PEP 440: Note case where pkg_resources subsequently changed to match the PEP

[ncoghlan]

According to https://mail.python.org/archives/list/distutils-sig@python.org/message/OXN53BWJYSMFK535OWUJR5MAXEIBWRBX/, some time since https://www.python.org/dev/peps/pep-0440/#summary-of-differences-from-pkg-resources-parse-version was written, pkg_resource.parse_version started ordering local version numbers the same way that PEP 440 does.

@jaraco Do you have any idea when that might have changed? https://setuptools.readthedocs.io/en/latest/history.html doesn't call it out explicitly anywhere, so I'm wondering if it might have happened inadvertently while converging on a shared supported library.

[jaraco]

Using bisect, I found the relevant commit is pypa/setuptools@9382fa0.

setuptools master $ git bisect start --term-new=fixed --term-old=unfixed                                                                                                       
setuptools master $ git bisect fixed master                                                                                                                                    
setuptools master $ git bisect unfixed 5.0                                                                                                                                     
Bisecting: 1803 revisions left to test after this (roughly 11 steps)
[0fc24e1a277513a303d845b38ac71f854fbc8f65] Merge pull request #637 from stepshal/comparison
setuptools master $ git bisect run python3.5 -c 'import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")'                
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 902 revisions left to test after this (roughly 10 steps)
[5e00a02ea1f7473c952d4d359891db4f53ac1778] Disable warning of LegacyVersion in parsed_version. This functionality should be called explicitly at whatever times are appropriate for the warning. Fixes #307.
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 450 revisions left to test after this (roughly 9 steps)
[de1af740bc79592faac63b3c0c8d50383b373dd4] Extract common operation of dedent and left strip
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 225 revisions left to test after this (roughly 8 steps)
[d195bc900beccb22c8de243416c40564ea28402f] Remove unused import
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Bisecting: 112 revisions left to test after this (roughly 7 steps)
[20ac482786bc7622f67df8ab13810fde9fd850ac] Merge pull request #20 from dstufft/dont-warn-empty
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 56 revisions left to test after this (roughly 6 steps)
[dd32e04bc63ac7bd9f70b9684b76bdb283b6111d] Bumped to 7.0 in preparation for next release.
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Bisecting: 28 revisions left to test after this (roughly 5 steps)
[4ae526d52609fe2a7515d87e4c0d047a826411a7] Always use the vendored copy of packaging
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 13 revisions left to test after this (roughly 4 steps)
[affa001a6767efee24b4d6bc1a2f04eb7aeea65b] Merge
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Bisecting: 6 revisions left to test after this (roughly 3 steps)
[7d9c21a893431798ba77edd62b5490ff4ce47ecf] Prefer packaging library if available.
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 3 revisions left to test after this (roughly 2 steps)
[c5d53df96d27f54f40ae4df974a74e1536f45ae1] Merge github pull request #13 (dstufft/setuptools:use-packaging).
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 0 revisions left to test after this (roughly 1 step)
[9382fa0c05e533400613e1c7c0a777cabb463390] Implement PEP 440 by using the packaging library
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AssertionError
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[84c9006110e53c84296a05741edb7b9edd305f12] Add a vendored copy of packaging
running python3.5 -c import pkg_resources; assert pkg_resources.parse_version("1.0.0+dev") <= pkg_resources.parse_version("1.0.0")
9382fa0c05e533400613e1c7c0a777cabb463390 is the first fixed commit
commit 9382fa0c05e533400613e1c7c0a777cabb463390
Author: Donald Stufft <donald@stufft.io>
Date:   Thu Sep 4 21:04:06 2014 -0400

    Implement PEP 440 by using the packaging library

:100644 100644 a6e27372d6af1d051b79447bc2272106e1f4efed e458d76c33d3005aa395af5409572b42209bb63f M      CHANGES.txt
:040000 040000 8e303f14da2aaef6b712d6d2d04a08747ff8aca2 d19044d021fb9104d0466f867ff26be63217bdc2 M      docs
:100644 100644 517298c90dbf2bb39b59a3e5cf01927a78e18818 b59ec52364771234ce4aca765a54be28ef72aaee M      pkg_resources.py
:040000 040000 cd6c875b6898b3055266ab32db69f9b5358a9473 fa17935a9e6a59198a000194dac497a54b5f721f M      setuptools
bisect run success

[jaraco]

So Setuptools 6.0 was the version.

[ncoghlan]

Thanks!

[AA-Turner]

@ncoghlan is there any action to be taken here? I'll close the issue if not.

A

[CAM-Gerlach]

If there's an update needed, perhaps it should be on the PyPA specifications page instead

[ncoghlan]

This only affects the part of the PEP that compares it to the way pkg_resource.parse_version used to work, so there isn't any impact on the spec itself, just on the background info.

I posted a PR to add a note about it, which will close this issue when merged.