#10963: More functorial constructions
-------------------------------------+-------------------------------------
Reporter: nthiery | Owner: stumpc5
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-6.1
Component: categories | Resolution:
Keywords: days54 | Merged in:
Authors: Nicolas M. Thiéry | Reviewers: Simon King, Frédéric
Report Upstream: N/A | Chapoton
Branch: | Work issues: Detect and fix
public/ticket/10963 | Heisenbugs
Dependencies: #11224, #8327, | Commit:
#10193, #12895, #14516, #14722, | 5ccf253b17c151d8e773037ac634a64f84f03075
#13589, #14471, #15069, #15094, | Stopgaps:
#11688, #13394, #15150, #15506 |
-------------------------------------+-------------------------------------
Comment (by nbruin):
Would it make sense to put this debugging on a different ticket? The
length of
this one makes working on it excruciating (especially tickets with a lot
of
comments seem particularly slow with trac) and the debugging involved in
this is
a bit of a side-issue.
Since it is a python recursion bug, we should probably look at the ".py"
files
involved, so I did a grep:
{{{
$ grep "^#.*py:[0-9]*$" crash_functorial_constructions.log
#24 0x00007fee3aa07580 in __classget__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:507
#38 0x00007fee3aa07580 in base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:243
#47 0x00007fee3aa07580 in _base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:381
#57 0x00007fee3aa07580 in axiom_of_nested_class() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:281
#66 0x00007fee3aa07580 in __classget__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:507
...
#710 0x00007fee3aa07580 in base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:243
#719 0x00007fee3aa07580 in _base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:381
#729 0x00007fee3aa07580 in axiom_of_nested_class() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:281
#738 0x00007fee3aa07580 in __classget__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:507
...
#2768 0x00007fee3aa07580 in base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:243
#2777 0x00007fee3aa07580 in _base_category_class_and_axiom() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:381
#2787 0x00007fee3aa07580 in axiom_of_nested_class() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:281
#2796 0x00007fee3aa07580 in __classget__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category_with_axiom.py:507
#2809 0x00007fee3aa07580 in extra_super_categories() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/sets_cat.py:1826
#2812 0x00007fee3aa07580 in super_categories() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/covariant_functorial_construction.py:399
#2815 0x00007fee3aa07580 in _super_categories() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:1015
#2823 0x00007fee3aa07580 in _all_super_categories() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:885
#2831 0x00007fee3aa07580 in _super_categories_for_classes() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:1040
#2839 0x00007fee3aa07580 in _make_named_class() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:1246
#2843 0x00007fee3aa07580 in subcategory_class() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:1290
#2851 0x00007fee3aa07580 in __init__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:504
#2856 0x00007fee3aa07580 in __init__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/covariant_functorial_construction.py:355
#2867 0x00007fee3aa07580 in __classcall__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/structure/unique_representation.py:1021
#2875 0x00007fee3aa07580 in __classcall__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/category.py:465
#2883 0x00007fee3aa07580 in category_of() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/covariant_functorial_construction.py:269
...
#3180 0x00007fee3aa07580 in WithRealizations() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/with_realizations.py:181
#3183 0x00007fee3aa07580 in __init__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/combinat/sf/sf.py:767
#3194 0x00007fee3aa07580 in __classcall__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/structure/unique_representation.py:1021
#3206 0x00007fee3aa07580 in __init__() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/combinat/species/generating_series.py:327
#3217 0x00007fee3aa07580 in CycleIndexSeriesRing() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/combinat/species/generating_series.py:314
...
}}}
So it would seem that the creation of a `SymmetricFunctions` object leads
via a
long chain of `WithRealizations` calls to the creation of a category
(frame
`#2851`) which calls `extra_super_categories` (frame `#2809`) and then
goes off
to a long chain of calls involving `axiom_of_nested_class` and
`base_category_class_and_axiom` (66 deep apparently)
What probably causes the eventual error is that building such a deep call
chain
requires memory and thus can trigger a garbage collection, at which point
there
may be some extra room required on top of the python call stack to execute
the
various weakref callbacks. Apparently that room isn't there.
66 calls is suspiciously deep, but perhaps symmetric functions
realizations are
indeed extremely complicated. Let's look at the relevant frames:
{{{
#2807 0x00007fee2dcdcd6d in
__pyx_tp_descr_get_4sage_4misc_11lazy_import_LazyImport() at
/home/vbraun/Code/sage/src/sage/misc/lazy_import.c:7252
#2808 0x00007fee3a9a2c00 in _PyObject_GenericGetAttrWithDict() at
/home/vbraun/Code/sage/local/var/tmp/sage/build/python-2.7.5.p1/src/Objects/object.c:1439
#2809 0x00007fee3aa07580 in extra_super_categories() at
/home/vbraun/Code/sage/local/lib/python2.7/site-
packages/sage/categories/sets_cat.py:1826
> 1826 return [Sets().Facade()]
}}}
There seems to be a lazy import involved, and indeed, there seems to be a
cycle
of 24 frames that keeps repeating from this point on. So one hypothesis
might be
that somehow some lazy import resolution doesn't go right, which confuses
the
`base_category_class_and_axiom` code, which them keeps recursing. Perhaps
a
script like this rings some bells with the persons who are familiar with
the
code?
--
Ticket URL: <http://trac.sagemath.org/ticket/10963#comment:242>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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