Fix right panel soft crashes due to missing room prop

res/css/structures/_GroupView.scss

@@ -18,6 +18,7 @@ limitations under the License.
     display: flex;
     flex-direction: column;
     overflow: hidden;
+    flex-grow: 1;
 }
 
 .mx_GroupView_error {

src/components/structures/MatrixChat.tsx

@@ -983,7 +983,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             this.viewWelcome();
             return;
         }
-        if (!this.state.currentGroupId && !this.state.currentRoomId) {
+        if (!this.state.currentGroupId && !this.state.currentRoomId && !this.state.currentUserId) {
             this.viewHome();
         }
     }

src/components/structures/RightPanel.tsx

@@ -92,10 +92,23 @@ export default class RightPanel extends React.Component<IProps, IState> {
     }
 
     public static getDerivedStateFromProps(props: IProps): Partial<IState> {
-        const currentCard = RightPanelStore.instance.currentCardForRoom(props.room.roomId);
+        let currentCard: IRightPanelCard;
+        if (props.room) {
+            currentCard = RightPanelStore.instance.currentCardForRoom(props.room.roomId);
+        }
+        if (props.groupId) {
+            currentCard = RightPanelStore.instance.currentGroup;
+        }
+
+        if (currentCard && !RightPanelStore.instance.isPhaseValid(currentCard.phase, !!props.room)) {
+            // XXX: We can probably get rid of this workaround once GroupView is dead, it's unmounting happens weirdly
+            // late causing the app to soft-crash due to lack of a room object being passed to a RightPanel
+            return null; // skip this update, we're about to be unmounted and don't have the appropriate props
+        }
+
         return {
-            cardState: currentCard.state,
-            phase: currentCard.phase,
+            cardState: currentCard?.state,
+            phase: currentCard?.phase,
         };
     }
 
@@ -116,11 +129,7 @@ export default class RightPanel extends React.Component<IProps, IState> {
     };
 
     private onRightPanelStoreUpdate = () => {
-        const currentCard = RightPanelStore.instance.currentCardForRoom(this.props.room.roomId);
-        this.setState({
-            cardState: currentCard.state,
-            phase: currentCard.phase,
-        });
+        this.setState({ ...RightPanel.getDerivedStateFromProps(this.props) as IState });
     };
 
     private onClose = () => {
@@ -137,7 +146,7 @@ export default class RightPanel extends React.Component<IProps, IState> {
             });
         } else if (
             this.state.phase === RightPanelPhases.EncryptionPanel &&
-            this.state.cardState.verificationRequest && this.state.cardState.verificationRequest.pending
+            this.state.cardState.verificationRequest?.pending
         ) {
             // When the user clicks close on the encryption panel cancel the pending request first if any
             this.state.cardState.verificationRequest.cancel();
@@ -152,7 +161,7 @@ export default class RightPanel extends React.Component<IProps, IState> {
 
     public render(): JSX.Element {
         let card = <div />;
-        const roomId = this.props.room ? this.props.room.roomId : undefined;
+        const roomId = this.props.room?.roomId;
         const phase = this.props.overwriteCard?.phase ?? this.state.phase;
         const cardState = this.props.overwriteCard?.state ?? this.state.cardState;
         switch (phase) {

src/components/structures/ThreadView.tsx

@@ -106,7 +106,7 @@ export default class ThreadView extends React.Component<IProps, IState> {
 
     public componentWillUnmount(): void {
         this.teardownThread();
-        dis.unregister(this.dispatcherRef);
+        if (this.dispatcherRef) dis.unregister(this.dispatcherRef);
         const room = MatrixClientPeg.get().getRoom(this.props.mxEvent.getRoomId());
         room.removeListener(ThreadEvent.New, this.onNewThread);
         SettingsStore.unwatchSetting(this.layoutWatcherRef);

src/stores/right-panel/RightPanelStore.ts

@@ -156,7 +156,7 @@ export default class RightPanelStore extends ReadyWatchingStore {
         const cardState = redirect?.state ?? (Object.keys(card.state ?? {}).length === 0 ? null : card.state);
 
         // Checks for wrong SetRightPanelPhase requests
-        if (!this.isPhaseActionValid(targetPhase)) return;
+        if (!this.isPhaseValid(targetPhase)) return;
 
         if ((targetPhase === this.currentCardForRoom(rId)?.phase && !!cardState)) {
             // Update state: set right panel with a new state but keep the phase (dont know it this is ever needed...)
@@ -195,16 +195,16 @@ export default class RightPanelStore extends ReadyWatchingStore {
         const pState = redirect?.state ?? (Object.keys(card.state ?? {}).length === 0 ? null : card.state);
 
         // Checks for wrong SetRightPanelPhase requests
-        if (!this.isPhaseActionValid(targetPhase)) return;
+        if (!this.isPhaseValid(targetPhase)) return;
 
-        let roomCache = this.byRoom[rId];
+        const roomCache = this.byRoom[rId];
         if (!!roomCache) {
             // append new phase
             roomCache.history.push({ state: pState, phase: targetPhase });
             roomCache.isOpen = allowClose ? roomCache.isOpen : true;
         } else {
             // setup room panel cache with the new card
-            roomCache = {
+            this.byRoom[rId] = {
                 history: [{ phase: targetPhase, state: pState ?? {} }],
                 // if there was no right panel store object the the panel was closed -> keep it closed, except if allowClose==false
                 isOpen: !allowClose,
@@ -345,18 +345,18 @@ export default class RightPanelStore extends ReadyWatchingStore {
         return null;
     }
 
-    private isPhaseActionValid(targetPhase) {
+    public isPhaseValid(targetPhase: RightPanelPhases, isViewingRoom = this.isViewingRoom): boolean {
         if (!RightPanelPhases[targetPhase]) {
             logger.warn(`Tried to switch right panel to unknown phase: ${targetPhase}`);
             return false;
         }
-        if (GROUP_PHASES.includes(targetPhase) && this.isViewingRoom) {
+        if (GROUP_PHASES.includes(targetPhase) && isViewingRoom) {
             logger.warn(
                 `Tried to switch right panel to a group phase: ${targetPhase}, ` +
                 `but we are currently not viewing a group`,
             );
             return false;
-        } else if (!GROUP_PHASES.includes(targetPhase) && !this.isViewingRoom) {
+        } else if (!GROUP_PHASES.includes(targetPhase) && !isViewingRoom) {
             logger.warn(
                 `Tried to switch right panel to a room phase: ${targetPhase}, ` +
                 `but we are currently not viewing a room`,

src/stores/right-panel/RightPanelStorePhases.ts

@@ -56,23 +56,3 @@ export function backLabelForPhase(phase: RightPanelPhases) {
     }
     return null;
 }
-
-// These are the phases that are safe to persist (the ones that don't require additional
-// arguments).
-export const RIGHT_PANEL_PHASES_NO_ARGS = [
-    RightPanelPhases.RoomSummary,
-    RightPanelPhases.NotificationPanel,
-    RightPanelPhases.PinnedMessages,
-    RightPanelPhases.FilePanel,
-    RightPanelPhases.RoomMemberList,
-    RightPanelPhases.GroupMemberList,
-    RightPanelPhases.GroupRoomList,
-    RightPanelPhases.Timeline,
-];
-
-// Subset of phases visible in the Space View
-export const RIGHT_PANEL_SPACE_PHASES = [
-    RightPanelPhases.SpaceMemberList,
-    RightPanelPhases.Space3pidMemberInfo,
-    RightPanelPhases.SpaceMemberInfo,
-];