[Python-Dev] Decimal <-> float comparisons in py3k.

[Terry Reedy]

On 3/20/2010 7:06 AM, Mark Dickinson wrote:

>> Will this change the result of hashing a long? I know that both gmpy
>> and SAGE use their own hash implementations for performance reasons. I
>> understand that CPython's hash function is an implementation detail,
>> but there are external modules that rely on the existing hash
>> behavior.
>
> Yes, it would change the hash of a long.
>
> What external modules are there that rely on existing hash behaviour?
> And exactly what behaviour do they rely on?

Depending on specifics of CPython's hash is a 'do at your own risk' 
enterprise, like CPython bytecode hacks.