DEP: drop support for Python 3.11, require 3.12+ by neutrinoceros · Pull Request #20223 · astropy/astropy

neutrinoceros · 2026-08-08T07:43:08Z

Description

As discussed in

close #18229
close #20184

After merge

Admin to update branch protection rules (carefully)

By checking this box, the PR author has requested that maintainers do NOT use the "Squash and Merge" button. Maintainers should respect this when possible; however, the final decision is at the discretion of the maintainer that merges the PR.

github-actions · 2026-08-08T07:43:19Z

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neutrinoceros · 2026-08-08T08:48:49Z

oldestdeps is failing with

ModuleNotFoundError: No module named 'six.moves'

(from cycler via matplotlib)
I don't understand it yet. six is actually installed there, as a declared dependency to cycler

edit: resolved by constraining six >= 0.16.0, which is the oldest version I cannot reproduce this error with.

neutrinoceros · 2026-08-08T11:14:55Z

Still hitting this error, and still getting six==1.9.0 despite the constraint. I'm suspecting a cache invalidation issue with tox, tox-uv, or OpenAstronomy/github-actions-workflows, but nothing conclusive yet.

neutrinoceros · 2026-08-08T12:41:37Z

The cached .tox actually isn't the (only ?) problem. I'm able to reproduce the issue locally without a .tox, and installing with uv directly gives me yet another version of six (1.5.0). That is, despite the resolver's logs clearly seeing my constraint:

DEBUG Adding transitive dependency for python-dateutil==2.7.0: six>=1.5
DEBUG Adding transitive dependency for python-dateutil==2.7.0: six>=0.16.0

This looks like something is broken in uv's resolver itself, but there's an additional source of error in the tox/tox-uv layer. Let's see if I can at least work around it for now by adding a direct requirement on six.

neutrinoceros · 2026-08-08T12:48:57Z

Nevermind, my constraint just contained a typo. The fix was

diff --git a/pyproject.toml b/pyproject.toml
index 7436fe9f2d..c3bfa6efb6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -829,7 +829,7 @@ required-environments = [
 constraint-dependencies = [
     "asdf>=2.15.1",
     "asdf-coordinates-schemas>=0.2.0",
-    "six>=0.16.0", # for Python 3.12+ compat
+    "six>=1.16.0", # for Python 3.12+ compat

     # via pytest
     # iniconfig 1.0.1 is the first version with proper wheels

mhvk

Thanks so much! I had been considering doing it myself and now realize how much I would've missed... Two comments, neither of which is essential.

mhvk · 2026-08-08T15:17:01Z

  }

-  Py_INCREF(Py_None);
  return Py_None;


Could replace (here and below) with Py_RETURN_NONE - which I like in that the reference counting is just hidden (i.e., one does not have to know Py_None is immortal).

good call. I'll push out a separate commit just in case and will squash it if everything stays green.

taldcroft

Fine for table

pllim · 2026-08-27T14:38:31Z

+
+    # pyupgrade (UP)
+    # temporarily delay upgrades to Python 3.12's PEP 695 typevars
+    # https://github.com/astropy/astropy/issues/20225


xref #20225

pllim · 2026-08-27T14:39:33Z

@mcara do you want to have a look at the WCS stuff? Thanks!

pllim

LGTM now. Thanks!

I will let you decide when to merge after a final comment period.

neutrinoceros · 2026-08-27T18:05:01Z

How about next week ? I just remembered this merger needs coordination with an owner anyway so I think it's best if you can handle it :)
thank you !

astrofrog · 2026-09-03T11:08:54Z

For the record I have updated the branch protection rules, and am doing a final review of this PR.

astrofrog

Looks good! A few small comments - once these are addressed I can approve and merge:

Check the docs for any instances of py311 - I think e.g. the test guide might mention it
I think codeql-analysis.yml should be updated to use Python 3.12 or later?
I think there are some references to Python 3.11 (check for "3.11") in astropy/config/paths.py
Should we update the minimum Python version in the scripts in scripts/?

astrofrog · 2026-09-03T11:20:53Z

    }

-    Py_INCREF(Py_None);
    result = Py_None;


Should this also be removed and replaced with Py_RETURN_NONE?

I don't feel confortable with this one; an early return would skip the exit block and leak a bunch of references

Ok np let's leave as-is

astrofrog · 2026-09-03T11:24:52Z


-    # see https://github.com/astropy/astropy/issues/18292
-    "array-api-strict<2.4 ; python_version<'3.12'",
+


Remove blank line?

not sure it's worth another round of CI so if that's the only request left I'll let you decide if you want to push it yourself

There are also a few comments in the top-level review, would you rather do these in a follow-up?

sorry I wrote this before I saw them. I should have addressed everything now

neutrinoceros · 2026-09-03T11:42:11Z

Should we update the minimum Python version in the scripts in scripts/?

I don't see a need for it. Running these scripts with older python versions than supported by the package is still possible, even if unlikely to be needed.

neutrinoceros added this to the v8.1.0 milestone Aug 8, 2026

neutrinoceros added Python 3.11 dependencies Pull requests that update a dependency file labels Aug 8, 2026

github-actions Bot added testing utils convolution labels Aug 8, 2026

neutrinoceros force-pushed the dep/drop-cp311 branch 4 times, most recently from 46db999 to fa7a591 Compare August 8, 2026 08:17

neutrinoceros force-pushed the dep/drop-cp311 branch 3 times, most recently from 2582b4c to b504b8f Compare August 8, 2026 11:09

neutrinoceros force-pushed the dep/drop-cp311 branch from 9b772ee to ee22592 Compare August 8, 2026 12:48

neutrinoceros force-pushed the dep/drop-cp311 branch from ee22592 to 3cb8083 Compare August 8, 2026 12:51

neutrinoceros mentioned this pull request Aug 8, 2026

RFC: upgrade from typing.TypeVar (legacy) to PEP 695 syntactic typevars #20225

Closed

neutrinoceros force-pushed the dep/drop-cp311 branch 5 times, most recently from 99d2d24 to 44e4a9d Compare August 8, 2026 13:20

mhvk reviewed Aug 8, 2026

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neutrinoceros force-pushed the dep/drop-cp311 branch 2 times, most recently from 89e41ff to afab778 Compare August 8, 2026 18:44

mhvk mentioned this pull request Aug 8, 2026

PERF: use scaler class instead of lambda for unit scale conversions #20183

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pllim mentioned this pull request Aug 26, 2026

TST: refine incorrect test requirements #20277

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taldcroft approved these changes Aug 27, 2026

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neutrinoceros force-pushed the dep/drop-cp311 branch from a7d326a to af1b444 Compare August 27, 2026 11:59

neutrinoceros marked this pull request as ready for review August 27, 2026 11:59

neutrinoceros force-pushed the dep/drop-cp311 branch 3 times, most recently from e100f38 to 21543cc Compare August 27, 2026 13:47

pllim reviewed Aug 27, 2026

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Comment thread .github/workflows/ci_workflows.yml Resolved

pllim reviewed Aug 27, 2026

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neutrinoceros force-pushed the dep/drop-cp311 branch from 21543cc to 0350746 Compare August 27, 2026 15:14

pllim approved these changes Aug 27, 2026

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astrofrog requested changes Sep 3, 2026

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github-project-automation Bot moved this from Reviewer approved to Review in progress in Cosmology, the Expansion Sep 3, 2026

neutrinoceros force-pushed the dep/drop-cp311 branch from 0350746 to 67c4eff Compare September 3, 2026 11:39

neutrinoceros requested a review from saimn as a code owner September 3, 2026 11:39

DEP: drop support for Python 3.11, require 3.12+

a31fd21

neutrinoceros force-pushed the dep/drop-cp311 branch from 67c4eff to a31fd21 Compare September 3, 2026 11:54

astrofrog approved these changes Sep 3, 2026

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github-project-automation Bot moved this from Review in progress to Reviewer approved in Cosmology, the Expansion Sep 3, 2026

astrofrog merged commit dde7834 into astropy:main Sep 3, 2026
43 of 45 checks passed

github-project-automation Bot moved this from Reviewer approved to Done in Cosmology, the Expansion Sep 3, 2026

neutrinoceros deleted the dep/drop-cp311 branch September 3, 2026 12:50

This was referenced Sep 3, 2026

RFC: avoid unnecessary buffer copies in gzip fits codec #20305

Merged

RFC: simplify historical compatibility-shim in an except block #20306

Merged

taldcroft mentioned this pull request Sep 17, 2026

Add type annotations to the astropy.table subpackage #20276

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1 task done


		# see https://github.com/astropy/astropy/issues/18292
		"array-api-strict<2.4 ; python_version<'3.12'",

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neutrinoceros commented Aug 8, 2026 • edited by astrofrog Loading Uh oh! There was an error while loading. Please reload this page.

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neutrinoceros commented Sep 3, 2026

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neutrinoceros commented Aug 8, 2026 •

edited by astrofrog

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