#9016: make morphisms hashable
---------------------------------+------------------------------------------
Reporter: burcin | Owner: AlexGhitza
Type: defect | Status: needs_review
Priority: major | Milestone: sage-5.6
Component: categories | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers: Robert Bradshaw, Travis
Scrimshaw
Authors: Burcin Erocal | Merged in:
Dependencies: | Stopgaps:
---------------------------------+------------------------------------------
Comment (by robertwb):
This is getting a bit off topic, but if you have pickling that depends on
hash values then it's already broken (e.g. 32-bit vs 64-bit). And, no,
hashes do not need to be consistent to pickle dictionaries. All that we
need is that hashes are consistent within a given Python session. (On that
note, the fix of http://bugs.python.org/issue13703 is to make hashes
completely unpredictable between sessions, which will break any hard-coded
hash we have that (transitively) depends on something that hashes a
string.)
<rant>
Aside from this, I've also been bitten several times from changing a hash
(to making it faster, e.g. not simply doing {{{hash(str(self))}}}) hand
having to change random values all over the library, as well as the
nuisance of having to find a 32-bit computer to test on to get the new
32-bit value (because the tests pass just fine for me), both of which
provide near zero actual value.
</rant>
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9016#comment:22>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
