Convert `toResource` to return undefined instead of null

src/vs/workbench/browser/labels.ts

@@ -350,7 +350,7 @@ class ResourceLabelWidget extends IconLabel {
 
 	setEditor(editor: IEditorInput, options?: IResourceLabelOptions): void {
 		this.setResource({
-			resource: withNullAsUndefined(toResource(editor, { supportSideBySide: SideBySideEditor.MASTER })),
+			resource: toResource(editor, { supportSideBySide: SideBySideEditor.MASTER }),
 			name: withNullAsUndefined(editor.getName()),
 			description: withNullAsUndefined(editor.getDescription())
 		}, options);

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

@@ -51,7 +51,7 @@ export class EditorPickerEntry extends QuickOpenEntryGroup {
 	}
 
 	getResource() {
-		return withNullAsUndefined(toResource(this.editor, { supportSideBySide: SideBySideEditor.MASTER }));
+		return toResource(this.editor, { supportSideBySide: SideBySideEditor.MASTER });
 	}
 
 	getAriaLabel(): string {

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

@@ -39,7 +39,7 @@ import { Themable } from 'vs/workbench/common/theme';
 import { IExtensionService } from 'vs/workbench/services/extensions/common/extensions';
 import { AnchorAlignment } from 'vs/base/browser/ui/contextview/contextview';
 import { IFileService } from 'vs/platform/files/common/files';
-import { withNullAsUndefined } from 'vs/base/common/types';
+import { withNullAsUndefined, withUndefinedAsNull } from 'vs/base/common/types';
 import { ILabelService } from 'vs/platform/label/common/label';
 
 export interface IToolbarActions {
@@ -221,7 +221,7 @@ export abstract class TitleControl extends Themable {
 		this.editorToolBarMenuDisposables = dispose(this.editorToolBarMenuDisposables);
 
 		// Update the resource context
-		this.resourceContext.set(this.group.activeEditor ? toResource(this.group.activeEditor, { supportSideBySide: SideBySideEditor.MASTER }) : null);
+		this.resourceContext.set(this.group.activeEditor ? withUndefinedAsNull(toResource(this.group.activeEditor, { supportSideBySide: SideBySideEditor.MASTER })) : null);
 
 		// Editor actions require the editor control to be there, so we retrieve it via service
 		const activeControl = this.group.activeControl;
@@ -288,7 +288,7 @@ export abstract class TitleControl extends Themable {
 
 		// Update the resource context
 		const currentContext = this.resourceContext.get();
-		this.resourceContext.set(toResource(editor, { supportSideBySide: SideBySideEditor.MASTER }));
+		this.resourceContext.set(withUndefinedAsNull(toResource(editor, { supportSideBySide: SideBySideEditor.MASTER })));
 
 		// Find target anchor
 		let anchor: HTMLElement | { x: number, y: number } = node;

src/vs/workbench/common/editor.ts

@@ -5,7 +5,7 @@
 
 import { Event, Emitter } from 'vs/base/common/event';
 import { assign } from 'vs/base/common/objects';
-import { isUndefinedOrNull, withUndefinedAsNull } from 'vs/base/common/types';
+import { isUndefinedOrNull } from 'vs/base/common/types';
 import { URI } from 'vs/base/common/uri';
 import { IDisposable, Disposable } from 'vs/base/common/lifecycle';
 import { IEditor as ICodeEditor, IEditorViewState, ScrollType, IDiffEditor } from 'vs/editor/common/editorCommon';
@@ -1002,9 +1002,9 @@ export interface IResourceOptions {
 	filterByScheme?: string | string[];
 }
 
-export function toResource(editor: IEditorInput | null | undefined, options?: IResourceOptions): URI | null {
+export function toResource(editor: IEditorInput | undefined, options?: IResourceOptions): URI | undefined {
 	if (!editor) {
-		return null;
+		return undefined;
 	}
 
 	if (options && options.supportSideBySide && editor instanceof SideBySideEditorInput) {
@@ -1013,7 +1013,7 @@ export function toResource(editor: IEditorInput | null | undefined, options?: IR
 
 	const resource = editor.getResource();
 	if (!resource || !options || !options.filterByScheme) {
-		return withUndefinedAsNull(resource);
+		return resource;
 	}
 
 	if (Array.isArray(options.filterByScheme) && options.filterByScheme.some(scheme => resource.scheme === scheme)) {
@@ -1024,7 +1024,7 @@ export function toResource(editor: IEditorInput | null | undefined, options?: IR
 		return resource;
 	}
 
-	return null;
+	return undefined;
 }
 
 export const enum CloseDirection {

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

@@ -43,6 +43,7 @@ import { IDisposable, dispose } from 'vs/base/common/lifecycle';
 import { IWorkbenchEnvironmentService } from 'vs/workbench/services/environment/common/environmentService';
 import { IEnvironmentService } from 'vs/platform/environment/common/environment';
 import { UNTITLED_WORKSPACE_NAME } from 'vs/platform/workspaces/common/workspaces';
+import { withUndefinedAsNull } from 'vs/base/common/types';
 
 // Commands
 
@@ -349,7 +350,7 @@ KeybindingsRegistry.registerCommandAndKeybindingRule({
 	}
 });
 
-let globalResourceToCompare: URI | null;
+let globalResourceToCompare: URI | undefined;
 let resourceSelectedForCompareContext: IContextKey<boolean>;
 CommandsRegistry.registerCommand({
 	id: SELECT_FOR_COMPARE_COMMAND_ID,
@@ -524,9 +525,9 @@ KeybindingsRegistry.registerCommandAndKeybindingRule({
 		const editorService = accessor.get(IEditorService);
 		let resource: URI | null = null;
 		if (resourceOrObject && 'from' in resourceOrObject && resourceOrObject.from === 'menu') {
-			resource = toResource(editorService.activeEditor);
+			resource = withUndefinedAsNull(toResource(editorService.activeEditor));
 		} else {
-			resource = getResourceForCommand(resourceOrObject, accessor.get(IListService), editorService);
+			resource = withUndefinedAsNull(getResourceForCommand(resourceOrObject, accessor.get(IListService), editorService));
 		}
 
 		return save(resource, true, undefined, editorService, accessor.get(IFileService), accessor.get(IUntitledEditorService), accessor.get(ITextFileService), accessor.get(IEditorGroupsService), accessor.get(IWorkbenchEnvironmentService));

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

@@ -14,7 +14,7 @@ import { coalesce } from 'vs/base/common/arrays';
 
 // Commands can get exeucted from a command pallete, from a context menu or from some list using a keybinding
 // To cover all these cases we need to properly compute the resource on which the command is being executed
-export function getResourceForCommand(resource: URI | object | undefined, listService: IListService, editorService: IEditorService): URI | null {
+export function getResourceForCommand(resource: URI | object | undefined, listService: IListService, editorService: IEditorService): URI | undefined {
 	if (URI.isUri(resource)) {
 		return resource;
 	}
@@ -41,7 +41,7 @@ export function getResourceForCommand(resource: URI | object | undefined, listSe
 		}
 	}
 
-	return editorService.activeEditor ? toResource(editorService.activeEditor, { supportSideBySide: SideBySideEditor.MASTER }) : null;
+	return editorService.activeEditor ? toResource(editorService.activeEditor, { supportSideBySide: SideBySideEditor.MASTER }) : undefined;
 }
 
 export function getMultiSelectedResources(resource: URI | object | undefined, listService: IListService, editorService: IEditorService): Array<URI> {

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

@@ -41,7 +41,7 @@ import { IDragAndDropData, DataTransfers } from 'vs/base/browser/dnd';
 import { memoize } from 'vs/base/common/decorators';
 import { ElementsDragAndDropData, DesktopDragAndDropData } from 'vs/base/browser/ui/list/listView';
 import { URI } from 'vs/base/common/uri';
-import { withNullAsUndefined } from 'vs/base/common/types';
+import { withNullAsUndefined, withUndefinedAsNull } from 'vs/base/common/types';
 
 const $ = dom.$;
 
@@ -245,7 +245,7 @@ export class OpenEditorsView extends ViewletPanel {
 			const element = e.elements.length ? e.elements[0] : undefined;
 			if (element instanceof OpenEditor) {
 				this.dirtyEditorFocusedContext.set(this.textFileService.isDirty(withNullAsUndefined(element.getResource())));
-				this.resourceContext.set(element.getResource());
+				this.resourceContext.set(withUndefinedAsNull(element.getResource()));
 			} else if (!!element) {
 				this.groupFocusedContext.set(true);
 			}

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

@@ -258,7 +258,7 @@ export class OpenEditor implements IEditorIdentifier {
 		return this.editor.isDirty();
 	}
 
-	public getResource(): URI | null {
+	public getResource(): URI | undefined {
 		return toResource(this.editor, { supportSideBySide: SideBySideEditor.MASTER });
 	}
 }

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

@@ -958,7 +958,7 @@ export class HistoryService extends Disposable implements IHistoryService {
 	getLastActiveFile(filterByScheme: string): URI | undefined {
 		const history = this.getHistory();
 		for (const input of history) {
-			let resource: URI | null;
+			let resource: URI | undefined;
 			if (input instanceof EditorInput) {
 				resource = toResource(input, { filterByScheme });
 			} else {