Issue1627

Hello,

I am working on a Jython script that calls a library of mine.
I have had a bug recently because a script test "foo ==  None" happened to call "foo.equals(null)".

The custom "equals" method I had written was not expecting to be tested against null values and then crashed.

I believe that Jython could avoid this. A test 'foo == None' could just be translated to the Java counterpart 'foo == null'. I do not believe that "equals" is supposed to expect a call with null values.

What do you think ?
Thanks,

Raphael

Not a bug.  CPython:

>>> class Foo (object):
...   def __eq__(self, that):
...     return True
...
>>> Foo () == None
True

You should use 'foo is None' instead.

Current behavior seems reasonable enough to me. From http://download.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#equals(java.lang.Object) :

"For any non-null reference value x, x.equals(null) should return false."

Given that the Java value of Jython's None is defined to be null, this is the correct behavior. Also, as doublep points out in msg5873, you normally want to use 'is None', this will be less surprising.