`__future__` imports allow dots before them

[thatbirdguythatuknownot]

Bug report

Bug description:

__future__ imports don't check the amount of dots while checking from-import nodes for the module name, so they are still valid even if dots are put before the module name.

>>> from .__future__ import barry_as_FLUFL
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    from .__future__ import barry_as_FLUFL
ImportError: attempted relative import with no known parent package
>>> 1 <> 2
True

Is this intended? Allowing dots before the module name seems improper considering __future__ is supposed to be part of the stdlib.

CPython versions tested on:

3.12, 3.13

Operating systems tested on:

Windows

Linked PRs

• gh-118216: Don't consider dotted __future__ imports #118267

[terryjreedy]

What is weird is both raising an error and doing the pseudoimport anyway.

[JelleZijlstra]

Thanks @thatbirdguythatuknownot!

I merged the fix into main (3.13), so I'm closing this.

Arguably this is a bug that could also be fixed in 3.12, but I'd prefer to leave 3.12 unchanged, as the bug is rather harmless in practice and I feel core language behavior shouldn't change in a bugfix release.