> PR 18161 fixes race condition by using "from ... import ..."
> which waits until the module be completely initialized if the specified
> names are not set.

Correct me if I'm wrong, but I think the behavior of 'import lzma' in
this case (vulnerable to race conditions) is not as intended? Shouldn't we also fix
the 'import' statement itself?

In general, I understand that due to how dynamic Python is, it might not be
possible to load every single name at import time using `import` and using
`from x import y` brings more determinism (because we have a safeguard now).

But, looking at the stacktrace from ipython the problem lies in a sequence of
import statements, not dynamic python coding. Shouldn't the importing mechanism
be more deterministic in such case? For sure, it should not return an empty module
(this is the case when race condition occurs).

I think a race condition caused by simply using `import` statements
(not `from x import y`) is a big caveat in the statement itself and how python
imports work.

Haven't checked if the cause is isolated to how tarfile works, or works in general, though :-(