fix(nav): collapse push-tap, tab and back-arrow navigations into the back stack via replace

src/app/components/BackRouteHandler.tsx

@@ -10,8 +10,11 @@ export function BackRouteHandler({ children }: BackRouteHandlerProps) {
   const location = useLocation();
 
   const goBack = useCallback(() => {
+    // Back arrow walks up the route tree to the section root — semantically
+    // a "go up", not a "push parent". Replacing keeps the back-stack from
+    // growing when the user repeatedly taps back on nested screens.
     const parent = getRouteSectionParent(location.pathname);
-    if (parent) navigate(parent);
+    if (parent) navigate(parent, { replace: true });
   }, [navigate, location.pathname]);
 
   return children(goBack);

src/app/features/call-status/IncomingCallStrip.tsx

@@ -45,7 +45,11 @@ export function IncomingCallStrip({ call, room }: IncomingCallStripProps) {
   const callKey = getIncomingCallKey(call.callId, call.roomId);
 
   const handleAnswer = () => {
-    navigate(getDirectRoomPath(getCanonicalAliasOrRoomId(mx, call.roomId)));
+    // Mirror the native CallStyle Answer path (usePushNotifications
+    // pushNotificationActionPerformed handler): in-app strip Answer is the
+    // same semantic action — switch to the call room — so it should not
+    // grow the back stack either.
+    navigate(getDirectRoomPath(getCanonicalAliasOrRoomId(mx, call.roomId)), { replace: true });
     switchOrStartDmCall(call.roomId)
       .then(() => {
         const evId = call.notifEvent.getId();

src/app/hooks/useAndroidBackButton.ts

@@ -11,9 +11,9 @@ const EXIT_CONFIRM_WINDOW_MS = 2000;
 /**
  * Maps the Android hardware back button to web-equivalent behavior, using
  * an app-level back stack instead of the WebView's native history. The
- * WebView's canGoBack includes redirects / replaces / tab-switch entries
+ * WebView's canGoBack counts redirects and `replace` calls as separate
- * that inflate its depth, which is why we maintain our own stack keyed
+ * entries, so we cannot trust its depth — keep our own stack keyed off
- * off react-router's useNavigationType.
+ * react-router's useNavigationType.
  *
  *   1. Overlay/modal open → dispatch Escape (closes folds Overlay via
  *      focus-trap-react's escapeDeactivates).
@@ -29,6 +29,11 @@ const EXIT_CONFIRM_WINDOW_MS = 2000;
  *      second press within EXIT_CONFIRM_WINDOW_MS to exit; first press
  *      shows a native Android toast. Any navigation between presses
  *      resets the window so the prompt can't leak across screens.
+ *
+ * Stack-bloat sources are addressed at the navigation site (push-tap and
+ * sidebar tabs use `replace`, useRoomNavigate auto-replaces same-pathname
+ * navs) — keeping this tracker free of dedup logic that would otherwise
+ * have to reconcile against phantom router-history entries.
  */
 export const useAndroidBackButton = (): void => {
   const navigate = useNavigate();

src/app/hooks/usePushNotifications.ts

@@ -298,11 +298,15 @@ export function usePushNotificationsLifecycle(): void {
       const detail = (ev as CustomEvent).detail as
         | { roomId?: string; isInvite?: boolean }
         | undefined;
+      // Push-tap navigations are "switch to this", not "stack on top of where
+      // I was". Without replace, N notifications from the same chat plus tab
+      // hops accumulate as N+ entries in our app back-stack (see
+      // useAndroidBackButton) — user presses back many times to exit one chat.
       if (detail?.isInvite) {
-        navigate(getInboxInvitesPath());
+        navigate(getInboxInvitesPath(), { replace: true });
         return;
       }
-      if (detail?.roomId) navigateRoom(detail.roomId);
+      if (detail?.roomId) navigateRoom(detail.roomId, undefined, { replace: true });
     };
     const onSubChange = () => {
       if (isPushEnabled()) register().catch(noop);
@@ -350,7 +354,7 @@ export function usePushNotificationsLifecycle(): void {
             // route; `getHomeRoomPath` resolves to a Home-tab placeholder for IDs
             // it doesn't have in its left-rail, hence the DM path here.
             if (data.call_action === 'answer' && data.room_id) {
-              navigate(getDirectRoomPath(data.room_id));
+              navigate(getDirectRoomPath(data.room_id), { replace: true });
               setPendingCallAction({
                 kind: 'answer',
                 roomId: data.room_id,
@@ -381,11 +385,11 @@ export function usePushNotificationsLifecycle(): void {
             // carry notif_event_id and this branch will route them to the DM
             // tab incorrectly — revisit together with the group-call pipeline.
             if (data.room_id && data.notif_event_id) {
-              navigate(getDirectRoomPath(data.room_id));
+              navigate(getDirectRoomPath(data.room_id), { replace: true });
               return;
             }
 
-            if (data.room_id) navigateRoom(data.room_id);
+            if (data.room_id) navigateRoom(data.room_id, undefined, { replace: true });
           }
         );
       })

src/app/hooks/useRoomNavigate.ts

@@ -1,5 +1,5 @@
-import { useCallback } from 'react';
+import { useCallback, useRef } from 'react';
-import { NavigateOptions, useNavigate } from 'react-router-dom';
+import { NavigateOptions, useLocation, useNavigate } from 'react-router-dom';
 import { useAtomValue } from 'jotai';
 import { getCanonicalAliasOrRoomId } from '../utils/matrix';
 import {
@@ -18,18 +18,51 @@ import { useSetting } from '../state/hooks/settings';
 
 export const useRoomNavigate = () => {
   const navigate = useNavigate();
+  const location = useLocation();
   const mx = useMatrixClient();
   const roomToParents = useAtomValue(roomToParentsAtom);
   const mDirects = useAtomValue(mDirectAtom);
   const spaceSelectedId = useSelectedSpace();
   const [developerTools] = useSetting(settingsAtom, 'developerTools');
 
+  // navigate(samePath) creates a fresh history entry in react-router-v6 even
+  // though the screen does not change — repeated taps on the same chat from
+  // search/inbox/notifications would inflate the back-stack tracked by
+  // useAndroidBackButton. Force replace when the target matches the current
+  // pathname so callers do not need to pass it everywhere.
+  //
+  // Pathname tracking has two sources:
+  //   1. useLocation → pathnameRef on every render, for consistency with the
+  //      router after it commits a navigation we did not initiate.
+  //   2. Optimistic write inside safeNavigate, so two calls in the same tick
+  //      (before React commits the first) collapse correctly: the second sees
+  //      the target the first just navigated to and forces replace.
+  // Without (2), two simultaneous navigateRoom(samePath) calls — e.g. two
+  // notifications dispatched back-to-back, or a double-clicked list item —
+  // both compare against the pre-navigation pathname and both PUSH. Without
+  // (1), an external navigate() between our calls would leave pathnameRef
+  // ahead of the actual route.
+  //
+  // The callback identity stays stable (deps = [navigate] only) so consumers
+  // that wrap navigateRoom in their own useCallback do not capture a stale
+  // closure on every route change.
+  const pathnameRef = useRef(location.pathname);
+  pathnameRef.current = location.pathname;
+  const safeNavigate = useCallback(
+    (target: string, opts?: NavigateOptions) => {
+      const finalOpts = pathnameRef.current === target ? { ...opts, replace: true } : opts;
+      navigate(target, finalOpts);
+      pathnameRef.current = target;
+    },
+    [navigate]
+  );
+
   const navigateSpace = useCallback(
     (roomId: string) => {
       const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, roomId);
-      navigate(getSpacePath(roomIdOrAlias));
+      safeNavigate(getSpacePath(roomIdOrAlias));
     },
-    [mx, navigate]
+    [mx, safeNavigate]
   );
 
   const navigateRoom = useCallback(
@@ -48,7 +81,7 @@ export const useRoomNavigate = () => {
 
         const pSpaceIdOrAlias = getCanonicalAliasOrRoomId(mx, parentSpace);
 
-        navigate(
+        safeNavigate(
           getSpaceRoomPath(pSpaceIdOrAlias, openSpaceTimeline ? roomId : roomIdOrAlias, eventId),
           opts
         );
@@ -56,13 +89,13 @@ export const useRoomNavigate = () => {
       }
 
       if (mDirects.has(roomId)) {
-        navigate(getDirectRoomPath(roomIdOrAlias, eventId), opts);
+        safeNavigate(getDirectRoomPath(roomIdOrAlias, eventId), opts);
         return;
       }
 
-      navigate(getHomeRoomPath(roomIdOrAlias, eventId), opts);
+      safeNavigate(getHomeRoomPath(roomIdOrAlias, eventId), opts);
     },
-    [mx, navigate, spaceSelectedId, roomToParents, mDirects, developerTools]
+    [mx, safeNavigate, spaceSelectedId, roomToParents, mDirects, developerTools]
   );
 
   return {

src/app/pages/client/sidebar/DirectTab.tsx

@@ -10,6 +10,7 @@ import { mDirectAtom } from '../../../state/mDirectList';
 import { allRoomsAtom } from '../../../state/room-list/roomList';
 import { roomToUnreadAtom } from '../../../state/room/roomToUnread';
 import { getDirectPath, joinPathComponent } from '../../pathUtils';
+import { isNativePlatform } from '../../../utils/capacitor';
 import { useRoomsUnread } from '../../../state/hooks/unread';
 import {
   SidebarAvatar,
@@ -77,13 +78,14 @@ export function DirectTab() {
   const directSelected = useDirectSelected();
 
   const handleDirectClick = () => {
+    const navOpts = { replace: isNativePlatform() };
     const activePath = navToActivePath.get('direct');
     if (activePath && screenSize !== ScreenSize.Mobile) {
-      navigate(joinPathComponent(activePath));
+      navigate(joinPathComponent(activePath), navOpts);
       return;
     }
 
-    navigate(getDirectPath());
+    navigate(getDirectPath(), navOpts);
   };
 
   const handleContextMenu: MouseEventHandler<HTMLButtonElement> = (evt) => {

src/app/pages/client/sidebar/ExploreTab.tsx

@@ -16,6 +16,7 @@ import { useMatrixClient } from '../../../hooks/useMatrixClient';
 import { getMxIdServer } from '../../../utils/matrix';
 import { ScreenSize, useScreenSizeContext } from '../../../hooks/useScreenSize';
 import { useNavToActivePathAtom } from '../../../state/hooks/navToActivePath';
+import { isNativePlatform } from '../../../utils/capacitor';
 
 export function ExploreTab() {
   const { t } = useTranslation();
@@ -28,28 +29,29 @@ export function ExploreTab() {
   const exploreSelected = useExploreSelected();
 
   const handleExploreClick = () => {
+    const navOpts = { replace: isNativePlatform() };
     if (screenSize === ScreenSize.Mobile) {
-      navigate(getExplorePath());
+      navigate(getExplorePath(), navOpts);
       return;
     }
 
     const activePath = navToActivePath.get('explore');
     if (activePath) {
-      navigate(joinPathComponent(activePath));
+      navigate(joinPathComponent(activePath), navOpts);
       return;
     }
 
     if (clientConfig.featuredCommunities?.openAsDefault) {
-      navigate(getExploreFeaturedPath());
+      navigate(getExploreFeaturedPath(), navOpts);
       return;
     }
     const userId = mx.getUserId();
     const userServer = userId ? getMxIdServer(userId) : undefined;
     if (userServer) {
-      navigate(getExploreServerPath(userServer));
+      navigate(getExploreServerPath(userServer), navOpts);
       return;
     }
-    navigate(getExplorePath());
+    navigate(getExplorePath(), navOpts);
   };
 
   return (

src/app/pages/client/sidebar/HomeTab.tsx

@@ -11,6 +11,7 @@ import { roomToParentsAtom } from '../../../state/room/roomToParents';
 import { allRoomsAtom } from '../../../state/room-list/roomList';
 import { roomToUnreadAtom } from '../../../state/room/roomToUnread';
 import { getHomePath, joinPathComponent } from '../../pathUtils';
+import { isNativePlatform } from '../../../utils/capacitor';
 import { useRoomsUnread } from '../../../state/hooks/unread';
 import {
   SidebarAvatar,
@@ -78,13 +79,19 @@ export function HomeTab() {
   const [menuAnchor, setMenuAnchor] = useState<RectCords>();
 
   const handleHomeClick = () => {
+    // On native, tab tap is "switch tab", not "stack on top" — replace keeps
+    // the app back-stack (see useAndroidBackButton) reflecting actual content
+    // navigation, not tab toggles. Same in Direct/Inbox/Explore/Space tabs.
+    // On web we keep PUSH so browser-back behaves the way desktop users
+    // expect: back undoes the tab switch.
+    const navOpts = { replace: isNativePlatform() };
     const activePath = navToActivePath.get('home');
     if (activePath && screenSize !== ScreenSize.Mobile) {
-      navigate(joinPathComponent(activePath));
+      navigate(joinPathComponent(activePath), navOpts);
       return;
     }
 
-    navigate(getHomePath());
+    navigate(getHomePath(), navOpts);
   };
 
   const handleContextMenu: MouseEventHandler<HTMLButtonElement> = (evt) => {

src/app/pages/client/sidebar/InboxTab.tsx

@@ -20,6 +20,7 @@ import { useInboxSelected } from '../../../hooks/router/useInbox';
 import { UnreadBadge } from '../../../components/unread-badge';
 import { ScreenSize, useScreenSizeContext } from '../../../hooks/useScreenSize';
 import { useNavToActivePathAtom } from '../../../state/hooks/navToActivePath';
+import { isNativePlatform } from '../../../utils/capacitor';
 
 export function InboxTab() {
   const { t } = useTranslation();
@@ -31,18 +32,19 @@ export function InboxTab() {
   const inviteCount = allInvites.length;
 
   const handleInboxClick = () => {
+    const navOpts = { replace: isNativePlatform() };
     if (screenSize === ScreenSize.Mobile) {
-      navigate(getInboxPath());
+      navigate(getInboxPath(), navOpts);
       return;
     }
     const activePath = navToActivePath.get('inbox');
     if (activePath) {
-      navigate(joinPathComponent(activePath));
+      navigate(joinPathComponent(activePath), navOpts);
       return;
     }
 
     const path = inviteCount > 0 ? getInboxInvitesPath() : getInboxNotificationsPath();
-    navigate(path);
+    navigate(path, navOpts);
   };
 
   return (

src/app/pages/client/sidebar/SpaceTabs.tsx

@@ -62,6 +62,7 @@ import { RoomUnreadProvider, RoomsUnreadProvider } from '../../../components/Roo
 import { useSelectedSpace } from '../../../hooks/router/useSelectedSpace';
 import { UnreadBadge } from '../../../components/unread-badge';
 import { getCanonicalAliasOrRoomId, isRoomAlias } from '../../../utils/matrix';
+import { isNativePlatform } from '../../../utils/capacitor';
 import { RoomAvatar } from '../../../components/room-avatar';
 import { nameInitials, randomStr } from '../../../utils/common';
 import {
@@ -760,18 +761,19 @@ export function SpaceTabs({ scrollRef }: SpaceTabsProps) {
     if (!targetSpaceId) return;
 
     const spacePath = getSpacePath(getCanonicalAliasOrRoomId(mx, targetSpaceId));
+    const navOpts = { replace: isNativePlatform() };
     if (screenSize === ScreenSize.Mobile) {
-      navigate(spacePath);
+      navigate(spacePath, navOpts);
       return;
     }
 
     const activePath = navToActivePath.get(targetSpaceId);
     if (activePath && activePath.pathname.startsWith(spacePath)) {
-      navigate(joinPathComponent(activePath));
+      navigate(joinPathComponent(activePath), navOpts);
       return;
     }
 
-    navigate(getSpaceLobbyPath(getCanonicalAliasOrRoomId(mx, targetSpaceId)));
+    navigate(getSpaceLobbyPath(getCanonicalAliasOrRoomId(mx, targetSpaceId)), navOpts);
   };
 
   const handleFolderToggle: MouseEventHandler<HTMLButtonElement> = (evt) => {