For Sage 9.2: Remove python 2 support from sagelib
Closed this issue · 50 comments
Python 3 support (#15530) was completed for Sage 9.0 (thanks in particular to the leadership of Frédéric Chapoton). Official support for Python 2.7 by the CPython core developers is ending January 1, 2020.
To enable major package upgrades and other changes that require Python 3.x (#29141),
this ticket removes Python 2 support in Sage for Sage 9.2.
Depends on #26403
Depends on #28660
CC: @timokau @fchapoton @dimpase
Component: python3
Keywords: days101
Author: Erik Bray
Branch: f368e32
Reviewer: Dima Pasechnik
Issue created by migration from https://trac.sagemath.org/ticket/28000
Description changed:
---
+++
@@ -1 +1,7 @@
+Python 3 support (#15530) is nearly complete (thanks in particular to the dogged efforts of Frédéric Chapoton).
+Official support for Python 2.7 by the CPython core developers is ending January 1, 2020.
+
+Because Sage's Python 3 support is likely to make it in just under the wire, there will still be some time while Sage continues to support Python 2; we probably will not want to drop it as soon as Python 3 support is complete. But the sooner the better.
+
+This task is to remind us to do that.What needs to be done for this ticket?
Go through and remove all hacks related to supporting Python 2. It will be interesting to see how big a change it takes even now. It's rather early to go through and do that in earnest, but it would be fun to just try and see what it takes.
Changed keywords from none to days101
One example: #27696 (remove the doctesting hack for "long", which just converts it to "int" when using Python 3.
Also, this ticket can be set as a dependency for other tickets that depend on the
removal of Python 2 support. Many dependency upgrades will depend on that.
Might it make sense to migrate the whole Jupyter part to Python3-only versions
before completely removing Python 3 support? Even when building Sage for
Python 2, we ship Python 3 too anyway.
I made some progress at days101 removing all dependency on the six module for Python 2/3 support and that alone was a HUGE change (and not even quite finished yet). Will post a branch once I'm done with that.
Here's some of my progress on this so far: Probably one of the biggest, most pervasive steps, being complete removal of dependency on six.
Of course, this step is optional--we can keep using six while otherwise dropping support for Python 2. But this makes it quite explicit.
It's pretty hard to avoid making a patch bomb of this. It's not all bad though--I started this months ago, and then once I got it finished I rebased on current develop and only had about a dozen minor merge conflicts.
Branch: u/embray/python3/ticket-28000
Author: Erik Bray
Branch pushed to git repo; I updated commit sha1. New commits:
8f3cacb | Trac #28000: Remove sagelib dependency on six |
Commit: 8f3cacb
Branch pushed to git repo; I updated commit sha1. New commits:
736c7a2 | One Python 2-specific block that did not use six.PY2. |
Other tasks:
- remove or revise the doctests labeled
# py2. Ideally, all such tests should be evaluated on a case-by-case basis, some should just be removed, but perhaps some should be modified to work with Python 3. - #28426: with a Python 3 build, do not build Python 2.
- remove some packages which are only necessary with Python 2:
typing(#28499) is the only one I know of currently, but I wouldn't be surprised if there were others. - remove the legacy Sage notebook — at least, I don't think it works with Python 3 now, and I don't think anyone is working on it. This means we should deprecate it ASAP. (#25837)
My branch for this has some other in-progress changes that it seems I haven't pushed yet. I'll do so next time I rebase this branch.
Oh right, one of the changes I started was to remove unnecessary from __future__ imports, but it seems until we have #26403, to my slight surprise, some of them are still needed in Cython modules, e.g. to have the print() function by default.
Rebased, but no guarantee there are no new bugs or new uses of six I didn't miss. I didn't check yet.
Updated again after removing two new uses of six that have since appeared.
Do we remove all doctests tagged # py2 here or on a separate ticket?
You could do it here, or a separate ticket (and make it a dependency of this ticket). It's going to be a patch bomb no matter what, but I don't see the harm in trying to split it up wehre possible.
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
b4fa8db | Trac #28000: Remove sagelib dependency on six |
0ff5ac8 | Trac #28000: One Python 2-specific block that did not use six.PY2. |
0e37a95 | Trac #28000: Get rid of most `__nonzero__` references and/or replace them with __bool__ |
Rebased on 9.0
Description changed:
---
+++
@@ -5,3 +5,6 @@
Because Sage's Python 3 support is likely to make it in just under the wire, there will still be some time while Sage continues to support Python 2; we probably will not want to drop it as soon as Python 3 support is complete. But the sooner the better.
This task is to remind us to do that.
+
+See also:
+- #29141: Meta-ticket: Upgrades and other changes that require dropping py2 support or separate package versions for py2/py3Description changed:
---
+++
@@ -1,10 +1,5 @@
-Python 3 support (#15530) is nearly complete (thanks in particular to the dogged efforts of Frédéric Chapoton).
+Python 3 support (#15530) was completed for Sage 9.0 (thanks in particular to the leadership of Frédéric Chapoton). Official support for Python 2.7 by the CPython core developers is ending January 1, 2020.
-Official support for Python 2.7 by the CPython core developers is ending January 1, 2020.
+To enable major package upgrades and other changes that require Python 3.x (#29141),
+this ticket removes Python 2 support in Sage for Sage 9.2.
-Because Sage's Python 3 support is likely to make it in just under the wire, there will still be some time while Sage continues to support Python 2; we probably will not want to drop it as soon as Python 3 support is complete. But the sooner the better.
-
-This task is to remind us to do that.
-
-See also:
-- #29141: Meta-ticket: Upgrades and other changes that require dropping py2 support or separate package versions for py2/py3Needs rebasing!
Related: #27826
Changed branch from u/embray/python3/ticket-28000 to u/jhpalmieri/python3/ticket-28000
Rebased. I haven't seen activity from embray for a while. Perhaps this is ready for review?
New commits:
f368e32 | trac 28000: rebase commits from Erik M. Bray : |
Let's see if this finds a reviewer
Reviewer: Dima Pasechnik
testing.
OK, this makes sense and appears to work. A long, but straightforward patch, also touching quite a bit of whitespace (which probably could have waited for another place, but OK).
Should removing Python2 spkg be done elsewhere?
Changed branch from u/jhpalmieri/python3/ticket-28000 to f368e32
＼(＾O＾)／
Hopefully the divergence between sage-the-distribution and sage-on-distro will decrease now and packaging will become simpler again.
Thanks for finally getting this ticket merged! Sorry I haven't had much time to work on it. As others have noted this does not take care of all tasks related to dropping Python 2 support--it was just me doing as much as I could in one place. Took hours!
Does anyone know of any docker setups from tox.ini that have Python 3.5?
Python 3.5 will be gone in Sept, why would wr spend time trying to support it?
This accidentally broke the Macaulay2 interface. Follow up at #29759 with a trivial fix.