The current implementation in amqpdriver.py uses an explicit conditional to handle a rare edge case where os.getpgrp() may return 0 (for example when running under the crun container runtime):

proc_id = self.pg if self.pg != 0 else os.getpid()

This patch simplifies the expression by using the more idiomatic Python fallback pattern:

proc_id = self.pg or os.getpid()

Using or preserves the same behavior, correctly handling any falsy values (0, None, etc.), while making the code shorter and more readable.
This change does not alter behavior — it’s purely a readability improvement on top of the previous fix for the crun runtime case.

Rationale

Keeps the same behavior for pg=0 and pg=None

More Pythonic and concise

Improves code readability and maintainability

Impact

None on functionality.
The change only affects readability and expression style.

References

Gerrit change: https://review.opendev.org/c/openstack/oslo.messaging/+/965938