$sanitizer->url allows invalid URLs

[FerdiAgrio]

When checking a bunch of URLs, I came past an odd example of an 'URL' which passed the $sanitizer->url() method. Basically I'm only checking a random word like 'processwire' with the extra option to disallow relative-URLs and the need of scheme 'http' or 'https'.
Example:
$sanitizer->url('processwire', array('allowRelative' => false,'allowSchemes' => array('http', 'https')));

I tried to narrow it down:
$scheme = parse_url($value, PHP_URL_SCHEME); if($scheme !== false && strlen($scheme)) {...}
which didn't pass (correct, returns null)

Further on it checks for incorrect $scheme:
if(!$scheme) {...}

and checks the option 'allowRelative':
if($options['allowRelative']) {...}

since the value is 'processwire' we move to the else which says:
// relative urls aren't allowed, so add the scheme/protocol and validate $value = $this->filterValidateURL("http://$value", $options);
...which somehow passes

It would be nice if somebody can clear this up for me. Thanks in advance.

[LostKobrakai]

This is the old legacy repo of processwire. See here about where to submit your issue:
#2051

[FerdiAgrio]

Damn bookmarks need updating! Tnx!
Although I won't post it - found a satisfying answer here