fix: Change power level without changing memory

The problem here is that we
have not created a deep copy
of the power level map. By using .copy() we create a
deep copy now.

lib/src/room.dart

@@ -1187,22 +1187,18 @@ class Room {
   /// Set the power level of the user with the [userID] to the value [power].
   /// Returns the event ID of the new state event. If there is no known
   /// power level event, there might something broken and this returns null.
-  Future<String> setPower(String userID, int power) async {
-    final powerMap = Map<String, Object?>.from(
-      getState(EventTypes.RoomPowerLevels)?.content ?? {},
-    );
-
-    final usersPowerMap = powerMap['users'] is Map<String, Object?>
-        ? powerMap['users'] as Map<String, Object?>
-        : (powerMap['users'] = <String, Object?>{});
+  Future<String> setPower(String userId, int power) async {
+    final powerLevelMapCopy =
+        getState(EventTypes.RoomPowerLevels)?.content.copy() ?? {};
 
-    usersPowerMap[userID] = power;
+    powerLevelMapCopy['users'] ??= <String, Object?>{};
+    powerLevelMapCopy.tryGetMap<String, Object?>('users')?[userId] = power;
 
     return await client.setRoomStateWithKey(
       id,
       EventTypes.RoomPowerLevels,
       '',
-      powerMap,
+      powerLevelMapCopy,
     );
   }
 

test/room_test.dart

@@ -786,6 +786,20 @@ void main() {
       await room.invite('Testname');
     });
 
+    test('setPower', () async {
+      final powerLevelMap =
+          room.getState(EventTypes.RoomPowerLevels, '')!.content.copy();
+
+      // Request to fake api does not update anything:
+      await room.setPower('@bob:fakeServer.notExisting', 100);
+
+      // Original power level map has not changed:
+      expect(
+        powerLevelMap,
+        room.getState(EventTypes.RoomPowerLevels, '')!.content.copy(),
+      );
+    });
+
     test('getParticipants', () async {
       var userList = room.getParticipants();
       expect(userList.length, 4);