Description:
------------
Despite documentation[1] explicitly stating that "If the value returned from the handler is FALSE (which it will be if no value is returned), the XML parser will stop parsing and xml_get_error_code() will return XML_ERROR_EXTERNAL_ENTITY_HANDLING.", the output of the attached test script will always be "No error".

phpinfo()
PHP Version => 5.6.18

xml

XML Support => active
XML Namespace Support => active
libxml2 Version => 2.9.3

[1]http://php.net/xml_set_external_entity_ref_handler

Test script:
---------------
<?php
$parser = xml_parser_create_ns('UTF-8');
xml_set_external_entity_ref_handler($parser, function($self, $names, $base, $system_id, $public_id)
  {
    print "@{$names}: '{$system_id}' {$public_id}\n";
    /* Ref: http://php.net/xml_set_external_entity_ref_handler
      If the value returned from the handler is FALSE (which it will be if no
      value is returned), the XML parser will stop parsing and
      xml_get_error_code() will return XML_ERROR_EXTERNAL_ENTITY_HANDLING.
    */
    return false;
  }
);

xml_parse($parser, '<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE p [
  <!ENTITY pic PUBLIC "image.gif" "http://example.org/image.gif">
]>
<p>&pic;</p>');

print xml_error_string(xml_get_error_code($parser)) . "\n";
?>