Extend DER_object__cmp__() to handle None objects.

svn path=/rpkid/rpki/x509.py; revision=2578

1 files changed, 11 insertions, 2 deletions

diff --git a/rpkid/rpki/x509.py b/rpkid/rpki/x509.py
index 4cff5d05..540209d0 100644
--- a/rpkid/rpki/x509.py
+++ b/rpkid/rpki/x509.py
@@ -197,8 +197,17 @@ class DER_object(object):
     return self.pem_converter.to_PEM(self.get_DER())
 
   def __cmp__(self, other):
-    """Compare two DER-encoded objects."""
-    return cmp(self.get_DER(), other.get_DER())
+    """
+    Compare two DER-encoded objects.
+    """
+    if self is None and other is None:
+      return 0
+    elif self is None:
+      return -1
+    elif other is None:
+      return 1
+    else:
+      return cmp(self.get_DER(), other.get_DER())
 
   def hSKI(self):
     """