runfix: don't try to migrate 1:1 conversation with deleted user (#16820…

…) (#16825)

* runfix: don't try to migrate 1:1 conversation with deleted user

* docs: improve comments

* test: add scenario that covers deleted users

src/script/conversation/ConversationRepository.test.ts

@@ -268,6 +268,41 @@ describe('ConversationRepository', () => {
       const conversationEntity = await conversationRepository.init1to1Conversation(conversation, true);
       expect(conversationEntity).toEqual(conversation);
     });
+
+    it('returns a proteus conversation even if both users support mls but the user was deleted on backend', async () => {
+      const conversationRepository = testFactory.conversation_repository!;
+      const userRepository = testFactory.user_repository!;
+
+      const otherUserId = {id: 'f718410c-3833-479d-bd80-af03f38416', domain: 'test-domain'};
+      const otherUser = new User(otherUserId.id, otherUserId.domain);
+      otherUser.isDeleted = true;
+
+      otherUser.supportedProtocols([ConversationProtocol.PROTEUS, ConversationProtocol.MLS]);
+
+      userRepository['userState'].users.push(otherUser);
+
+      const selfUserId = {id: '109da9ca-a495-47a870-9ffbe924b2d1', domain: 'test-domain'};
+      const selfUser = new User(selfUserId.id, selfUserId.domain);
+      selfUser.supportedProtocols([ConversationProtocol.PROTEUS, ConversationProtocol.MLS]);
+      jest.spyOn(conversationRepository['userState'], 'self').mockReturnValueOnce(selfUser);
+
+      const proteus1to1Conversation = _generateConversation({
+        type: CONVERSATION_TYPE.ONE_TO_ONE,
+        protocol: ConversationProtocol.PROTEUS,
+      });
+
+      const connection = new ConnectionEntity();
+      proteus1to1Conversation.connection(connection);
+      connection.conversationId = proteus1to1Conversation.qualifiedId;
+      connection.userId = otherUserId;
+      otherUser.connection(connection);
+
+      jest.spyOn(conversationRepository['conversationService'], 'getMLS1to1Conversation');
+
+      const conversationEntity = await conversationRepository.init1to1Conversation(proteus1to1Conversation, true);
+      expect(conversationEntity).toEqual(proteus1to1Conversation);
+      expect(conversationRepository['conversationService'].getMLS1to1Conversation).not.toHaveBeenCalled();
+    });
   });
 
   describe('getInitialised1To1Conversation', () => {

src/script/conversation/ConversationRepository.ts

@@ -1865,10 +1865,24 @@ export class ConversationRepository {
       // If there's local mls conversation, we want to use it
       const localMLSConversation = this.conversationState.findMLS1to1Conversation(otherUserId);
 
-      // If both users support mls or mls conversation is already known, we use it
+      // If mls conversation is already known, we use it
       // we never go back to proteus conversation, even if one of the users do not support mls anymore
       // (e.g. due to the change of supported protocols in team configuration)
-      if (protocol === ConversationProtocol.MLS || localMLSConversation) {
+      if (localMLSConversation) {
+        return this.initMLS1to1Conversation(otherUserId, isMLSSupportedByTheOtherUser);
+      }
+
+      // If both users support mls, we will initialise mls 1:1 conversation (unless it's a proteus 1:1 conversation with a user that has been deleted)
+      if (protocol === ConversationProtocol.MLS) {
+        // If the other user is deleted on backend, just open a proteus conversation and do not try to migrate it to mls.
+        if (isProteusConversation(conversation)) {
+          const otherUser = await this.userRepository.getUserById(otherUserId);
+          if (otherUser.isDeleted) {
+            this.logger.warn(`User ${otherUserId.id} is deleted, opening proteus conversation`);
+            return conversation;
+          }
+        }
+
         return this.initMLS1to1Conversation(otherUserId, isMLSSupportedByTheOtherUser);
       }