If you do a distutils --dry-run of an uninstalled
package, it will break when it attempts to check if the
non-installed  .py file needs bytecompiling. The
attached patch fixes this.

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The patch is incomplete - it does not update the docstring.

For symmetry with newer_group, it might be reasonable to
support the same three arguments.

Looking at the code, I find it unfortunate that it uses
os.path.exists, causing a stat call, and then does another
stat call to find the time stamp.

Perhaps it would be possible to implement newer in terms of
newer_group?

newer_pairwise should then probably also allow propagation
of the newer argument.

I’ll port this patch to distutils2 as part of #8501 and ask Tarek whether it can go in distutils too.

[Martin]
> Looking at the code, I find it unfortunate that it uses os.path.exists,
> causing a stat call, and then does another stat call to find the time stamp.

Are you noting the inefficiency of doing two stat calls instead of one, or saying that it should make none at all in dry-run mode?  My opinion is that a dry-run mode should not create any file nor make any changes, but reading files and calling processes that give info is fair game.