Strict null fixes related to activeEditor now possibly being undefined

src/vs/workbench/browser/parts/editor/editorCommands.ts

@@ -422,7 +422,7 @@ export function splitEditor(editorGroupService: IEditorGroupsService, direction:
 	const newGroup = editorGroupService.addGroup(sourceGroup, direction);
 
 	// Split editor (if it can be split)
-	let editorToCopy: IEditorInput;
+	let editorToCopy: IEditorInput | null;
 	if (context && typeof context.editorIndex === 'number') {
 		editorToCopy = sourceGroup.getEditor(context.editorIndex);
 	} else {

src/vs/workbench/browser/parts/editor/editorControl.ts

@@ -53,8 +53,8 @@ export class EditorControl extends Disposable {
 		this.editorOperation = this._register(new LongRunningOperation(progressService));
 	}
 
-	get activeControl(): IActiveEditor {
-		return this._activeControl;
+	get activeControl(): IActiveEditor | null {
+		return this._activeControl as IActiveEditor | null;
 	}
 
 	openEditor(editor: EditorInput, options?: EditorOptions): Promise<IOpenEditorResult> {

src/vs/workbench/browser/parts/editor/tabsTitleControl.ts

@@ -562,7 +562,7 @@ export class TabsTitleControl extends TitleControl {
 		disposables.push(addDisposableListener(tab, EventType.DBLCLICK, (e: MouseEvent) => {
 			EventHelper.stop(e);
 
-			this.group.pinEditor(this.group.getEditor(index));
+			this.group.pinEditor(this.group.getEditor(index) || undefined);
 		}));
 
 		// Context menu
@@ -670,7 +670,8 @@ export class TabsTitleControl extends TitleControl {
 
 	private updateDropFeedback(element: HTMLElement, isDND: boolean, index?: number): void {
 		const isTab = (typeof index === 'number');
-		const isActiveTab = isTab && this.group.isActive(this.group.getEditor(index));
+		const editor = typeof index === 'number' ? this.group.getEditor(index) : null;
+		const isActiveTab = isTab && !!editor && this.group.isActive(editor);
 
 		// Background
 		const noDNDBackgroundColor = isTab ? this.getColor(isActiveTab ? TAB_ACTIVE_BACKGROUND : TAB_INACTIVE_BACKGROUND) : null;
@@ -1032,7 +1033,7 @@ export class TabsTitleControl extends TitleControl {
 		}
 	}
 
-	private getTab(editor: IEditorInput): HTMLElement {
+	private getTab(editor: IEditorInput): HTMLElement | undefined {
 		const editorIndex = this.group.getIndexOfEditor(editor);
 		if (editorIndex >= 0) {
 			return this.tabsContainer.children[editorIndex] as HTMLElement;
@@ -1193,12 +1194,12 @@ registerThemingParticipant((theme: ITheme, collector: ICssStyleCollector) => {
 		const editorGroupHeaderTabsBackground = theme.getColor(EDITOR_GROUP_HEADER_TABS_BACKGROUND);
 		const editorDragAndDropBackground = theme.getColor(EDITOR_DRAG_AND_DROP_BACKGROUND);
 
-		let adjustedTabBackground: Color;
+		let adjustedTabBackground: Color | undefined;
 		if (editorGroupHeaderTabsBackground && editorBackgroundColor) {
 			adjustedTabBackground = editorGroupHeaderTabsBackground.flatten(editorBackgroundColor, editorBackgroundColor, workbenchBackground);
 		}
 
-		let adjustedTabDragBackground: Color;
+		let adjustedTabDragBackground: Color | undefined;
 		if (editorGroupHeaderTabsBackground && editorBackgroundColor && editorDragAndDropBackground && editorBackgroundColor) {
 			adjustedTabDragBackground = editorGroupHeaderTabsBackground.flatten(editorBackgroundColor, editorDragAndDropBackground, editorBackgroundColor, workbenchBackground);
 		}

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

@@ -41,7 +41,7 @@ export function getResourceForCommand(resource: URI | object, listService: IList
 		}
 	}
 
-	return toResource(editorService.activeEditor, { supportSideBySide: true });
+	return editorService.activeEditor ? toResource(editorService.activeEditor, { supportSideBySide: true }) : null;
 }
 
 export function getMultiSelectedResources(resource: URI | object, listService: IListService, editorService: IEditorService): Array<URI> {

src/vs/workbench/contrib/quickopen/browser/gotoLineHandler.ts

@@ -40,6 +40,10 @@ export class GotoLineAction extends QuickOpenAction {
 	run(): Promise<void> {
 
 		let activeTextEditorWidget = this.editorService.activeTextEditorWidget;
+		if (!activeTextEditorWidget) {
+			return Promise.resolve();
+		}
+
 		if (isDiffEditor(activeTextEditorWidget)) {
 			activeTextEditorWidget = activeTextEditorWidget.getModifiedEditor();
 		}
@@ -61,7 +65,7 @@ export class GotoLineAction extends QuickOpenAction {
 
 		if (restoreOptions) {
 			Event.once(this._quickOpenService.onHide)(() => {
-				activeTextEditorWidget.updateOptions(restoreOptions!);
+				activeTextEditorWidget!.updateOptions(restoreOptions!);
 			});
 		}
 
@@ -92,7 +96,7 @@ class GotoLineEntry extends EditorQuickOpenEntry {
 		// Inform user about valid range if input is invalid
 		const maxLineNumber = this.getMaxLineNumber();
 
-		if (this.invalidRange(maxLineNumber)) {
+		if (this.editorService.activeTextEditorWidget && this.invalidRange(maxLineNumber)) {
 			const position = this.editorService.activeTextEditorWidget.getPosition();
 			if (position) {
 				const currentLine = position.lineNumber;
@@ -115,6 +119,9 @@ class GotoLineEntry extends EditorQuickOpenEntry {
 
 	private getMaxLineNumber(): number {
 		const activeTextEditorWidget = this.editorService.activeTextEditorWidget;
+		if (!activeTextEditorWidget) {
+			return -1;
+		}
 
 		let model = activeTextEditorWidget.getModel();
 		if (model && (<IDiffEditorModel>model).modified && (<IDiffEditorModel>model).original) {
@@ -132,8 +139,8 @@ class GotoLineEntry extends EditorQuickOpenEntry {
 		return this.runPreview();
 	}
 
-	getInput(): IEditorInput {
-		return this.editorService.activeEditor;
+	getInput(): IEditorInput | null {
+		return this.editorService.activeEditor || null;
 	}
 
 	getOptions(pinned?: boolean): ITextEditorOptions {
@@ -153,7 +160,7 @@ class GotoLineEntry extends EditorQuickOpenEntry {
 		// Check for sideBySide use
 		const sideBySide = context.keymods.ctrlCmd;
 		if (sideBySide) {
-			this.editorService.openEditor(this.getInput(), this.getOptions(context.keymods.alt), SIDE_GROUP);
+			this.editorService.openEditor(this.getInput()!, this.getOptions(context.keymods.alt), SIDE_GROUP);
 		}
 
 		// Apply selection and focus
@@ -183,8 +190,8 @@ class GotoLineEntry extends EditorQuickOpenEntry {
 			activeTextEditorWidget.revealRangeInCenter(range, ScrollType.Smooth);
 
 			// Decorate if possible
-			if (types.isFunction(activeTextEditorWidget.changeDecorations)) {
-				this.handler.decorateOutline(range, activeTextEditorWidget, this.editorService.activeControl.group!);
+			if (this.editorService.activeControl && types.isFunction(activeTextEditorWidget.changeDecorations)) {
+				this.handler.decorateOutline(range, activeTextEditorWidget, this.editorService.activeControl.group);
 			}
 		}
 
@@ -236,7 +243,9 @@ export class GotoLineHandler extends QuickOpenHandler {
 		// Remember view state to be able to restore on cancel
 		if (!this.lastKnownEditorViewState) {
 			const activeTextEditorWidget = this.editorService.activeTextEditorWidget;
-			this.lastKnownEditorViewState = activeTextEditorWidget.saveViewState();
+			if (activeTextEditorWidget) {
+				this.lastKnownEditorViewState = activeTextEditorWidget.saveViewState();
+			}
 		}
 
 		return Promise.resolve(new QuickOpenModel([new GotoLineEntry(searchValue, this.editorService, this)]));

src/vs/workbench/contrib/quickopen/browser/gotoSymbolHandler.ts

@@ -288,8 +288,8 @@ class SymbolEntry extends EditorQuickOpenEntryGroup {
 		return this.range;
 	}
 
-	getInput(): IEditorInput {
-		return this.editorService.activeEditor;
+	getInput(): IEditorInput | null {
+		return this.editorService.activeEditor || null;
 	}
 
 	getOptions(pinned?: boolean): ITextEditorOptions {
@@ -312,7 +312,7 @@ class SymbolEntry extends EditorQuickOpenEntryGroup {
 		// Check for sideBySide use
 		const sideBySide = context.keymods.ctrlCmd;
 		if (sideBySide) {
-			this.editorService.openEditor(this.getInput(), this.getOptions(context.keymods.alt), SIDE_GROUP);
+			this.editorService.openEditor(this.getInput()!, this.getOptions(context.keymods.alt), SIDE_GROUP);
 		}
 
 		// Apply selection and focus
@@ -337,8 +337,8 @@ class SymbolEntry extends EditorQuickOpenEntryGroup {
 			activeTextEditorWidget.revealRangeInCenter(range, ScrollType.Smooth);
 
 			// Decorate if possible
-			if (types.isFunction(activeTextEditorWidget.changeDecorations)) {
-				this.handler.decorateOutline(this.range, range, activeTextEditorWidget, this.editorService.activeControl.group!);
+			if (this.editorService.activeControl && types.isFunction(activeTextEditorWidget.changeDecorations)) {
+				this.handler.decorateOutline(this.range, range, activeTextEditorWidget, this.editorService.activeControl.group);
 			}
 		}
 
@@ -401,7 +401,9 @@ export class GotoSymbolHandler extends QuickOpenHandler {
 		// Remember view state to be able to restore on cancel
 		if (!this.lastKnownEditorViewState) {
 			const activeTextEditorWidget = this.editorService.activeTextEditorWidget;
-			this.lastKnownEditorViewState = activeTextEditorWidget.saveViewState();
+			if (activeTextEditorWidget) {
+				this.lastKnownEditorViewState = activeTextEditorWidget.saveViewState();
+			}
 		}
 
 		// Resolve Outline Model

src/vs/workbench/services/history/browser/history.ts

@@ -217,7 +217,7 @@ export class HistoryService extends Disposable implements IHistoryService {
 			// Track the last edit location by tracking model content change events
 			// Use a debouncer to make sure to capture the correct cursor position
 			// after the model content has changed.
-			this.activeEditorListeners.push(Event.debounce(activeTextEditorWidget.onDidChangeModelContent, (last, event) => event, 0)((event => this.rememberLastEditLocation(activeEditor, activeTextEditorWidget))));
+			this.activeEditorListeners.push(Event.debounce(activeTextEditorWidget.onDidChangeModelContent, (last, event) => event, 0)((event => this.rememberLastEditLocation(activeEditor!, activeTextEditorWidget))));
 		}
 	}