Item7190: RSS feed broken, description tag contains byte 0

The description of VarUSERSIG contains \0 byte characters as seen here in this octal dump:

od -c WebRss.html
0000000   <   ?   x   m   l       v   e   r   s   i   o   n   =   "   1
0000020   .   0   "       e   n   c   o   d   i   n   g   =   "   i   s
0000040   o   -   8   8   5   9   -   1   "       ?   >   <   r   d   f
0000060   :   R   D   F       x   m   l   n   s   :   r   d   f   =   "
.....
0016740   /   i   t   e   m   >  \n   <   i   t   e   m       r   d   f
0016760   :   a   b   o   u   t   =   "   h   t   t   p   :   /   /   t
0017000   w   i   k   i   .   o   r   g   /   c   g   i   -   b   i   n
0017020   /   v   i   e   w   /   P   l   u   g   i   n   s   /   V   a
0017040   r   U   S   E   R   S   I   G   "   >  \n           <   t   i
0017060   t   l   e   >   V   a   r   U   S   E   R   S   I   G   <   /
0017100   t   i   t   l   e   >  \n           <   l   i   n   k   >   h
0017120   t   t   p   :   /   /   t   w   i   k   i   .   o   r   g   /
0017140   c   g   i   -   b   i   n   /   v   i   e   w   /   P   l   u
0017160   g   i   n   s   /   V   a   r   U   S   E   R   S   I   G   <
0017200   /   l   i   n   k   >  \n           <   d   e   s   c   r   i
0017220   p   t   i   o   n   >   #   V   a   r   U   S   E   R   S   I
0017240   G       U   S   E   R   S   I   G       s   h   o   w       u
0017260   s   e   r       s   i   g   n   a   t   u   r   e       w   i
0017300   t   h       p   r   o   f   i   l   e       p   i   c   t   u
0017320   r   e       i   c   o   n       S   y   n   t   a   x   :
0017340   %       n   o   p       U   S   E   R   S   I   G   {   W   i
0017360   k   i   N   a   m   e       o   r       %       n   o   p
0017400   U   S   E   R   S   I   G   {   W   i   k   i   N   a   m   e
0017420       Y   Y   Y   Y       M   M       D   D  \0       e   s   c
0017440      \0       1   }       .   .   .       (   l   a   s   t
0017460   c   h   a   n   g   e   d       b   y       P   e   t   e   r
0017500   T   h   o   e   n   y   )   <   /   d   e   s   c   r   i   p
0017520   t   i   o   n   >  \n           <   d   c   :   d   a   t   e
0017540   >   2   0   1   3   -   0   3   -   1   0   T   0   6   :   5
0017560   8   :   5   0   Z   <   /   d   c   :   d   a   t   e   >  \n
0017600           <   d   c   :   c   o   n   t   r   i   b   u   t   o

Source in VarUSERSIG:

%<nop>USERSIG{WikiName - YYYY-MM-DD}%

Actual output:

% nop USERSIG{WikiName YYYY MM DD\0 esc \0 1}

Expected output:

USERSIG{WikiName YYYY MM DD}

-- TWiki:Main/PeterThoeny - 2013-03-14

This is now fixed in TWiki::Render in svn trunk and 5.1 branch.

Negative enumeration of { } in %VAR{}% caused the cleanup of unbalanced brackets to fail in TWiki::Render, which introduced the null characters in RSS feeds.

Patch:

--- TWiki/Render.pm   (revision 25226)
+++ TWiki/Render.pm   (working copy)
@@ -1452,7 +1452,7 @@
     # Format e-mail to add spam padding (HTML tags removed later)
     $text =~ s/$STARTWW((mailto\:)?[a-zA-Z0-9-_.+]+@[a-zA-Z0-9-_.]+\.[a-zA-Z0-9-_]+)$ENDWW/_mailLink( $this, $1 )/gem;
     $text =~ s/<!--.*?-->//gs;          # remove all HTML comments
-    $text =~ s|<nop[ />]*>|$nopToken|g; # escape <nop>
+    $text =~ s|<nop[ /]*>|$nopToken|g;  # escape <nop>
     $text =~ s/<[^>]*>//g;              # remove all HTML tags
     $text =~ s/\&[a-z]+;/ /g;           # remove entities
     if( $opts =~ /nohead/ ) {
@@ -1493,7 +1493,7 @@
     $result = "$escToken$$theLevelRef$theOpen";
   } else {
     $result = "$escToken$$theLevelRef$theClose";
-    $$theLevelRef--;
+    $$theLevelRef-- if( $$theLevelRef > 0 );
   }
   return $result;
 }

-- TWiki:Main.PeterThoeny - 2013-03-15

At the same time I fixed the SpreadSheetPlugin that uses the same logic to enumerate the function brackets. They are now guarded to never be negative.

-- TWiki:Main.PeterThoeny - 2013-03-15