#14471: Category refinement sometimes changes the hash of parents
--------------------------------+-------------------------------------------
Reporter: vbraun | Owner: rlm
Type: defect | Status: needs_work
Priority: critical | Milestone: sage-5.11
Component: memleak | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers: Simon King
Authors: Volker Braun | Merged in:
Dependencies: | Stopgaps:
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Changes (by SimonKing):
* status: needs_review => needs_work
Comment:
There is no regression in startup time. However, I did not succeed to get
the warning when changing the hash. I tried:
{{{
Here is a test against :trac:`14471`. Refining the category will
issue
a warning, if this change affects the hash value (note that this
will
only be seen in doctest mode)::
sage: class MyParent(Parent):
....: def __hash__(self):
....: return hash(type(self))
....:
sage: a = MyParent(category=Rings())
sage: h = hash(a)
sage: a._refine_category_(Algebras(QQ))
hash of <class '__main__.MyParent_with_category'> changed in
Parent._refine_category_
sage: h == hash(a)
False
}}}
If I understand correctly, the check of refine category will by default be
done in doctests. But I get:
{{{
Failed example:
a._refine_category_(Algebras(QQ))
Expected:
hash of <class '__main__.MyParent_with_category'> changed in
Parent._refine_category_
Got:
<BLANKLINE>
}}}
So, what shall one do?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14471#comment:30>
Sage <http://www.sagemath.org>
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