#14471: Exception KeyError: in WeakValueDictionary remove ignored
---------------------------+------------------------------------------------
Reporter: vbraun | Owner: rlm
Type: defect | Status: new
Priority: major | Milestone: sage-5.10
Component: memleak | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Description changed by vbraun:
Old description:
> Under some circumstances the !WeakValueDictionary remove callback is
> being called when the internal dictionary is in a bad state. The attached
> patch to demonstrate the issue just calls `hasattr` from the displayhook,
> which ends up generating weak references somewhere. The exact place for
> where the exception occurs depends on the garbage collector, but I always
> do get some unwanted exceptions with it.
> {{{
> sage -t devel/sage/sage/matrix/matrix0.pyx
> Exception KeyError: (((<class 'sage.matrix.matrix_space.MatrixSpace'>,
> Callable function ring with arguments (x, y), 2, 2, False), ()),) in
> <function remove at 0x18d8758> ignored
> **********************************************************************
> File "devel/sage/sage/matrix/matrix0.pyx", line 3370, in
> sage.matrix.matrix0.Matrix.is_hermitian
> Failed example:
> B.is_hermitian()
> Expected:
> True
> Got:
> Exception KeyError: (((<class 'sage.categories.algebras.Algebras'>,
> Callable function ring with arguments (x, y)), ()),) in <function remove
> at 0x18d8758> ignored
> True
> }}}
New description:
Under some circumstances the !WeakValueDictionary remove callback is being
called when the internal dictionary is in a bad state. The attached patch
[attachment:trac_14471_demonstrate.patch] to demonstrate the issue just
calls `hasattr` from the displayhook, which ends up generating weak
references somewhere. The exact place for where the exception occurs
depends on the garbage collector, but I always do get some unwanted
exceptions with it.
{{{
sage -t devel/sage/sage/matrix/matrix0.pyx
Exception KeyError: (((<class 'sage.matrix.matrix_space.MatrixSpace'>,
Callable function ring with arguments (x, y), 2, 2, False), ()),) in
<function remove at 0x18d8758> ignored
**********************************************************************
File "devel/sage/sage/matrix/matrix0.pyx", line 3370, in
sage.matrix.matrix0.Matrix.is_hermitian
Failed example:
B.is_hermitian()
Expected:
True
Got:
Exception KeyError: (((<class 'sage.categories.algebras.Algebras'>,
Callable function ring with arguments (x, y)), ()),) in <function remove
at 0x18d8758> ignored
True
}}}
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14471#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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