[Python-Dev] The endless GIL debate: why not remove thread support instead?

["Martin v. Löwis"]

> OK, but how close is it to providing isolation for threads running
> under the control of the GIL? 

They won't be indedepent. If an extension module has a global variable,
that will be shared across interpreters. If that variable supports
modifiable state, such modifications will "leak" across interpreters.

For example, there will be only a single object class. With that in
mind, take a look at object.__subclasses__(); it would provide access
to all classes, including those in the other interpreters. Likewise,
gc.get_objects() will give you the complete list of all objects. So
the isolation is not strong enough to run untrusted code isolated
from other code.

Regards,
Martin