Conform more of the codebase to strictNullChecks

src/MatrixClientPeg.ts

@@ -71,7 +71,7 @@ export interface IMatrixClientPeg {
      *
      * @returns {string} The homeserver name, if present.
      */
-    getHomeserverName(): string | null;
+    getHomeserverName(): string;
 
     get(): MatrixClient | null;
     safeGet(): MatrixClient;
@@ -358,10 +358,8 @@ class MatrixClientPegClass implements IMatrixClientPeg {
         };
     }
 
-    public getHomeserverName(): string | null {
-        if (!this.matrixClient) return null;
-
-        const matches = /^@[^:]+:(.+)$/.exec(this.matrixClient.getSafeUserId());
+    public getHomeserverName(): string {
+        const matches = /^@[^:]+:(.+)$/.exec(this.safeGet().getSafeUserId());
         if (matches === null || matches.length < 1) {
             throw new Error("Failed to derive homeserver name from user ID!");
         }

src/Searching.ts

@@ -234,9 +234,11 @@ async function localPagination(
 ): Promise<ISeshatSearchResults> {
     const eventIndex = EventIndexPeg.get();
 
-    const searchArgs = searchResult.seshatQuery;
+    if (!searchResult.seshatQuery) {
+        throw new Error("localSearchProcess must be called first");
+    }
 
-    const localResult = await eventIndex!.search(searchArgs);
+    const localResult = await eventIndex!.search(searchResult.seshatQuery);
     if (!localResult) {
         throw new Error("Local search pagination failed");
     }
@@ -408,7 +410,7 @@ function combineEvents(
 ): IResultRoomEvents {
     const response = {} as IResultRoomEvents;
 
-    const cachedEvents = previousSearchResult.cachedEvents;
+    const cachedEvents = previousSearchResult.cachedEvents ?? [];
     let oldestEventFrom = previousSearchResult.oldestEventFrom;
     response.highlights = previousSearchResult.highlights;
 
@@ -564,7 +566,7 @@ async function combinedPagination(
     // Fetch events from the server if we have a token for it and if it's the
     // local indexes turn or the local index has exhausted its results.
     if (searchResult.serverSideNextBatch && (oldestEventFrom === "local" || !searchArgs.next_batch)) {
-        const body = { body: searchResult._query, next_batch: searchResult.serverSideNextBatch };
+        const body = { body: searchResult._query!, next_batch: searchResult.serverSideNextBatch };
         serverSideResult = await client.search(body);
     }
 

src/components/structures/RoomView.tsx

@@ -1704,7 +1704,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
         } catch (error) {
             logger.error(`Failed to reject invite: ${error}`);
 
-            const msg = error.message ? error.message : JSON.stringify(error);
+            const msg = error instanceof Error ? error.message : JSON.stringify(error);
             Modal.createDialog(ErrorDialog, {
                 title: _t("Failed to reject invite"),
                 description: msg,

src/components/structures/ScrollPanel.tsx

@@ -700,7 +700,7 @@ export default class ScrollPanel extends React.Component<IProps> {
             const trackedNode = this.getTrackedNode();
             if (trackedNode) {
                 const newBottomOffset = this.topFromBottom(trackedNode);
-                const bottomDiff = newBottomOffset - scrollState.bottomOffset;
+                const bottomDiff = newBottomOffset - (scrollState.bottomOffset ?? 0);
                 this.bottomGrowth += bottomDiff;
                 scrollState.bottomOffset = newBottomOffset;
                 const newHeight = `${this.getListHeight()}px`;

src/components/structures/TimelinePanel.tsx

@@ -599,7 +599,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
 
         if (!this.timelineWindow?.canPaginate(dir)) {
             debuglog("can't", dir, "paginate any further");
-            this.setState<null>({ [canPaginateKey]: false });
+            this.setState({ [canPaginateKey]: false } as Pick<IState, typeof canPaginateKey>);
             return Promise.resolve(false);
         }
 
@@ -609,7 +609,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
         }
 
         debuglog("Initiating paginate; backwards:" + backwards);
-        this.setState<null>({ [paginatingKey]: true });
+        this.setState({ [paginatingKey]: true } as Pick<IState, typeof paginatingKey>);
 
         return this.onPaginationRequest(this.timelineWindow, dir, PAGINATE_SIZE).then(async (r) => {
             if (this.unmounted) {
@@ -2012,7 +2012,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
         return receiptStore?.getEventReadUpTo(myUserId, ignoreSynthesized) ?? null;
     }
 
-    private setReadMarker(eventId: string | null, eventTs: number, inhibitSetState = false): void {
+    private setReadMarker(eventId: string | null, eventTs?: number, inhibitSetState = false): void {
         const roomId = this.props.timelineSet.room?.roomId;
 
         // don't update the state (and cause a re-render) if there is
@@ -2023,7 +2023,11 @@ class TimelinePanel extends React.Component<IProps, IState> {
 
         // in order to later figure out if the read marker is
         // above or below the visible timeline, we stash the timestamp.
-        TimelinePanel.roomReadMarkerTsMap[roomId ?? ""] = eventTs;
+        if (eventTs !== undefined) {
+            TimelinePanel.roomReadMarkerTsMap[roomId ?? ""] = eventTs;
+        } else {
+            delete TimelinePanel.roomReadMarkerTsMap[roomId ?? ""];
+        }
 
         if (inhibitSetState) {
             return;

src/components/views/messages/MjolnirBody.tsx

@@ -18,15 +18,15 @@ import React from "react";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 
 import { _t } from "../../../languageHandler";
-import AccessibleButton from "../elements/AccessibleButton";
+import AccessibleButton, { ButtonEvent } from "../elements/AccessibleButton";
 
 interface IProps {
     mxEvent: MatrixEvent;
     onMessageAllowed: () => void;
 }
 
 export default class MjolnirBody extends React.Component<IProps> {
-    private onAllowClick = (e: React.MouseEvent): void => {
+    private onAllowClick = (e: ButtonEvent): void => {
         e.preventDefault();
         e.stopPropagation();
 

src/components/views/rooms/RoomListHeader.tsx

@@ -171,7 +171,7 @@ const RoomListHeader: React.FC<IProps> = ({ onVisibilityChange }) => {
         contextMenu = (
             <ContextMenuComponent
                 {...contextMenuBelow(mainMenuHandle.current.getBoundingClientRect())}
-                space={activeSpace}
+                space={activeSpace!}
                 onFinished={closeMainMenu}
                 hideHeader={true}
             />

src/components/views/rooms/RoomPreviewBar.tsx

@@ -155,7 +155,7 @@ export default class RoomPreviewBar extends React.Component<IProps, IState> {
                 );
                 this.setState({ invitedEmailMxid: result.mxid });
             } catch (err) {
-                this.setState({ threePidFetchError: err });
+                this.setState({ threePidFetchError: err as MatrixError });
             }
             this.setState({ busy: false });
         }

src/stores/ModalWidgetStore.ts

@@ -70,11 +70,7 @@ export class ModalWidgetStore extends AsyncStoreWithClient<IState> {
                 widgetRoomId,
                 sourceWidgetId: sourceWidget.id,
                 onFinished: (success, data) => {
-                    if (!success) {
-                        this.closeModalWidget(sourceWidget, widgetRoomId, { "m.exited": true });
-                    } else {
-                        this.closeModalWidget(sourceWidget, widgetRoomId, data);
-                    }
+                    this.closeModalWidget(sourceWidget, widgetRoomId, success && data ? data : { "m.exited": true });
 
                     this.openSourceWidgetId = null;
                     this.openSourceWidgetRoomId = null;

src/stores/right-panel/RightPanelStore.ts

@@ -363,15 +363,15 @@ export default class RightPanelStore extends ReadyWatchingStore {
             const panel = this.byRoom[this.viewedRoomId];
             if (panel?.history) {
                 panel.history = panel.history.filter(
-                    (card) =>
+                    (card: IRightPanelCard) =>
                         card.phase != RightPanelPhases.RoomMemberInfo &&
                         card.phase != RightPanelPhases.Room3pidMemberInfo,
                 );
             }
         }
         // when we're switching to a room, clear out thread permalinks to not get you stuck in the middle of the thread
         // in order to fix https://github.com/matrix-org/matrix-react-sdk/pull/11011
-        if (this.currentCard?.phase === RightPanelPhases.ThreadView) {
+        if (this.currentCard?.phase === RightPanelPhases.ThreadView && this.currentCard.state) {
             this.currentCard.state.initialEvent = undefined;
             this.currentCard.state.isInitialEventHighlighted = undefined;
             this.currentCard.state.initialEventScrollIntoView = undefined;

src/utils/AutoDiscoveryUtils.tsx

@@ -261,7 +261,15 @@ export default class AutoDiscoveryUtils {
             throw new UserFriendlyError("Unexpected error resolving homeserver configuration");
         }
 
-        let delegatedAuthentication = undefined;
+        let delegatedAuthentication:
+            | {
+                  authorizationEndpoint: string;
+                  registrationEndpoint?: string;
+                  tokenEndpoint: string;
+                  account?: string;
+                  issuer: string;
+              }
+            | undefined;
         if (discoveryResult[M_AUTHENTICATION.stable!]?.state === AutoDiscovery.SUCCESS) {
             const { authorizationEndpoint, registrationEndpoint, tokenEndpoint, account, issuer } = discoveryResult[
                 M_AUTHENTICATION.stable!

src/utils/DecryptFile.ts

@@ -60,7 +60,7 @@ export async function decryptFile(file?: IEncryptedFile, info?: IMediaEventInfo)
         }
         responseData = await response.arrayBuffer();
     } catch (e) {
-        throw new DownloadError(e);
+        throw new DownloadError(e as Error);
     }
 
     try {
@@ -77,6 +77,6 @@ export async function decryptFile(file?: IEncryptedFile, info?: IMediaEventInfo)
 
         return new Blob([dataArray], { type: mimetype });
     } catch (e) {
-        throw new DecryptError(e);
+        throw new DecryptError(e as Error);
     }
 }

src/utils/StorageManager.ts

@@ -36,7 +36,7 @@ function log(msg: string): void {
     logger.log(`StorageManager: ${msg}`);
 }
 
-function error(msg: string, ...args: string[]): void {
+function error(msg: string, ...args: any[]): void {
     logger.error(`StorageManager: ${msg}`, ...args);
 }
 

src/utils/promise.ts

@@ -33,14 +33,14 @@ export async function retry<T, E extends Error>(
     num: number,
     predicate?: (e: E) => boolean,
 ): Promise<T> {
-    let lastErr!: E;
+    let lastErr!: any;
     for (let i = 0; i < num; i++) {
         try {
             const v = await fn();
             // If `await fn()` throws then we won't reach here
             return v;
         } catch (err) {
-            if (predicate && !predicate(err)) {
+            if (predicate && !predicate(err as E)) {
                 throw err;
             }
             lastErr = err;

test/utils/media/requestMediaPermissions-test.tsx

@@ -41,7 +41,7 @@ describe("requestMediaPermissions", () => {
     describe("when an audio and video device is available", () => {
         beforeEach(() => {
             mocked(navigator.mediaDevices.getUserMedia).mockImplementation(
-                async ({ audio, video }): Promise<MediaStream> => {
+                async ({ audio, video }: MediaStreamConstraints): Promise<MediaStream> => {
                     if (audio && video) return audioVideoStream;
                     return audioStream;
                 },
@@ -56,7 +56,7 @@ describe("requestMediaPermissions", () => {
     describe("when calling with video = false and an audio device is available", () => {
         beforeEach(() => {
             mocked(navigator.mediaDevices.getUserMedia).mockImplementation(
-                async ({ audio, video }): Promise<MediaStream> => {
+                async ({ audio, video }: MediaStreamConstraints): Promise<MediaStream> => {
                     if (audio && !video) return audioStream;
                     return audioVideoStream;
                 },
@@ -72,7 +72,7 @@ describe("requestMediaPermissions", () => {
         beforeEach(() => {
             error.name = "NotFoundError";
             mocked(navigator.mediaDevices.getUserMedia).mockImplementation(
-                async ({ audio, video }): Promise<MediaStream> => {
+                async ({ audio, video }: MediaStreamConstraints): Promise<MediaStream> => {
                     if (audio && video) throw error;
                     if (audio) return audioStream;
                     return audioVideoStream;
@@ -103,7 +103,7 @@ describe("requestMediaPermissions", () => {
     describe("when an Error is raised", () => {
         beforeEach(async () => {
             mocked(navigator.mediaDevices.getUserMedia).mockImplementation(
-                async ({ audio, video }): Promise<MediaStream> => {
+                async ({ audio, video }: MediaStreamConstraints): Promise<MediaStream> => {
                     if (audio && video) throw error;
                     return audioVideoStream;
                 },