fix: add check for groupchats with only 1 member

Author: freekvandeven

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Change the ChatTranslations constructor to require all translations or use the ChatTranslations.empty constructor if you don't want to specify all translations
 - Remove the Divider between the users on the new chat screen
 - Add option to set a custom padding around the list of chats
+- Fix nullpointer when firstWhere returns null because there is only 1 person in a groupchat
 
 ## 1.4.3
 

packages/flutter_chat_firebase/lib/service/firebase_chat_overview_service.dart

@@ -91,11 +91,15 @@ class FirebaseChatOverviewService implements ChatOverviewService {
               var chat = element.doc.data();
               if (chat == null) return;
 
-              var otherUser = await _userService.getUser(
-                chat.users.firstWhere(
-                  (element) => element != currentUser?.id,
-                ),
-              );
+              var otherUser = chat.users.any(
+                (element) => element != currentUser?.id,
+              )
+                  ? await _userService.getUser(
+                      chat.users.firstWhere(
+                        (element) => element != currentUser?.id,
+                      ),
+                    )
+                  : null;
 
               var unread =
                   await _addUnreadChatSubscription(chat.id!, currentUser!.id!);
@@ -144,18 +148,18 @@ class FirebaseChatOverviewService implements ChatOverviewService {
                   imageUrl: chat.imageUrl ?? '',
                   unreadMessages: unread,
                   users: users,
-                  lastMessage: chat.lastMessage != null
+                  lastMessage: chat.lastMessage != null && otherUser != null
                       ? chat.lastMessage!.imageUrl == null
                           ? ChatTextMessageModel(
-                              sender: otherUser!,
+                              sender: otherUser,
                               text: chat.lastMessage!.text!,
                               timestamp: DateTime.fromMillisecondsSinceEpoch(
                                 chat.lastMessage!.timestamp
                                     .millisecondsSinceEpoch,
                               ),
                             )
                           : ChatImageMessageModel(
-                              sender: otherUser!,
+                              sender: otherUser,
                               imageUrl: chat.lastMessage!.imageUrl!,
                               timestamp: DateTime.fromMillisecondsSinceEpoch(
                                 chat.lastMessage!.timestamp