Bug 515515: For clients, mid-air collision results when user's timezone…

process_bug.cgi

@@ -153,9 +153,11 @@ print $cgi->header() unless Bugzilla->usage_mode == USAGE_MODE_EMAIL;
 
 # Check for a mid-air collision. Currently this only works when updating
 # an individual bug.
-if (defined $cgi->param('delta_ts')
-    && $cgi->param('delta_ts') ne $first_bug->delta_ts)
+if (defined $cgi->param('delta_ts'))
 {
+    my $delta_ts_z = datetime_from($cgi->param('delta_ts'));
+    my $first_delta_tz_z =  datetime_from($first_bug->delta_ts);
+    if ($first_delta_tz_z ne $delta_ts_z) {
         ($vars->{'operations'}) =
             Bugzilla::Bug::GetBugActivity($first_bug->id, undef,
                                           scalar $cgi->param('delta_ts'));
@@ -170,13 +172,14 @@ if (defined $cgi->param('delta_ts')
         # regardless of the user's personal preference.
         $vars->{'comments'} = $first_bug->comments({ order => "oldest_to_newest" });
         $vars->{'bug'} = $first_bug;
+
         # The token contains the old delta_ts. We need a new one.
         $cgi->param('token', issue_hash_token([$first_bug->id, $first_bug->delta_ts]));
-    
         # Warn the user about the mid-air collision and ask them what to do.
         $template->process("bug/process/midair.html.tmpl", $vars)
           || ThrowTemplateError($template->error());
         exit;
+    }
 }
 
 # We couldn't do this check earlier as we first had to validate bug IDs