (oldActiveInstance !== this.activeInstance) {
+				this._onInstancesChanged.fire();
+			}
 			this._onDidChangeActiveInstance.fire(this.activeInstance);
 		}
 	}

src/vs/workbench/contrib/terminal/browser/terminalGroupService.ts

@@ -28,7 +28,6 @@ export class TerminalGroupService extends Disposable implements ITerminalGroupSe
 	get instances(): ITerminalInstance[] {
 		return this.groups.reduce((p, c) => p.concat(c.terminalInstances), [] as ITerminalInstance[]);
 	}
-	activeInstanceIndex: number = -1;
 
 	private _terminalGroupCountContextKey: IContextKey<number>;
 	private _terminalCountContextKey: IContextKey<number>;
@@ -105,10 +104,11 @@ export class TerminalGroupService extends Disposable implements ITerminalGroupSe
 	}
 	set activeGroup(value: ITerminalGroup | undefined) {
 		if (value === undefined) {
-			this.activeGroupIndex = -1;
+			// Setting to undefined is not possible, this can only be done when removing the last group
 			return;
 		}
-		this.activeGroupIndex = this.groups.findIndex(e => e === value);
+		const index = this.groups.findIndex(e => e === value);
+		this.setActiveGroupByIndex(index);
 	}
 
 	get activeInstance(): ITerminalInstance | undefined {
@@ -233,13 +233,10 @@ export class TerminalGroupService extends Disposable implements ITerminalGroupSe
 		}
 
 		this._onDidChangeInstances.fire();
-		if (this.groups.length === 0) {
-			this._onDidChangeActiveInstance.fire(undefined);
-		}
-
 		this._onDidChangeGroups.fire();
 		if (wasActiveGroup) {
 			this._onDidChangeActiveGroup.fire(this.activeGroup);
+			this._onDidChangeActiveInstance.fire(this.activeInstance);
 		}
 	}
 
@@ -248,7 +245,7 @@ export class TerminalGroupService extends Disposable implements ITerminalGroupSe
 	 * group has been removed.
 	 */
 	setActiveGroupByIndex(index: number, force?: boolean) {
-		if (index >= this.groups.length) {
+		if (index < 0 || index >= this.groups.length) {
 			return;
 		}
 		const oldActiveGroup = this.activeGroup;
@@ -287,16 +284,15 @@ export class TerminalGroupService extends Disposable implements ITerminalGroupSe
 			return;
 		}
 
-		this.activeInstanceIndex = instanceLocation.instanceIndex;
+		const activeInstanceIndex = instanceLocation.instanceIndex;
 
 		if (this.activeGroupIndex !== instanceLocation.groupIndex) {
 			this.activeGroupIndex = instanceLocation.groupIndex;
 			this._onDidChangeActiveGroup.fire(this.activeGroup);
+			instanceLocation.group.setActiveInstanceByIndex(activeInstanceIndex, true);
 		}
 		this.groups.forEach((g, i) => g.setVisible(i === instanceLocation.groupIndex));
 
-		instanceLocation.group.setActiveInstanceByIndex(this.activeInstanceIndex);
-		this._onDidChangeActiveInstance.fire(newActiveInstance);
 	}
 
 	setActiveGroupToNext() {

src/vs/workbench/contrib/terminal/browser/terminalView.ts

@@ -433,7 +433,7 @@ class SingleTerminalTabActionViewItem extends MenuEntryActionViewItem {
 
 		// Register listeners to update the tab
 		this._register(this._terminalService.onInstancePrimaryStatusChanged(e => this.updateLabel(e)));
-		this._register(_terminalGroupService.onDidChangeActiveInstance(() => this.updateLabel()));
+		this._register(this._terminalGroupService.onDidChangeActiveInstance(() => this.updateLabel()));
 		this._register(this._terminalService.onInstanceIconChanged(e => this.updateLabel(e)));
 		this._register(this._terminalService.onInstanceColorChanged(e => this.updateLabel(e)));
 		this._register(this._terminalService.onInstanceTitleChanged(e => {