*long* birds_other.rst doctest fails with mysterious error repeatedly on OS X

[williamstein]

wstein@bsd:~/build/sage-4.0.1$ ./sage -t -long "devel/sage/doc/en/bordeaux_2008/birds_other.rst"
sage -t -long "devel/sage/doc/en/bordeaux_2008/birds_other.rst"
A mysterious error (perhaps a memory error?) occurred, which may have crashed doctest.
         [44.5 s]
exit code: 768

----------------------------------------------------------------------
The following tests failed:


        sage -t -long "devel/sage/doc/en/bordeaux_2008/birds_other.rst"

wstein@bsd:~/build/sage-4.0.1$ ./sage -t  "devel/sage/doc/en/bordeaux_2008/birds_other.rst"
sage -t  "devel/sage/doc/en/bordeaux_2008/birds_other.rst"  
         [39.5 s]
 
----------------------------------------------------------------------
All tests passed!
Total time for all tests: 39.5 seconds
wstein@bsd:~/build/sage-4.0.1$ 

Component: number theory

Issue created by migration from https://trac.sagemath.org/ticket/6242

[williamstein]

comment:1

The failure does not happen in --verbose mode. :-(

[williamstein]

comment:2

This happens very sporadically, and is triggered by the parallel bernoulli number code by David Harvey.

[craigcitro]

comment:3

This is a duplicate of #6304, where David Harvey has made some more specific comments about what's causing this.