GTCredentialProvider *credentialProvider = [GTCredentialProvider providerWithBlock:^GTCredential * _Nonnull(GTCredentialType type, NSString * _Nonnull URL, NSString * _Nonnull userName) 
{

    // the code newer called now

    NSError *error;
    GTCredential *credential;
    GPSSHKey *sshKey = [GPObjects fetchSSHKeyWithType:SSHKeyTypeGitHub];

    if (type & GTCredentialTypeSSHKey && sshKey != nil)
    {
        NSString *username = userName.length > 0 ? userName : hostingProvider.username;
        credential = [GTCredential credentialWithUserName:username publicKeyURL:sshKey.publicKeyStorageURL privateKeyURL:sshKey.privateKeyStorageURL passphrase:sshKey.passphrase error:&error];
    }
    else if (type & GTCredentialTypeUserPassPlaintext)
    {
        if (hostingProvider.username.length > 0 && hostingProvider.password.length > 0)
        {
            credential = [GTCredential credentialWithUserName:hostingProvider.username password:hostingProvider.password error:&error];
        }
        else if (sshKey != nil)
        {
            NSString *username = userName.length > 0 ? userName : hostingProvider.username;
            if (!username) {
                username = @"";
            }
            credential = [GTCredential credentialWithUserName:username publicKeyURL:sshKey.publicKeyStorageURL privateKeyURL:sshKey.privateKeyStorageURL passphrase:sshKey.passphrase error:&error];
        }
    }

    return credential;
}];

[options setObject:credentialProvider forKey:GTRepositoryCloneOptionsCredentialProvider];

[options setObject:@(YES) forKey:GTRepositoryCloneOptionsCloneLocal];

GTRepository *repository = [GTRepository cloneFromURL:gitURL toWorkingDirectory:localURL options:options error:&error transferProgressBlock:^(const git_transfer_progress * _Nonnull progress, BOOL * _Nonnull stop) {}];