clean _cmp_ in rational.pyx

[fchapoton]

CC: @tscrim

Component: refactoring

Author: Frédéric Chapoton

Branch/Commit: ceb4c64

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/28945

[fchapoton]

Commit: 6b06817

[fchapoton]

Branch: u/chapoton/28945

[fchapoton]

New commits:

6b06817

some cleanup in rational.pyx (including removal of `_cmp_`)

[fchapoton]

comment:2

I am a bit surprised that it works, but it does.

[fchapoton]

comment:3

broken in 9.1.b2, apparently

[tscrim]

comment:4

So it is something with how comparisons are done in the ring extensions. The only thing I can really guess for why removing Rational._cmp_ breaks things is because that is being called because of the RingExtensionElement.__getattr__ that pulls methods from the _backend, which then gets Rational._cmp_ that overrides the RingExtensionElement._richcmp_ call. Hence, the RingExtensionElement._richcmp_ never actually got used. Yet, even if that is the case, I don't understand why it is broken.

[mkoeppe]

comment:5

Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.

[sagetrac-git]

Changed commit from 6b06817 to ceb4c64

[sagetrac-git]

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

af04177	some cleanup in rational.pyx (including removal of `_cmp_`)
ceb4c64	converting `__richcmp__` to _richcmp_

[fchapoton]

comment:7

hurrah, green bot !

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:8

Huzzah!

[vbraun]

Changed branch from u/chapoton/28945 to ceb4c64