Undocumented dependency for regex parsing in IRI.php?

[jneubert]

The parse() function of IRI.php works fine for me on a Centos 6/PHP 5.3.3 installation. It fails however on Centos 5 (with rpm package php53/PHP 5.3.3 installed).

I could track it down to to following lines of code (first and last line added for demonstration):

    $iri = 'http://www.w3.org/2004/02/skos/core#hiddenLabel';

    // Parse IRI by using the regular expression as specified by
    // http://tools.ietf.org/html/rfc3986#appendix-B
    $regex = '|^((?P<scheme>[^:/?#]+):)?' .
                '((?P<doubleslash>//)(?P<authority>[^/?#]*))?(?P<path>[^?#]*)' .
                '((?<querydef>\?)(?P<query>[^#]*))?(#(?P<fragment>.*))?|';
    preg_match($regex, $iri, $match);

    print $match['scheme'] . "\n";

On Centos 6, "http" is printed.

On Centos 5, I get the message:

PHP Warning: preg_match(): Compilation failed: unrecognized character after (?< at offset 89 in [...]temp.php on line 9

without any other output.

Perhaps I'm missing some unknown dependency - help much appreciated.

Cheers, Joachim

[lanthaler]

Thanks for reporting this Joachim. You are right, there’s a dependency on the PCRE library. Apparently CentOS’s default repositories don’t have the latest version. Can you try to update it to at least 8.0 (perhaps using http://www.jasonlitka.com/yum-repository/). You can easily check the version of the PCRE library by running

php composer.phar show --platform

I’ve already updated composer.json to specifiy this dependency. Let me know if that solves the issue.

[jneubert]

Thanks for the hints, Markus. Unfortunately, after setting up the utterramblings repo, I could not install the pcre-8.x version from there - presumably the active yum-plugins (security, protectbase) prevent it. Circumventing this on my dev system would not help much, because the IT team responsible for the prod system for sure would not accept such a step. Since the regex worked in a prior JsonLD version, would it perhaps be possible to re-formulate it to a pcre-6.6 compatible version?

[lanthaler]

I would be happy to do so but don’t have the time right now to do it myself. Could you file a PR?

[osma]

I have a related problem. I'm also trying to deploy on CentOS 6 and Composer now complains that lib-pcre 8.0 is not available (CentOS 6 has lib-pcre 7.9).

As I understand, you already changed the code to be compatible with older pcre, but the dependency in composer.json is specified for >= 8.0. Could you please change composer.json to match the updated code? Maybe to lib-pcre >=6.6. Then Composer would be happy and not fail to install ml/iri 1.1.3.

At the moment I'm back to using ml/iri 1.1.2 because that works on CentOS 6.

Thanks, Osma

[lanthaler]

Good catch. I've updated composer.json to require lib-pcre >= 4.0 (which is the version that added support for named subpatterns using the Python syntax). Could you please confirm that this resolves the problem you are experiencing.

Thanks

[osma]

Thanks a lot, ml/iri 1.1.4 installs and works perfectly on CentOS 6 now!