Not entirely convinced this implementation is the way to go; gonna look at some more examples before digging too deep into this. Marking as a draft for the time being.

Looks decent to me. Just needs a test. BTW version string can also have post1, and other version strings allowed by pypi..

That sort of inconsistency is part of why I think a more thorough implementation would be preferable. Something more along the lines of how python has the more robust sys.version_info. Being able to account for fringe situations would make this feel like a proper addition, instead of just making it less hacky to grab an existing piece of api.

I'd think you'd most likely be checking for major.minor.patch and the rest could be ignored?
At least for SCons releases, post releases are usually just packaging issues. I'd never release a post with functional differences.

I suppose that's fair, yeah. If I wanted to brainstorm something more, that'd probably go beyond the original scope of this PR. I'll get some tests up and running then undraft.

Can you add a blurb in the manpage and (maybe) users guide?
Here's where the manpage blurb would go: https://github.com/SCons/scons/blob/master/SCons/Script/SConscript.xml#L109

User's guide: https://github.com/SCons/scons/blob/master/doc/user/misc.xml#L112

The test for EnsureSConsVersion isn't happy now...

 TypeError: SConsEnvironment.EnsureSConsVersion() missing 1 required positional argument: 'minor':
  File "/tmp/testcmd.12132.jsexfe1p/SConstruct", line 2:
    env.EnsureSConsVersion(env.GetSConsVersion())


FAILED test of /home/runner/work/scons/scons/scripts/scons.py
	at line 673 of /home/runner/work/scons/scons/testing/framework/TestCommon.py (_complete)
	from line 775 of /home/runner/work/scons/scons/testing/framework/TestCommon.py (run)
	from line 458 of /home/runner/work/scons/scons/testing/framework/TestSCons.py (run)
	from line 72 of /home/runner/work/scons/scons/test/EnsureSConsVersion.py

Ahhh, silly me; I passed in the raw tuple instead of a broken-down version. Maybe I can add an overload to accept a tuple instead? Either way, it's an easy fix.

Haven't updated docs before so I'm unsure what I did wrong to make the test fail.

EDIT: Oh, duh. Needed to upload the generated files too. Probably.

EDIT2: Nevermind, I'm lost.