Hi Dave,
your suggestion is interesting. I want to add some remarks though. As i understand, a tag change in a submodule would trigger any configuration for which repositories exist, that use that submodule. Therefore it is important, that the change is relevant only, if the submodules HASH is referenced by the detected tag.
Also there is an implication with the UI. How is it is possible to recognize, that a virtual changeset was created (and thus triggering a build) by a tag change of a submodule?
Please note, that we have configured all of our repositories to poll “never”, but be notified by TFS Webhooks.
Thomas