Hide the archived section (#12286)

* Hide the archived section

* Only add archived section if necessary

* Update e2e tests

src/components/views/rooms/RoomList.tsx

@@ -87,7 +87,10 @@ export const TAG_ORDER: TagID[] = [
     DefaultTagID.LowPriority,
     DefaultTagID.ServerNotice,
     DefaultTagID.Suggested,
-    DefaultTagID.Archived,
+    // DefaultTagID.Archived isn't here any more: we don't show it at all.
+    // The section still exists in the code as a place for rooms that we know
+    // about but aren't joined. At some point it could be removed entirely
+    // but we'd have to make sure that rooms you weren't in were hidden.
 ];
 const ALWAYS_VISIBLE_TAGS: TagID[] = [DefaultTagID.DM, DefaultTagID.Untagged];
 

src/stores/room-list/algorithms/Algorithm.ts

@@ -498,6 +498,8 @@ export class Algorithm extends EventEmitter {
             newTags[DefaultTagID.Invite].push(room);
         }
         for (const room of memberships[EffectiveMembership.Leave]) {
+            // We may not have had an archived section previously, so make sure its there.
+            if (newTags[DefaultTagID.Archived] === undefined) newTags[DefaultTagID.Archived] = [];
             newTags[DefaultTagID.Archived].push(room);
         }