Stream resolution failure on Azure Pipelines macOS

[tstenner]

On Azure Pipelines macOS, only one stream can be resolved, all subsequent streams fail to resolve e.g. here.

When I download the binaries and run them on another mac, the tests pass:

macOS_artifacts.zip

[cboulay]

I'm not able to help right now, but I had a thought to try to run the build in a local VM that matched the Azure Pipelines VM. Then I realized I have no idea how Azure Pipelines works. Apparently they have these things called Agents, and you can run an agent locally. It's not clear to me if the Agent is the VM or if it's the host for the VM.

Anyway, running an agent locally may make it easier to debug. Maybe the agent has networking constraints?

[tstenner]

I think I found the source of the problem.

By default, 127.0.0.1 is set as machine-local multicast address but it's a unicast address so only the last socket to bind to the interface will receive the query packet (and answer it).

Removing it causes most tests to fail, because instead of only the first stream no stream at all can be resolved. Not ideal, but a good start for further investigations 🤷‍♂️