When running Py2.4, take advantage of new logging module feature that

gives less ugly/misleading exceptions in some cases.
Not part of the default build.

extensions/python/xpcom/server/policy.py

@@ -35,6 +35,7 @@
 #
 # ***** END LICENSE BLOCK *****
 
+import sys
 from xpcom import xpcom_consts, _xpcom, client, nsError, logger
 from xpcom import ServerException, COMException
 import xpcom
@@ -283,6 +284,7 @@ class DefaultPolicy:
             # considered 'normal' - however, we still write a debug log
             # record to help track these otherwise silent exceptions.
 
+            if sys.version_info < (2,4):
                 # Note that Python 2.3 does not allow an explicit exc_info tuple
                 # and passing 'True' will not work as there is no exception pending.
                 # Trick things!
@@ -292,13 +294,21 @@ class DefaultPolicy:
                     except:
                         logger.debug("'%s' raised COM Exception %s",
                                  func_name, exc_val, exc_info = 1)
+            else:
+                logger.debug("'%s' raised COM Exception %s",
+                             func_name, exc_val, exc_info=exc_info)
+
             return exc_val.errno
         # Unhandled exception - always print a warning and the traceback.
         # As above, trick the logging module to handle Python 2.3
+        if sys.version_info < (2,4):
             try:
                 raise exc_info[0], exc_info[1], exc_info[2]
             except:
                 logger.exception("Unhandled exception calling '%s'", func_name)
+        else:
+            logger.error("Unhandled exception calling '%s'", func_name,
+                         exc_info=exc_info)
         return nsError.NS_ERROR_FAILURE
 
     # Called whenever an unhandled Python exception is detected as a result