#13394: Write a WeakValueDictionary with safer key removal
-------------------------------------+-------------------------------------
Reporter: nbruin | Owner: rlm
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.13
Component: memleak | Resolution:
Keywords: | Merged in:
Authors: Simon King, Nils | Reviewers: Simon King
Bruin | Work issues:
Report Upstream: None of the above | Commit:
- read trac for reasoning. | 851cc9522dde332561101f1c84182a0a84b8eed4
Branch: | Stopgaps:
u/SimonKing/ticket/13394 |
Dependencies: |
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Comment (by SimonKing):
This version of your test (using a python wrapper for the cdef function)
needs 12.5 CPU-seconds on my laptop. I think that's fine for a long test.
{{{
def test_del_dictitem_by_exact_value(D, value, h):
"""
This function helps testing some cdef function used to delete
dictionary items.
INPUT:
- ``D`` -- a Python ``<dict>``.
- ``value`` -- an object that is value ``D``.
- ``h`` -- the hash of the key under which to find ``value`` in ``D``.
<Further doc to be added>
TESTS:
See :trac:`13394` for a discussion.
::
sage: from sage.misc.weak_dict import
test_del_dictitem_by_exact_value
sage: B=1000
sage: L=list(range(B))
sage: D1=dict()
sage: D2=dict()
sage: for i in range(100000): # optional: long
....: ki=L[floor(random()*B)]
....: vi=L[floor(random()*B)]
....: D1[ki]=vi
....: D2[ki]=vi
....: ko=L[floor(random()*B)]
....: if ko in D1:
....: vo=D1[ko]
....: del D1[ko]
....: test_del_dictitem_by_exact_value(D2,vo,hash(ko))
....: assert D1 == D2
"""
return del_dictitem_by_exact_value(<PyDictObject *>D, <PyObject
*>value, h)
}}}
The following down-sized indirect test takes about 2 seconds and is thus
fine for a non-long test:
{{{
sage: from sage.misc.weak_dict import WeakValueDictionary
sage: class C(object):
....: def __init__(self, n):
....: self.n = n
....: def __cmp__(self, other):
....: return cmp(type(self),type(other)) or cmp(self.n,
other.n)
sage: B = 100
sage: L = [None]*B
sage: D1 = WeakValueDictionary()
sage: D2 = WeakValueDictionary()
sage: import gc
sage: for i in range(10000):
....: ki = floor(random()*B)
....: vi = C(floor(random()*B))
....: D1[ki] = vi
....: D2[ki] = vi
....: L[ki] = vi
....: del vi
....: ko = floor(random()*B)
....: if ko in D1:
....: del D1[ko]
....: L[ko] = None
....: assert D1 == D2
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/13394#comment:78>
Sage <http://www.sagemath.org>
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