Do not show "Forget room" button in Room View header for guest users

src/components/structures/RoomView.tsx

@@ -2459,6 +2459,10 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
                 viewingCall = true;
         }
 
+        const myMember = this.state.room!.getMember(this.context.client!.getSafeUserId());
+        const showForgetButton =
+            !this.context.client.isGuest() && (["leave", "ban"].includes(myMembership) || myMember?.isKicked());
+
         return (
             <RoomContext.Provider value={this.state}>
                 <main className={mainClasses} ref={this.roomView} onKeyDown={this.onReactKeyDown}>
@@ -2473,7 +2477,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
                             inRoom={myMembership === "join"}
                             onSearchClick={onSearchClick}
                             onInviteClick={onInviteClick}
-                            onForgetClick={myMembership === "leave" ? onForgetClick : null}
+                            onForgetClick={showForgetButton ? onForgetClick : null}
                             e2eStatus={this.state.e2eStatus}
                             onAppsClick={this.state.hasPinnedWidgets ? onAppsClick : null}
                             appsShown={this.state.showApps}

test/components/structures/RoomView-test.tsx

@@ -515,4 +515,33 @@ describe("RoomView", () => {
         await findByText("Are you sure you're at the right place?");
         expect(asFragment()).toMatchSnapshot();
     });
+
+    describe("Peeking", () => {
+        beforeEach(() => {
+            // Make room peekable
+            room.currentState.setStateEvents([
+                new MatrixEvent({
+                    type: "m.room.history_visibility",
+                    state_key: "",
+                    content: {
+                        history_visibility: "world_readable",
+                    },
+                    room_id: room.roomId,
+                }),
+            ]);
+        });
+
+        it("should show forget room button for non-guests", async () => {
+            mocked(cli.isGuest).mockReturnValue(false);
+            await mountRoomView();
+
+            expect(screen.getByLabelText("Forget room")).toBeInTheDocument();
+        });
+
+        it("should not show forget room button for guests", async () => {
+            mocked(cli.isGuest).mockReturnValue(true);
+            await mountRoomView();
+            expect(screen.queryByLabelText("Forget room")).not.toBeInTheDocument();
+        });
+    });
 });