Pynac should check for errors when calling PyObject_RichCompareBool()

[embray]

There are a number of methods in pynac's ginac/numeric.cpp module that don't check for error results from PyObject_RichCompareBool (which returns -1 on error).

This leads to unhandled exceptions that, on Python 2, were somewhat by luck being cleared via PyObject_Clear() later in the call stack.

On Python 3, the interpreter asserts PyErr_Occurred in more places and we don't get so lucky.

Upstream PR: pynac/pynac#297

Upstream: Fixed upstream, in a later stable release.

CC: @rwst

Component: packages: standard

Keywords: pynac

Issue created by migration from https://trac.sagemath.org/ticket/24522

[embray]

comment:2

Yes, this still looks like what I described. On Python 3 the exception leaks out, and slightly later on a call to PyObject_IsInstance in turn calls the type's __instancecheck__ which goes through _PyObject_FastCallDict which in turn asserts PyErr_Occurred.

On Python 3 there is no _PyObject_FastCallDict, no assertion checks on PyErr_Occurred in the relevant code path, and eventually that error gets cleared.

[embray]

comment:4

I have an upstream fix for this ready--just need to make a PR...

[embray]

Upstream: Reported upstream. No feedback yet.

[rwst]

Changed upstream from Reported upstream. No feedback yet. to Fixed upstream, in a later stable release.

[embray]

comment:7

Thanks! This is low priority for now, as it only affects a few things on Python 3. We can close this along with the next update to pynac in Sage.

[fchapoton]

comment:8

Can we close this now ?