bug in comparisons of infinite values

[xcaruso]

sage: if log(2)*Infinity == Infinity: print "Hello"
....: 
type = 214729600
** Hit STUB**: invalid type: is_zero() type not handled
terminate called after throwing an instance of 'std::runtime_error'
  what():  stub

------------------------------------------------------------------------
Unhandled SIGABRT: An abort() occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and 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.
------------------------------------------------------------------------

Depends on #18362

Component: symbolics

Keywords: comparaison Infinity pynac

Author: Ralf Stephan

Branch/Commit: f4fc186

Reviewer: Marc Mezzarobba

Issue created by migration from https://trac.sagemath.org/ticket/13326

[videlec]

comment:5

The bug is still here on sage-6.7.beta1!

[rwst]

Changed keywords from comparaison Infinity to comparaison Infinity pynac

[rwst]

comment:8

The crash itself is unnecessary and will be fixed by #14211.

The invalid type in Pynac is pynac/pynac#35

[rwst]

Branch: u/rws/bug_in_comparisons_of_infinite_values

[rwst]

New commits:

23892cb	18362: upgrade to pynac-0.3.7; fix one changed doctest result
f4fc186	13326: doctest

[rwst]

Author: Ralf Stephan

[rwst]

Dependencies: #18362

[rwst]

Commit: f4fc186

[mezzarobba]

Reviewer: Marc Mezzarobba

[vbraun]

Changed branch from u/rws/bug_in_comparisons_of_infinite_values to f4fc186