When $wgEnforceHtmlIds=false, add legacy anchors

This means that old links will still work in a lot of cases.  However,
if the legacy anchor is invalid XML, we omit it.  In particular, on
non-Latin wikis, practically all old section links (from external
sources or using external links) are likely to break, since the first
character of legacy anchors starting with a non-ASCII character will be
".", which is invalid in XML as well as in HTML4.

diff --git a/includes/Linker.php b/includes/Linker.php
index 3eddbcc..f116fb4 100644 (file)
--- a/includes/Linker.php
+++ b/includes/Linker.php
@@ -1515,11 +1515,21 @@ class Linker {
         * @param string $anchor  The anchor to give the headline (the bit after the #)
         * @param string $text    The text of the header
         * @param string $link    HTML to add for the section edit link
+        * @param mixed  $legacyAnchor A second, optional anchor to give for
+        *   backward compatibility (false to omit)
         *
         * @return string HTML headline
         */
-       public function makeHeadline( $level, $attribs, $anchor, $text, $link ) {
-               return "<a name=\"$anchor\" id=\"$anchor\"></a><h$level$attribs$link <span class=\"mw-headline\">$text</span></h$level>";
+       public function makeHeadline( $level, $attribs, $anchor, $text, $link, $legacyAnchor = false ) {
+               $ret = "<a name=\"$anchor\" id=\"$anchor\"></a>"
+                       . "<h$level$attribs"
+                       . $link
+                       . " <span class=\"mw-headline\">$text</span>"
+                       . "</h$level>";
+               if ( $legacyAnchor !== false ) {
+                       $ret = "<a name=\"$legacyAnchor\" id=\"$legacyAnchor\"></a>$ret";
+               }
+               return $ret;
        }
 
        /**

diff --git a/includes/parser/Parser.php b/includes/parser/Parser.php
index 11cbc11..e3ee5e7 100644 (file)
--- a/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@ -3617,14 +3617,60 @@ class Parser
 
                        # Save headline for section edit hint before it's escaped
                        $headlineHint = $safeHeadline;
-                       $safeHeadline = Sanitizer::escapeId( $safeHeadline,
-                               $wgEnforceHtmlIds ? 'noninitial' : 'xml' );
-                       # HTML names must be case-insensitively unique (bug 10721)
+
+                       if ( $wgEnforceHtmlIds ) {
+                               $legacyHeadline = false;
+                               $safeHeadline = Sanitizer::escapeId( $safeHeadline,
+                                       'noninitial' );
+                       } else {
+                               # For reverse compatibility, provide an id that's
+                               # HTML4-compatible, like we used to.
+                               #
+                               # It may be worth noting, academically, that it's possible for
+                               # the legacy anchor to conflict with a non-legacy headline
+                               # anchor on the page.  In this case likely the "correct" thing
+                               # would be to either drop the legacy anchors or make sure
+                               # they're numbered first.  However, this would require people
+                               # to type in section names like "abc_.D7.93.D7.90.D7.A4"
+                               # manually, so let's not bother worrying about it.
+                               $legacyHeadline = Sanitizer::escapeId( $safeHeadline,
+                                       'noninitial' );
+                               $safeHeadline = Sanitizer::escapeId( $safeHeadline, 'xml' );
+
+                               if ( $legacyHeadline == $safeHeadline ) {
+                                       # No reason to have both (in fact, we can't)
+                                       $legacyHeadline = false;
+                               } elseif ( $legacyHeadline != Sanitizer::escapeId(
+                               $legacyHeadline, 'xml' ) ) {
+                                       # The legacy id is invalid XML.  We used to allow this, but
+                                       # there's no reason to do so anymore.  Backward
+                                       # compatibility will fail slightly in this case, but it's
+                                       # no big deal.
+                                       $legacyHeadline = false;
+                               }
+                       }
+
+                       # HTML names must be case-insensitively unique (bug 10721).  FIXME:
+                       # Does this apply to Unicode characters?  Because we aren't
+                       # handling those here.
                        $arrayKey = strtolower( $safeHeadline );
+                       if ( $legacyHeadline === false ) {
+                               $legacyArrayKey = false;
+                       } else {
+                               $legacyArrayKey = strtolower( $legacyHeadline );
+                       }
 
                        # count how many in assoc. array so we can track dupes in anchors
-                       isset( $refers[$arrayKey] ) ? $refers[$arrayKey]++ : $refers[$arrayKey] = 1;
-                       $refcount[$headlineCount] = $refers[$arrayKey];
+                       if ( isset( $refers[$arrayKey] ) ) {
+                               $refers[$arrayKey]++;
+                       } else {
+                               $refers[$arrayKey] = 1;
+                       }
+                       if ( isset( $refers[$legacyArrayKey] ) ) {
+                               $refers[$legacyArrayKey]++;
+                       } else {
+                               $refers[$legacyArrayKey] = 1;
+                       }
 
                        # Don't number the heading if it is the only one (looks silly)
                        if( $doNumberHeadings && count( $matches[3] ) > 1) {
@@ -3634,8 +3680,12 @@ class Parser
 
                        # Create the anchor for linking from the TOC to the section
                        $anchor = $safeHeadline;
-                       if($refcount[$headlineCount] > 1 ) {
-                               $anchor .= '_' . $refcount[$headlineCount];
+                       $legacyAnchor = $legacyHeadline;
+                       if ( $refers[$arrayKey] > 1 ) {
+                               $anchor .= '_' . $refers[$arrayKey];
+                       }
+                       if ( $legacyHeadline !== false && $refers[$legacyArrayKey] > 1 ) {
+                               $legacyAnchor .= '_' . $refers[$legacyArrayKey];
                        }
                        if( $enoughToc && ( !isset($wgMaxTocLevel) || $toclevel<$wgMaxTocLevel ) ) {
                                $toc .= $sk->tocLine($anchor, $tocline, $numbering, $toclevel);
@@ -3653,7 +3703,9 @@ class Parser
                        } else {
                                $editlink = '';
                        }
-                       $head[$headlineCount] = $sk->makeHeadline( $level, $matches['attrib'][$headlineCount], $anchor, $headline, $editlink );
+                       $head[$headlineCount] = $sk->makeHeadline( $level,
+                               $matches['attrib'][$headlineCount], $anchor, $headline,
+                               $editlink, $legacyAnchor );
 
                        $headlineCount++;
                }