[Bug] - App Crash on 'fetchMessagesByUIDOperationWithFolder:requestKind:uids:

[karam28]

Summary
I'm utilizing MailCore2 via CocoaPods. After copying the Objective-C code, my application crashes upon running. The crash is associated with a deprecated method mentioned in the warning from Xcode: 'fetchMessagesByUIDOperationWithFolder:requestKind:uids:'.

Platform(s)

<iOS>

Happens on Mail Server

<Yahoo>

Piece of code

    MCOIMAPSession *session = [[MCOIMAPSession alloc] init];
    [session setHostname:@"imap.mail.yahoo.com"];
    [session setPort:993];
    [session setUsername:@"xxx@yahoo.com"];
    [session setPassword:@"xxxx"];
    [session setConnectionType:MCOConnectionTypeTLS];

    MCOIMAPMessagesRequestKind requestKind = MCOIMAPMessagesRequestKindHeaders;
    NSString *folder = @"INBOX";
    MCOIndexSet *uids = [MCOIndexSet indexSetWithRange:MCORangeMake(1, UINT64_MAX)];

    MCOIMAPFetchMessagesOperation *fetchOperation = [session fetchMessagesByUIDOperationWithFolder:folder requestKind:requestKind uids:uids];

    [fetchOperation start:^(NSError * error, NSArray * fetchedMessages, MCOIndexSet * vanishedMessages) {
        //We've finished downloading the messages!

        //Let's check if there was an error:
        if(error) {
            NSLog(@"Error downloading message headers:%@", error);
        }

        //And, let's print out the messages...
        NSLog(@"The post man delivereth:%@", fetchedMessages);
    }];

Actual outcome
it should not crash. Please provide the updated method and update that in your documentation also.

Connection Logs

**Expected outcome**

**Link to sample code on GitHub reproducing the issue (a full Xcode project):**

[karam28]

I find the updated method I think but it's crashing and no reason mention. here is the crash Thread 5: EXC_BREAKPOINT (code=1, subcode=0x20fc0f374)

MCOIMAPSession *session = [[MCOIMAPSession alloc] init];
    session.hostname = @"imap.mail.yahoo.com";
    session.port = 993;
    session.username = @"karamjeetsinghbuttar@yahoo.com";
    session.password = @"ybykuvrpfxqswxqo ";
    session.connectionType = MCOConnectionTypeTLS;

    MCOIndexSet *uidSet = [MCOIndexSet indexSetWithRange:MCORangeMake(1,UINT64_MAX)];
  MCOIMAPFetchMessagesOperation * op = [session fetchMessagesOperationWithFolder:@"INBOX"
                                                                       requestKind:MCOIMAPMessagesRequestKindHeaders | MCOIMAPMessagesRequestKindStructure
                                                                              uids:uidSet];
    [op start:^(NSError * error, NSArray * messages, MCOIndexSet * vanishedMessages) {
       for(MCOIMAPMessage * msg in messages) {
         NSLog(@" mails-- %lu: %@", [msg uid], [msg header]);
       }
    }];

[Be-Maps]

this works for me :
extension MCOIMAPFetchMessagesOperation {

func fetchMessages() async throws -> [Any] {
    typealias PostContinuation = CheckedContinuation <[Any], Error>
    return try await withCheckedThrowingContinuation { [weak self] (continuation:PostContinuation) in
        guard let strongSelf = self else {
            logd("strongSelf Error downloading message UIDs")
            let mHeaders:[Any] = []
            continuation.resume(returning: mHeaders)
            return
        }
        
        strongSelf.start { (error: Error?, headers: [Any]?, indexSet: MCOIndexSet?) -> Void in
            if let error = error {
                logd("Error downloading message UIDs: \(error)")
                let mHeaders:[Any] = []
                continuation.resume(returning: mHeaders)
            } else {
                logd("Successful IMAP messages headers download")
                var mHeaders:[Any] = []
                if (headers != nil) {mHeaders = headers!}
                continuation.resume(returning: mHeaders)
            }
        }
    }
}

}

// ---------- and later:

    //Creating properties
    do {
        let session =  MCOIMAPSession()
        
        if (config.getIMAPSSL().equals("SSL")){
            session.hostname = config.getIMAPServer()
            session.username = config.getUserName()
            session.password = config.getPassword()
            session.port = UInt32.parseUInt32(config.getIMAPport())
            session.allowsFolderConcurrentAccessEnabled = true
            session.connectionType              = MCOConnectionType.TLS
            session.authType                    = MCOAuthType.saslLogin
            session.isCheckCertificateEnabled   = false
            session.isVoIPEnabled               = false
            session.maximumConnections          = 2
            session.timeout                     = App.connectionTimeout
        } else {
            session.hostname = config.getIMAPServer()
            session.username = config.getUserName()
            session.password = config.getPassword()
            session.port = UInt32.parseUInt32(config.getIMAPport())
            session.allowsFolderConcurrentAccessEnabled = true
            session.connectionType              = MCOConnectionType.startTLS
            session.authType                    = MCOAuthType.saslPlain
            session.isCheckCertificateEnabled   = false
            session.isVoIPEnabled               = false
            session.maximumConnections          = 2
            session.timeout                     = App.connectionTimeout
        }

        Log.d(TAG, "MoveAndCheck_ServerAndDeviceRegistrationEmails")
        var folderInbox:MCOIMAPFolderInfo = MCOIMAPFolderInfo()
        if let folderInfoOperation = session.folderInfoOperation("INBOX") {
            folderInbox = try await folderInfoOperation.start()
            logd("Successful IMAP folderInfoOperation")
        }

        let msgCount = folderInbox.messageCount
        if (msgCount<1) {
            Log.d(TAG, "MoveToServers: No messages to move")
            mResponse = "Move OK"
            return mResponse
        }

        let maxUID = folderInbox.uidNext
        var minUID:UInt32 = 0
        if (maxUID>200) {minUID = maxUID - 200}
        else {minUID = 1}
        
        let uids = MCOIndexSet(range: MCORange(location: UInt64(minUID), length: 201))
        
        var mMessages:[MCOIMAPMessage]? = []
        let requestKind: MCOIMAPMessagesRequestKind = [.headers, .headerSubject, .flags]
        
        if let fetchMessagesOperation = session.fetchMessagesOperation(withFolder: "INBOX", requestKind: requestKind , uids: uids) {
            let anyMessages = try await fetchMessagesOperation.fetchMessages()
            if (anyMessages.isEmpty) {
                mResponse = "Move OK"
                return mResponse
            } else {
                logd("Successful IMAP messages headers download")
                mMessages = anyMessages as? [MCOIMAPMessage]
            }
        }