compileall shouldn't recompile up-to-date files with hash-based invalidation mode

Feature or enhancement

Proposal:

When you compile sources into .pyc files with python -m compileall while using the defaul invalidation mode (timestamp), the script verifies whether the compilation is necessary (the pyc file is up to date) and can skip it:

$> python -m compileall --invalidation-mode=timestamp script.py
Compiling 'script.py'...
$> python -m compileall --invalidation-mode=timestamp script.py
$>   # the compilation is skipped

When either of the hash invalidation modes is used instead, this doesn't work - the hash based check is not there. https://github.com/python/cpython/blob/main/Lib/compileall.py#L229

$> python -m compileall --invalidation-mode=checked-hash script.py
Compiling 'script.py'...
$> python -m compileall --invalidation-mode=checked-hash script.py
Compiling 'script.py'...
$>

I think it would make sense to add the same functionality for the other two invalidation modes as well?

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-121960

Start in Lib/compileall.py at the invalidation-mode handling around the linked line, and reproduce the behavior with the two python -m compileall commands shown for checked-hash and unchecked-hash modes. Done means repeated compilation of an up-to-date source is skipped for both hash invalidation modes, while preserving the existing timestamp behavior.