I'd better suggest throw proper exception with given messages

I think this is not only relevant for the bind operation, but also for other operations e.g. query. For example I want to catch LDAP_NO_SUCH_OBJECT (error code 32). Currently I'd have to parse the message to do this. So I suggest to reopen this issue.

@dontub Would you will to submit a pull request for that?

I just had a deeper look at it. I'm currently thinking about an exception factory like this

final class ExceptionFactory
{
    public static function createLdapException($messageFormat, $connection)
    {
        $errorCode = ldap_errno($connection);
        $errorMsg = ldap_err2str($errorCode);
        $message = strtr($messageFormat, [
            '%errorCode%' => $errorCode,
            '%errorMsg%'  => $errorMsg,
        ]);

        return new LdapException($message, $errorCode);
    }
}

instead of adding a call to ldap_errno() everywhere.

I also found four places where an LdapException is thrown without a call of an LDAP operation:

• symfony/src/Symfony/Component/Ldap/Adapter/ExtLdap/Adapter.php

  Line 29 in 3498259

  throw new LdapException('The LDAP PHP extension is not enabled.');

• symfony/src/Symfony/Component/Ldap/Adapter/ExtLdap/ConnectionOptions.php

  Line 86 in 3498259

  throw new LdapException(sprintf('Unknown option "%s".', $name));

• symfony/src/Symfony/Component/Ldap/Adapter/ExtLdap/EntryManager.php

  Line 162 in 3498259

  throw new LdapException(sprintf('Entry "%s" malformed, could not parse RDN.', $entry->getDn()));

• symfony/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php

  Line 83 in 3498259

  throw new LdapException(sprintf('Could not search in scope "%s".', $this->options['scope']));

Is the last one necessary as the OptionsResolver would already prevent this?
Should the LdapException be limited to errors of real LDAP operations? If yes, what would be an appropriate replacement for the exceptions above? The class comment of LdapException (LdapException is thrown if php ldap module is not loaded.) needs to be updated in any case. (The same holds true for DriverNotFoundException which has exactly the same comment.)

WDYT?

In case of the exception factory: Should PHP type hints be used there?