When is this code block accessed? [aka search comments, by comment entry date]

[Matthew A. R. Sherian]

I am attemting to extend the query interface to allow searching on
comments made after a certain date. i.e. a row is added to longdescs on
2004-01-10 on a bug changed on 2003-12-17. I'd like to catch bugs that
have activity (in my environment cvs checkins). In my quest to ascertain a
method by which this may be achieved I have come accross the section

[% BLOCK a_comment %]
  [% IF count > 0 %]
    <br>
    <i>------- Additional Comment
      <a name="c[% count %]" href="#c[% count %]">#[% count %]</a> From <a
      href="mailto:[% comment.email FILTER html %]">[% comment.name FILTER
      html %]</a> [%+ comment.time %] -------
    </i>
  [% END %]

in bug/comments.html.tmpl.

I also have lines 525-530 of buglist.cgi:
    my @funcdefs =
<snip>
         "^long_?desc,changedafter" => sub {
             my $table = "longdescs_$chartid";
             push(@supptables, "longdescs $table"); push(@wherepart,
             "$table.bug_id = bugs.bug_id"); $term = "$table.bug_when > "
             . SqlQuote(SqlifyDate($v));
         },
</snip>

however it appears that funcdefs is just an abandoned data structure.

I also inserted a new row into fielddefs and had it's name column set to
longdescs.bug_when and then tried a drop_down OR search. This seems to
work but only for a small subset of bugs that have comments on or after a
date.

If anyone could point me in the right direction to get this kind of search
working through the user interface it would be most appreciated.