ftp_rmdir(): Remove directory operation failed.

[didax]

Whenever you need to update a plugin, this error is triggered:

Warning: ftp_rmdir(): Remove directory operation failed. in /wp-admin/includes/class-wp-filesystem-ftpext.php on line 381

when

define('FS_METHOD', 'ftpext');

is defined inside wp_config.php.

In this situation, the error seems to be caused by the deleting attemp of .maintenance file.
In this scenario the delete method of the class-wp-filesystem-ftpext.php is called with $recursive = false.
So, when .maintenance file not exists the condition on line 377 of class-wp-filesystem-ftpext.php is not executed and the next condition on line 380 is reached.
ftp_rmdir returns (rightly) a fault.

[anubisthejackle]

Something like the attached patch should do the trick: Verify the directory exists before attempting to run the delete on it.

[didax]

Yes, that's fine.

I think that the check can be placed before (outside the conditional statement) and simply return true because the file/dir was deleted.

Replying to anubisthejackle:

Something like the attached patch should do the trick: Verify the directory exists before attempting to run the delete on it.

[didax]

This is my solution...

if ( empty( $file ) ) {
    return false;
}
if ( ! $this->exists( $file ) ) {
    return true;
}
if ( 'f' == $type || $this->is_file( $file ) ) {
    return ftp_delete( $this->link, $file );
}
if ( ! $recursive ) {
    // ...
    // ...