Update for compatibility with v12 rooms (#30452)

* Update for compatibility with v12 rooms

Stop using powerLevelNorm and reading PL events manually.

To support https://github.com/matrix-org/matrix-js-sdk/pull/4937

* Add test for leave space dialog

* Don't compute stuff if we don't need it

* Use room.client

* Use getSafeUserId

* Remove client arg

* Use getJoinedMembers

and add doc

* Fix tests

* Fix more tests

* Fix other test

* Clarify comment

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

test/unit-tests/components/structures/MatrixChat-test.tsx

@@ -691,6 +691,8 @@ describe("<MatrixChat />", () => {
                     jest.spyOn(spaceRoom, "isSpaceRoom").mockReturnValue(true);
 
                     jest.spyOn(ReleaseAnnouncementStore.instance, "getReleaseAnnouncement").mockReturnValue(null);
+                    (room as any).client = mockClient;
+                    (spaceRoom as any).client = mockClient;
                 });
 
                 describe("forget_room", () => {
@@ -775,6 +777,22 @@ describe("<MatrixChat />", () => {
                                 ),
                             ).toBeInTheDocument();
                         });
+                        it("should warn when user is the last admin", async () => {
+                            jest.spyOn(room, "getJoinedMembers").mockReturnValue([
+                                { powerLevel: 100 } as unknown as MatrixJs.RoomMember,
+                                { powerLevel: 0 } as unknown as MatrixJs.RoomMember,
+                            ]);
+                            jest.spyOn(room, "getMember").mockReturnValue({
+                                powerLevel: 100,
+                            } as unknown as MatrixJs.RoomMember);
+                            dispatchAction();
+                            await screen.findByRole("dialog");
+                            expect(
+                                screen.getByText(
+                                    "You're the only administrator in this room. If you leave, nobody will be able to change room settings or take other important actions.",
+                                ),
+                            ).toBeInTheDocument();
+                        });
                         it("should do nothing on cancel", async () => {
                             dispatchAction();
                             const dialog = await screen.findByRole("dialog");

test/unit-tests/components/views/dialogs/LeaveSpaceDialog-test.tsx

@@ -0,0 +1,50 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import React from "react";
+import { render, screen } from "jest-matrix-react";
+import { MatrixEvent, type RoomMember } from "matrix-js-sdk/src/matrix";
+
+import LeaveSpaceDialog from "../../../../../src/components/views/dialogs/LeaveSpaceDialog";
+import { createTestClient, mkStubRoom } from "../../../../test-utils";
+
+describe("LeaveSpaceDialog", () => {
+    it("should warn about not being able to rejoin non-public space", () => {
+        const mockClient = createTestClient();
+        const mockSpace = mkStubRoom("myfakeroom", "myfakeroom", mockClient) as any;
+        jest.spyOn(mockSpace.currentState, "getStateEvents").mockReturnValue(
+            new MatrixEvent({
+                type: "m.room.join_rules",
+                content: {
+                    join_rule: "invite",
+                },
+            }),
+        );
+
+        render(<LeaveSpaceDialog space={mockSpace} onFinished={jest.fn()} />);
+
+        expect(screen.getByText(/You won't be able to rejoin unless you are re-invited/)).toBeInTheDocument();
+    });
+
+    it("should warn if user is the only admin", () => {
+        const mockClient = createTestClient();
+        const mockSpace = mkStubRoom("myfakeroom", "myfakeroom", mockClient) as any;
+        jest.spyOn(mockSpace, "getJoinedMembers").mockReturnValue([
+            { powerLevel: 100 } as unknown as RoomMember,
+            { powerLevel: 0 } as unknown as RoomMember,
+        ]);
+        jest.spyOn(mockSpace, "getMember").mockReturnValue({
+            powerLevel: 100,
+        } as unknown as RoomMember);
+
+        render(<LeaveSpaceDialog space={mockSpace} onFinished={jest.fn()} />);
+
+        expect(
+            screen.getByText(/You're the only admin of this space. Leaving it will mean no one has control over it./),
+        ).toBeInTheDocument();
+    });
+});