Keep sidebar present when showing error "Unknown administration panel" error

[Ryan J Ollos]

When the path matches /admin but does not match any IAdminPanelProviders, we see:

It would be nice if we could keep the navigation sidebar visible when rendering the message.

[Ryan J Ollos]

I experimented with this a bit, but I think it's probably not worth implementing.

trac/admin/templates/admin.html

@@ -49 +49 @@
         </ul>
         # endfor
       </div>
+      # if error:
+      <div id="tabcontent">
+        <h2>${_("Error: Not Found")}</h2>
+        <div class="system-message">${error}</p>
+      </div>
+      # else:
       <div id="tabcontent">
         # block adminpanel
         # endblock adminpanel
         <br style="clear: right" />
       </div>
+      # endif
     </div>
     ${ super() }
     # endblock content

trac/admin/web_ui.py

@@ -88 +88 @@
                 panel_id = \
                     filter(lambda panel: panel[0] == cat_id, panels)[0][2]
             except IndexError:
-                raise HTTPNotFound(_("Unknown administration panel"))
+                cat_id = panel_id = None
 
         provider = providers.get((cat_id, panel_id))
-        if not provider:
-            raise HTTPNotFound(_("Unknown administration panel"))
-
-        resp = provider.render_admin_panel(req, cat_id, panel_id, path_info)
-        template, data = resp[:2]
+        if provider:
+            resp = provider.render_admin_panel(req, cat_id, panel_id, path_info)
+            data = resp[1]
+            data.update({'active_cat': cat_id, 'active_panel': panel_id})
+        else:
+            data = {'error': _("Unknown administration panel")}
+            resp = 'admin.html', data
 
         data.update({
-            'active_cat': cat_id, 'active_panel': panel_id,
             'panel_href': partial(req.href, 'admin', cat_id, panel_id),
             'panels': [{
                 'category': {'id': panel[0], 'label': panel[1]},