Conform more of the codebase to strictNullChecks (#10738)

src/components/views/messages/MessageActionBar.tsx

@@ -64,7 +64,7 @@ interface IOptionsButtonProps {
     // TODO: Types
     getTile: () => any | null;
     getReplyChain: () => ReplyChain | null;
-    permalinkCreator: RoomPermalinkCreator;
+    permalinkCreator?: RoomPermalinkCreator;
     onFocusChange: (menuDisplayed: boolean) => void;
     getRelationsForEvent?: GetRelationsForEvent;
 }
@@ -208,10 +208,11 @@ const ReplyInThreadButton: React.FC<IReplyInThreadButton> = ({ mxEvent }) => {
         e.preventDefault();
         e.stopPropagation();
 
-        if (mxEvent.getThread() && !mxEvent.isThreadRoot) {
+        const thread = mxEvent.getThread();
+        if (thread?.rootEvent && !mxEvent.isThreadRoot) {
             defaultDispatcher.dispatch<ShowThreadPayload>({
                 action: Action.ShowThread,
-                rootEvent: mxEvent.getThread()!.rootEvent,
+                rootEvent: thread.rootEvent,
                 initialEvent: mxEvent,
                 scroll_into_view: true,
                 highlighted: true,

src/components/views/rooms/EventTile.tsx

@@ -576,6 +576,12 @@ export class UnwrappedEventTile extends React.Component<EventTileProps, IState>
 
         const encryptionInfo = MatrixClientPeg.get().getEventEncryptionInfo(mxEvent);
         const senderId = mxEvent.getSender();
+        if (!senderId) {
+            // something definitely wrong is going on here
+            this.setState({ verified: E2EState.Warning });
+            return;
+        }
+
         const userTrust = MatrixClientPeg.get().checkUserTrust(senderId);
 
         if (encryptionInfo.mismatchedSender) {

src/components/views/spaces/SpacePublicShare.tsx

@@ -55,7 +55,7 @@ const SpacePublicShare: React.FC<IProps> = ({ space, onFinished }) => {
                 {_t("Share invite link")}
                 <span>{copiedText}</span>
             </AccessibleButton>
-            {space.canInvite(MatrixClientPeg.get()?.getUserId()) && shouldShowComponent(UIComponent.InviteUsers) ? (
+            {space.canInvite(MatrixClientPeg.get()?.getSafeUserId()) && shouldShowComponent(UIComponent.InviteUsers) ? (
                 <AccessibleButton
                     className="mx_SpacePublicShare_inviteButton"
                     onClick={() => {