Ticket #1674: trac-links.php

<?php
/*
Plugin Name: Trac Links
Plugin URI: https://wordpress.org/
Description: Link ticket and changeset numbers to core.trac.
Version: 1.0
Author: WordPress.org
Author URI: https://wordpress.org/
*/

add_filter( 'the_content', 'markup_wporg_links', 10, 1 );
add_filter( 'comment_text', 'markup_wporg_links', 10, 1 );

function markup_wporg_links( $content ) {
        $url = parse_url( home_url( '/' ) );
        $url = untrailingslashit( $url['host'] . $url['path'] );

        switch( $url ) {
                case 'make.wordpress.org/meta':
                case 'make.wordpress.org/community':
                        $trac = 'meta';
                        break;

                default:
                        $trac = 'core';
                        break;
        }

        $find = array(
                '/(\s|^|\()(#(\d{4,5}))(\b|$)/im', // core  trac ticket #1234-core in http://core.trac.wordpress.org/ticket/
                '/(\s|^|\()(r(\d{4,5}))(\b|$)/im', // core changeset r1234-core in http://core.trac.wordpress.org/changeset/1234
                '/(?<!\w)\[(\d{4,5})\](?!\w)/im', // core changeset [12345]
                '/(?<!\w)\[(\d{4,5})-(\d{4,5})\](?!\w)/im', // core log [12345-54321]
                '/(\s|^|\()(diff:@(\d{4,5}):(\d{4,5}))(\b|$)/im', // core diff diff-core:@20:30 https://core.trac.wordpress.org/changeset?new=30&old=20
        );

        $replace = array(
                '$1<a href="https://'. $trac .'.trac.wordpress.org/ticket/$3">$2</a>', // trac ticket
                '$1<a href="https://'. $trac .'.trac.wordpress.org/changeset/$3">$2</a>', // trac changeset
                '<a href="https://'. $trac .'.trac.wordpress.org/changeset/$1">$0</a>', // trac changeset
                '<a href="https://'. $trac .'.trac.wordpress.org/log/?revs=$1-$2">$0</a>', // trac log
                '$1<a href="https://'. $trac .'.trac.wordpress.org/changeset?new=$4&old=$3">$2</a>', // diff
        );

        preg_match_all('#[^>]+(?=<[^/]*[^a])|[^>]+$#', $content, $matches, PREG_SET_ORDER);

        foreach ( $matches as $val ) {
                $content = str_replace($val[0],preg_replace($find,$replace,$val[0]),$content);
        }

        return $content;
}