id	summary	reporter	owner	description	type	status	priority	milestone	component	resolution	keywords	cc	work_issues	upstream	reviewer	author	merged	dependencies	stopgaps
1374	[with patch] segfault in coercion with matrices and ints	craigcitro	robertwb	"This is the bug that was causing #1231; the fix there was easy, but as cwitty points out, the underlying bug is still there. It's something specifically to do with an entry becoming 0 in a matrix. I haven't looked into this at all; it's probably easy pickings for someone who knows the coercion code.

Here's a sample session:

{{{
sage: M = MatrixSpace(GF(5),2,2)

sage: A = M([1,0,0,1])

sage: A - int(-1)
 
[2 0]
[0 2]

sage: B = M([4,0,0,1])

sage: B - int(-1)


------------------------------------------------------------
Unhandled SIGBUS: A bus error occured in SAGE.
This probably occured because a *compiled* component
of SAGE has a bug in it (typically accessing invalid memory)
or is not properly wrapped with _sig_on, _sig_off.
You might want to run SAGE under gdb with 'sage -gdb' to debug this.
SAGE will now terminate (sorry).
------------------------------------------------------------


}}}"	defect	closed	critical	sage-2.8.15	coercion	fixed