[Python-Dev] PEP 567 v3 (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Thu Jan 18 03:03:52 EST 2018

On Wed, 17 Jan 2018 20:53:42 -0500 Yury Selivanov <yselivanov.ml at gmail.com> wrote:

Proposed by Antoine Pitrou, this could enable transparent cross-process use of Context objects, so the Offloading execution to other threads example would work with a ProcessPoolExecutor too. Enabling this is problematic because of the following reasons: 1. ContextVar objects do not have _module_ and _qualname_ attributes, making straightforward pickling of Context objects impossible. This is solvable by modifying the API to either auto detect the module where a context variable is defined, or by adding a new keyword-only "module" parameter to ContextVar constructor. 2. Not all context variables refer to picklable objects. Making a ContextVar picklable must be an opt-in.

This is a red herring. If a value isn't picklable, pickle will simply raise as it does in other contexts. You should't need to opt in for anything here.

Regards

Antoine.

More information about the Python-Dev mailing list