issue2550830: Fixed. Made LinkHTMLProperty a new-style class.

Author: bernhardreiter

CHANGES.txt

@@ -26,6 +26,9 @@ Features:
 
 Fixed:
 
+- issue2550830 An empty LinkHTMLProperty cannot be compared successfully. 
+  Improves the query editing page. Reported and fixed by R David Murray 
+  (Bernhard Reiter).
 - Fix Release-date of 1.5.0 in this file (thanks to Bernhard for
   discovery) (Ralf Schlatterbeck)
 - Pythons cgi form code can return a TypeError, we now guard for this

roundup/cgi/templating.py

@@ -1903,7 +1903,7 @@ def field(self, size=30, **kwargs):
         return self.input(name=self._formname, value=value, size=size,
                           **kwargs)
 
-class LinkHTMLProperty(HTMLProperty):
+class LinkHTMLProperty(HTMLProperty, object):
     """ Link HTMLProperty
         Include the above as well as being able to access the class
         information. Stringifying the object itself results in the value
@@ -1912,6 +1912,9 @@ class LinkHTMLProperty(HTMLProperty):
         property accessed (so item/assignedto/name would look up the user
         entry identified by the assignedto property on item, and then the
         name property of that user)
+
+        (Has been turned into a new-style class to enable comparisons
+        of values with None, see issue2550830.)
     """
     def __init__(self, *args, **kw):
         HTMLProperty.__init__(self, *args, **kw)