crash with MIP_Problem

[videlec]

The following crashes Sage

sage: from sage.libs.ppl import Variable, Constraint_System, MIP_Problem
sage: x = Variable(0)
sage: y = Variable(1)
sage: cs = Constraint_System()
sage: cs.insert(x + y <= 2)
sage: MIP_Problem(2, cs, 0)
...
Unhandled SIGSEGV: A segmentation fault occurred in Sage.

If we replace 0 by x or y it also crashes... but with x-x or x+y or x+0it is fine!

This is just a problem of types.

CC: @vbraun

Component: linear programming

Author: Vincent Delecroix

Branch/Commit: f0c0346

Reviewer: Volker Braun, Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/19903

[videlec]

New commits:

d22dbfa

Trac 19903: fix MIP_Problem constructor

[videlec]

Branch: u/vdelecroix/19903

[videlec]

Commit: d22dbfa

[vbraun]

comment:2

cdef attribute initialization should be done from __cinit__, not __init__

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

980f125

Trac 19903: add a 'c'

[sagetrac-git]

Changed commit from d22dbfa to 980f125

[vbraun]

comment:4

lgtm

[mkoeppe]

comment:5

Patch no longer applies to current Sage, needs rebasing.

[mkoeppe]

Reviewer: Volker Braun

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

f0c0346

Trac 19903: fix MIP_Problem constructor

[sagetrac-git]

Changed commit from 980f125 to f0c0346