enable TS strict mode

configs/base.tsconfig.json

@@ -8,7 +8,7 @@
     "noEmitOnError": false,
     "noImplicitThis": true,
     "noUnusedLocals": true,
-    "strictNullChecks": true,
+    "strict": true,
     "experimentalDecorators": true,
     "emitDecoratorMetadata": true,
     "downlevelIteration": true,

dev-packages/application-package/src/application-package.ts

@@ -24,12 +24,12 @@ import deepmerge = require('deepmerge');
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type ApplicationLog = (message?: any, ...optionalParams: any[]) => void;
-export class ApplicationPackageOptions {
-    readonly projectPath: string;
-    readonly log?: ApplicationLog;
-    readonly error?: ApplicationLog;
-    readonly registry?: NpmRegistry;
-    readonly appTarget?: ApplicationProps.Target;
+export interface ApplicationPackageOptions {
+    readonly projectPath: string
+    readonly log?: ApplicationLog
+    readonly error?: ApplicationLog
+    readonly registry?: NpmRegistry
+    readonly appTarget?: ApplicationProps.Target
 }
 
 export type ApplicationModuleResolver = (modulePath: string) => string;

dev-packages/application-package/src/extension-package-collector.ts

@@ -28,7 +28,7 @@ export class ExtensionPackageCollector {
         protected readonly resolveModule: (modulePath: string) => string
     ) { }
 
-    protected root: NodePackage;
+    protected root?: NodePackage;
     collect(pck: NodePackage): ReadonlyArray<ExtensionPackage> {
         this.root = pck;
         this.collectPackages(pck);
@@ -73,7 +73,7 @@ export class ExtensionPackageCollector {
         if (RawExtensionPackage.is(pck)) {
             const parent = this.parent;
             const version = pck.version;
-            const transitive = !(name in this.root.dependencies!);
+            const transitive = !(name in this.root!.dependencies!);
             pck.installed = { packagePath, version, parent, transitive };
             pck.version = versionRange;
             const extensionPackage = this.extensionPackageFactory(pck, { alias: name });

dev-packages/application-package/src/npm-registry.ts

@@ -84,7 +84,7 @@ export class NpmRegistryOptions {
     /**
      * Default: false.
      */
-    readonly watchChanges: boolean;
+    readonly watchChanges: boolean = false;
 }
 
 export class NpmRegistry {

examples/api-samples/src/browser/file-watching/sample-file-watching-contribution.ts

@@ -50,19 +50,19 @@ const FileWatchingPreferencesSchema: PreferenceSchema = {
 @injectable()
 class SampleFileWatchingContribution implements FrontendApplicationContribution {
 
-    protected verbose: boolean;
+    protected verbose: boolean = false;
 
     @inject(FileService)
-    protected readonly fileService: FileService;
+    protected readonly fileService!: FileService;
 
     @inject(LabelProvider)
-    protected readonly labelProvider: LabelProvider;
+    protected readonly labelProvider!: LabelProvider;
 
     @inject(WorkspaceService)
-    protected readonly workspaceService: WorkspaceService;
+    protected readonly workspaceService!: WorkspaceService;
 
     @inject(FileWatchingPreferences)
-    protected readonly fileWatchingPreferences: FileWatchingPreferences;
+    protected readonly fileWatchingPreferences!: FileWatchingPreferences;
 
     @postConstruct()
     protected postConstruct(): void {

examples/api-samples/src/browser/label/sample-dynamic-label-provider-command-contribution.ts

@@ -32,7 +32,7 @@ export namespace ExampleLabelProviderCommands {
 export class SampleDynamicLabelProviderCommandContribution implements FrontendApplicationContribution, CommandContribution {
 
     @inject(SampleDynamicLabelProviderContribution)
-    protected readonly labelProviderContribution: SampleDynamicLabelProviderContribution;
+    protected readonly labelProviderContribution!: SampleDynamicLabelProviderContribution;
 
     initialize(): void { }
 

examples/api-samples/src/browser/menu/sample-menu-contribution.ts

@@ -39,10 +39,10 @@ const SampleQuickInputCommand: Command = {
 export class SampleCommandContribution implements CommandContribution {
 
     @inject(QuickInputService)
-    protected readonly quickInputService: QuickInputService;
+    protected readonly quickInputService!: QuickInputService;
 
     @inject(MessageService)
-    protected readonly messageService: MessageService;
+    protected readonly messageService!: MessageService;
 
     registerCommands(commands: CommandRegistry): void {
         commands.registerCommand(SampleCommand, {

examples/api-samples/src/browser/output/sample-output-channel-with-severity.ts

@@ -21,7 +21,7 @@ import { OutputChannelManager, OutputChannelSeverity } from '@theia/output/lib/b
 export class SampleOutputChannelWithSeverity
     implements FrontendApplicationContribution {
     @inject(OutputChannelManager)
-    protected readonly outputChannelManager: OutputChannelManager;
+    protected readonly outputChannelManager!: OutputChannelManager;
     public onStart(): void {
         const channel = this.outputChannelManager.getChannel('API Sample: my test channel');
         channel.appendLine('hello info1'); // showed without color

examples/api-samples/src/browser/view/sample-unclosable-view-contribution.ts

@@ -33,7 +33,7 @@ export class SampleUnclosableViewContribution extends AbstractViewContribution<S
 
     protected toolbarItemState = false;
 
-    @inject(MessageService) protected readonly messageService: MessageService;
+    @inject(MessageService) protected readonly messageService!: MessageService;
 
     constructor() {
         super({

examples/api-samples/src/browser/vsx/sample-vsx-command-contribution.ts

@@ -22,10 +22,10 @@ import { Command, CommandContribution, CommandRegistry, MessageService } from '@
 export class VSXCommandContribution implements CommandContribution {
 
     @inject(MessageService)
-    protected readonly messageService: MessageService;
+    protected readonly messageService!: MessageService;
 
     @inject(VSXEnvironment)
-    protected readonly environment: VSXEnvironment;
+    protected readonly environment!: VSXEnvironment;
 
     protected readonly command: Command = {
         id: 'vsx.echo-api-version',

examples/api-samples/src/electron-browser/updater/sample-updater-frontend-contribution.ts

@@ -84,7 +84,7 @@ export class SampleUpdaterClientImpl implements SampleUpdaterClient {
 export class ElectronMenuUpdater {
 
     @inject(ElectronMainMenuFactory)
-    protected readonly factory: ElectronMainMenuFactory;
+    protected readonly factory!: ElectronMainMenuFactory;
 
     public update(): void {
         this.setMenu();
@@ -104,16 +104,16 @@ export class ElectronMenuUpdater {
 export class SampleUpdaterFrontendContribution implements CommandContribution, MenuContribution {
 
     @inject(MessageService)
-    protected readonly messageService: MessageService;
+    protected readonly messageService!: MessageService;
 
     @inject(ElectronMenuUpdater)
-    protected readonly menuUpdater: ElectronMenuUpdater;
+    protected readonly menuUpdater!: ElectronMenuUpdater;
 
     @inject(SampleUpdater)
-    protected readonly updater: SampleUpdater;
+    protected readonly updater!: SampleUpdater;
 
     @inject(SampleUpdaterClientImpl)
-    protected readonly updaterClient: SampleUpdaterClientImpl;
+    protected readonly updaterClient!: SampleUpdaterClientImpl;
 
     protected readyToUpdate = false;
 

packages/bulk-edit/src/browser/bulk-edit-contribution.ts

@@ -27,10 +27,10 @@ import { nls } from '@theia/core/lib/common/nls';
 
 @injectable()
 export class BulkEditContribution extends AbstractViewContribution<BulkEditTreeWidget> implements TabBarToolbarContribution {
-    private edits: monaco.editor.ResourceEdit[];
+    private edits?: monaco.editor.ResourceEdit[];
 
     @inject(QuickViewService) @optional()
-    protected readonly quickView: QuickViewService;
+    protected readonly quickView?: QuickViewService;
 
     constructor(private readonly bulkEditService: MonacoBulkEditService) {
         super({

packages/bulk-edit/src/browser/bulk-edit-tree-label-provider.ts

@@ -24,13 +24,13 @@ import { WorkspaceService } from '@theia/workspace/lib/browser';
 export class BulkEditTreeLabelProvider implements LabelProviderContribution {
 
     @inject(LabelProvider)
-    protected readonly labelProvider: LabelProvider;
+    protected readonly labelProvider!: LabelProvider;
 
     @inject(TreeLabelProvider)
-    protected readonly treeLabelProvider: TreeLabelProvider;
+    protected readonly treeLabelProvider!: TreeLabelProvider;
 
     @inject(WorkspaceService)
-    protected readonly workspaceService: WorkspaceService;
+    protected readonly workspaceService!: WorkspaceService;
 
     canHandle(element: object): number {
         return BulkEditInfoNode.is(element) ?

packages/bulk-edit/src/browser/bulk-edit-tree/bulk-edit-tree-model.ts

@@ -20,8 +20,8 @@ import { TreeModelImpl, OpenerService, open, TreeNode } from '@theia/core/lib/br
 
 @injectable()
 export class BulkEditTreeModel extends TreeModelImpl {
-    @inject(BulkEditTree) protected readonly tree: BulkEditTree;
-    @inject(OpenerService) protected readonly openerService: OpenerService;
+    @inject(BulkEditTree) protected readonly tree!: BulkEditTree;
+    @inject(OpenerService) protected readonly openerService!: OpenerService;
 
     protected doOpenNode(node: TreeNode): void {
         if (BulkEditNode.is(node)) {

packages/bulk-edit/src/browser/bulk-edit-tree/bulk-edit-tree-widget.tsx

@@ -37,13 +37,13 @@ export class BulkEditTreeWidget extends TreeWidget {
     private editorWidgets: EditorWidget[] = [];
 
     @inject(FileResourceResolver)
-    protected readonly fileResourceResolver: FileResourceResolver;
+    protected readonly fileResourceResolver!: FileResourceResolver;
 
     @inject(EditorManager)
-    protected readonly editorManager: EditorManager;
+    protected readonly editorManager!: EditorManager;
 
     @inject(QuickViewService) @optional()
-    protected readonly quickView: QuickViewService;
+    protected readonly quickView?: QuickViewService;
 
     constructor(
         @inject(TreeProps) readonly treeProps: TreeProps,
@@ -185,7 +185,7 @@ export class BulkEditTreeWidget extends TreeWidget {
         let lines: string[] = [];
         if (bulkEditInfoNode?.fileContents) {
             lines = bulkEditInfoNode.fileContents.split('\n');
-            bulkEditInfoNode.children.map((node: BulkEditNode) => {
+            (bulkEditInfoNode.children as BulkEditNode[]).map(node => {
                 if (node.bulkEdit && ('textEdit' in node.bulkEdit)) {
                     const startLineNum = node.bulkEdit.textEdit.range.startLineNumber;
                     if (lines.length > startLineNum) {

packages/bulk-edit/src/browser/bulk-edit-tree/bulk-edit-tree.ts

@@ -39,7 +39,7 @@ export class BulkEditTree extends TreeImpl {
             bulkEditInfos = edits
                 .map(edit => this.getResourcePath(edit))
                 .filter((path, index, arr) => path && arr.indexOf(path) === index)
-                .map((path: string) => this.createBulkEditInfo(path, new URI(path), fileContentsMap.get(path)))
+                .map(path => this.createBulkEditInfo(path as string, new URI(path), fileContentsMap.get(path as string)))
                 .filter(Boolean);
 
             if (bulkEditInfos.length > 0) {

packages/callhierarchy/src/browser/callhierarchy-contribution.ts

@@ -36,8 +36,8 @@ export namespace CallHierarchyCommands {
 @injectable()
 export class CallHierarchyContribution extends AbstractViewContribution<CallHierarchyTreeWidget> {
 
-    @inject(CurrentEditorAccess) protected readonly editorAccess: CurrentEditorAccess;
-    @inject(CallHierarchyServiceProvider) protected readonly callHierarchyServiceProvider: CallHierarchyServiceProvider;
+    @inject(CurrentEditorAccess) protected readonly editorAccess!: CurrentEditorAccess;
+    @inject(CallHierarchyServiceProvider) protected readonly callHierarchyServiceProvider!: CallHierarchyServiceProvider;
     constructor() {
         super({
             widgetId: CALLHIERARCHY_ID,

packages/callhierarchy/src/browser/callhierarchy-service.ts

@@ -37,7 +37,7 @@ export interface CallHierarchyService {
 export class CallHierarchyServiceProvider {
 
     @inject(ContributionProvider) @named(CallHierarchyService)
-    protected readonly contributions: ContributionProvider<CallHierarchyService>;
+    protected readonly contributions!: ContributionProvider<CallHierarchyService>;
 
     private services: CallHierarchyService[] = [];
 

packages/callhierarchy/src/browser/callhierarchy-tree/callhierarchy-tree-model.ts

@@ -27,8 +27,8 @@ export class CallHierarchyTreeModel extends TreeModelImpl {
 
     private _languageId: string | undefined;
 
-    @inject(CallHierarchyTree) protected readonly tree: CallHierarchyTree;
-    @inject(CallHierarchyServiceProvider) protected readonly callHierarchyServiceProvider: CallHierarchyServiceProvider;
+    @inject(CallHierarchyTree) protected readonly tree!: CallHierarchyTree;
+    @inject(CallHierarchyServiceProvider) protected readonly callHierarchyServiceProvider!: CallHierarchyServiceProvider;
 
     getTree(): CallHierarchyTree {
         return this.tree;

packages/callhierarchy/src/browser/current-editor-access.ts

@@ -24,7 +24,7 @@ import { Location } from '@theia/core/shared/vscode-languageserver-types';
 @injectable()
 export class CurrentEditorAccess {
 
-    @inject(EditorManager) protected readonly editorManager: EditorManager;
+    @inject(EditorManager) protected readonly editorManager!: EditorManager;
 
     getSelection(): Location | undefined {
         const activeEditor = this.getCurrentEditor();

packages/callhierarchy/src/common/glob.ts

@@ -588,6 +588,7 @@ function parsedExpression(expression: IExpression, options: IGlobOptions): Parse
 
     if (!parsedPatterns.some(parsedPattern => (<ParsedExpressionPattern>parsedPattern).requiresSiblings!)) {
         if (n === 1) {
+            // @ts-expect-error TS2322
             return <ParsedStringPattern>parsedPatterns[0];
         }
 
@@ -618,6 +619,7 @@ function parsedExpression(expression: IExpression, options: IGlobOptions): Parse
             resultExpression.allPaths = allPaths;
         }
 
+        // @ts-expect-error TS2322
         return resultExpression;
     }
 
@@ -655,6 +657,7 @@ function parsedExpression(expression: IExpression, options: IGlobOptions): Parse
         resultExpression.allPaths = allPaths;
     }
 
+    // @ts-expect-error TS2322
     return resultExpression;
 }
 

packages/console/src/browser/console-contribution.ts

@@ -53,7 +53,7 @@ export namespace ConsoleContextMenu {
 export class ConsoleContribution implements FrontendApplicationContribution, CommandContribution, KeybindingContribution, MenuContribution {
 
     @inject(ConsoleManager)
-    protected readonly manager: ConsoleManager;
+    protected readonly manager!: ConsoleManager;
 
     initialize(): void { }
 

packages/console/src/browser/console-keybinding-contexts.ts

@@ -49,7 +49,7 @@ export class ConsoleInputFocusContext implements KeybindingContext {
     readonly id: string = ConsoleKeybindingContexts.consoleInputFocus;
 
     @inject(ConsoleManager)
-    protected readonly manager: ConsoleManager;
+    protected readonly manager!: ConsoleManager;
 
     isEnabled(): boolean {
         const console = this.manager.activeConsole;

packages/console/src/browser/console-manager.ts

@@ -22,7 +22,7 @@ import { ConsoleWidget } from './console-widget';
 export class ConsoleManager {
 
     @inject(ApplicationShell)
-    protected readonly shell: ApplicationShell;
+    protected readonly shell!: ApplicationShell;
 
     get activeConsole(): ConsoleWidget | undefined {
         const widget = this.shell.activeWidget;

packages/console/src/browser/console-session.ts

@@ -39,7 +39,7 @@ export abstract class ConsoleSession extends TreeSource {
     protected selectedSeverity?: Severity;
     protected readonly selectionEmitter: Emitter<void> = new Emitter<void>();
     readonly onSelectionChange = this.selectionEmitter.event;
-    id: string;
+    abstract id: string;
 
     get severity(): Severity | undefined {
         return this.selectedSeverity;

packages/console/src/browser/console-widget.ts

@@ -60,21 +60,21 @@ export class ConsoleWidget extends BaseWidget implements StatefulWidget {
     }
 
     @inject(ConsoleOptions)
-    protected readonly options: ConsoleOptions;
+    protected readonly options!: ConsoleOptions;
 
     @inject(ConsoleContentWidget)
-    readonly content: ConsoleContentWidget;
+    readonly content!: ConsoleContentWidget;
 
     @inject(ConsoleHistory)
-    protected readonly history: ConsoleHistory;
+    protected readonly history!: ConsoleHistory;
 
     @inject(ConsoleSessionManager)
-    protected readonly sessionManager: ConsoleSessionManager;
+    protected readonly sessionManager!: ConsoleSessionManager;
 
     @inject(MonacoEditorProvider)
-    protected readonly editorProvider: MonacoEditorProvider;
+    protected readonly editorProvider!: MonacoEditorProvider;
 
-    protected _input: MonacoEditor;
+    protected _input!: MonacoEditor;
 
     constructor() {
         super();

packages/core/src/browser/about-dialog.tsx

@@ -26,17 +26,16 @@ export const ABOUT_CONTENT_CLASS = 'theia-aboutDialog';
 export const ABOUT_EXTENSIONS_CLASS = 'theia-aboutExtensions';
 
 @injectable()
-export class AboutDialogProps extends DialogProps {
+export abstract class AboutDialogProps extends DialogProps {
 }
 
 @injectable()
 export class AboutDialog extends ReactDialog<void> {
-    protected applicationInfo: ApplicationInfo | undefined;
+    protected applicationInfo?: ApplicationInfo;
     protected extensionsInfos: ExtensionInfo[] = [];
-    protected readonly okButton: HTMLButtonElement;
 
     @inject(ApplicationServer)
-    protected readonly appServer: ApplicationServer;
+    protected readonly appServer!: ApplicationServer;
 
     constructor(
         @inject(AboutDialogProps) protected readonly props: AboutDialogProps