1722091 - Remove all Python behaviour where "sys.version_info" check is for Python < 3.9

Status: ASSIGNED

(Firefox Build System :: Mach Core, task, P3)

Description

[Mitchell Hentges [:mhentges] 🦀]

We have a bunch of code that only runs for older Python versions. Now that Mach always runs with 3.6+, we should detect the version_info checks that are now dead code, and delete accordingly. This should simplify our codebase nicely.

Notes:

• Careful for files that are used by Python 2 CI tasks. Some try runs associated with these changes would not go amiss.
• While doing this ticket, leave third-party usages of sys.version_info alone. That'll be fixed when we upgrade vendored packages.

Comment 1

[Taegeon Lee]

source code which sys.version_info < (3, 6): can be removed,
This code returns the command that some code requires Python 3.5 or greater.

if sys.version_info[0:2] < (3, 5):
print('run-task-wrapper requires Python 3.5+')
sys.exit(1)

Comment 2

[Sylvestre Ledru [:Sylvestre]]

Taegeon, would you like to give it a try?

Comment 3

[Yeakub Sadlil Bhuiyan]

Hi Sylvestre,

I'm a new contributor and I'd like to work on this bug. I've already started looking into removing sys.version_info checks for Python < 3.9 in some files. Is it okay to check Python < 3.9 as mach is using 3.9 now? check here

Could I take this bug? I’ll make sure to avoid third-party code and test changes properly.
And I'm interested in discussing my findings.

Thanks!

Comment 4

[Sylvestre Ledru [:Sylvestre]]

sounds good!

Comment 5

[jocelyne.ah1]

Picking this up as a good-first-bug, I found the work here already landed under bug 2018019 (already linked as "See also"), which resolved FIXED in Firefox 150 on 2026-02-27.

Per its comment 6, that stack:

• replaced mozbuild.util.memoized_property with functools.cached_property
• replaced mozbuild.util.memoize with functools.cache
• removed both hand-rolled classes.

I confirmed in current mozilla-central that util.py no longer defines either, and there are no remaining first-party imports of them. This matches the direction in comments 9 and 10. The original kwargs ask (comment 0) is covered too, since functools.cache handles kwargs.

Looks like this can be closed as RESOLVED DUPLICATE of bug 2018019.

Comment 6

[jocelyne.ah1]

Apologies, this comment was posted here by mistake; it was meant for bug 1637820. Please disregard.

Comment 7

[jocelyne.ah1]

Attachment: Bug 1722091 - Remove dead sys.version_info checks for Python < 3.9 r=sylvestre