[branch-2.10][fix][broker] Avoid infinite bundle unloading (#20822)

[Demogorgon314]

(cherry picked from commit 3f63768)

Motivation

The bundle ownership assignment logic doesn't know the previous unloaded broker when unloading happens. It might assign the bundle to the same broker. In this case, it might cause an infinite bundle unloading loop.

To resolve this issue, we can check the destination broker when doing the doLoadShedding stage. When the destination broker is the same as the current owner broker, we can skip this unload, and if it is different, we set the new owner in this stage.

Modifications

• Transfer the bundle to the new owner when needed to unload.

Verifying this change

See the ModularLoadManagerImplTest#testLoadShedding unit test.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[Demogorgon314]

@BewareMyPower Do you know why the CPP test failed?

[BewareMyPower]

Could we just ignore this test?

  File "/usr/local/lib/python2.7/dist-packages/bookkeeper/common/protobuf_helpers.py", line 18, in <module>
    from collections.abc import Mapping
ImportError: No module named abc

The error seems to be related to the bookkeeper-client dependency from the Python function. I think we can ignore it.

[BewareMyPower]

I removed this workflow: b0e2c0a