On May 10, 2019, at 04:07, Josh Rosenberg <report@bugs.python.org> wrote:
> 
> I've seen far too many cases where Python code targeting Linux intentionally uses the COW benefits of fork for multiprocessing to think it would be a good idea to change the default start method there without *some* sort of deprecation period.

We need to resolve this for 3.8, and given that I think we have clear consensus to change the default on macOS to spawn to avoid the crashes, let’s do that.  We’ll need to update the documentation.

Then if we don’t have consensus to change the default on Linux, let’s issue a DeprecationWarning for the default ‘fork’ method in 3.8 and change it to ‘spawn' in 3.9.

Do we want to issue a warning on set_start_method(‘fork’) on macOS, given that it’s unlikely to be safe?