Item11755: fix by completely disabling all entity processing

If we don't let HTML::TreeBuilder decode entities in the first place, we know
that all text nodes contain proper HTML entities and so we can skip
re-encoding things. This means we remove potentially fault-inducing steps of
processing which is a Good Thing™ and certainly beats the previous attempt at
fixing the problem in every way.

git-svn-id: http://svn.foswiki.org/branches/Release01x01@15832 0b4bb1d4-4e5a-0410-9cc4-b2b747904278

CompareRevisionsAddOn/lib/Foswiki/Contrib/CompareRevisionsAddOn/Compare.pm

@@ -329,6 +329,7 @@ sub _getTree {
 
     my $tree = new HTML::TreeBuilder;
     $tree->implicit_body_p_tag(1);
+    $tree->no_expand_entities(1);    # Item11755
     $tree->p_strict(1);
     $tree->parse($text);
     $tree->eof;
@@ -429,7 +430,8 @@ sub _findSubChanges {
 sub _elementHash {
 
     # Purpose: Stringify HTML ELement for comparison in Algorithm::Diff
-    my $text = ref( $_[0] ) eq $HTMLElement ? $_[0]->as_HTML('<>&') : "$_[0]";
+    # Item11755: prevent entity mangling
+    my $text = ref( $_[0] ) eq $HTMLElement ? $_[0]->as_HTML('') : "$_[0]";
 
     # Strip leading & trailing blanks in text and paragraphs
     $text =~ s/^\s*//;
@@ -521,8 +523,8 @@ sub _getTextWithClass {
     if ( ref($element) eq $HTMLElement ) {
         _addClass( $element, $class ) if $class;
 
-        # Don't let HTML::Entities touch high-bit bytes (Item11755)
-        return $element->as_HTML( '<>&', undef, {} );
+        # Item11755: prevent entity mangling
+        return $element->as_HTML( '', undef, {} );
     }
     elsif ($class) {
         return '<span class="' . $class . '">' . $element . '</span>';