Triggering CI/snap builds on changes to snapcraft parts

[Loïc Minier]

Hi!

Currently, setting up a snap build from a git branch in Launchpad or via
build.snapcraft.io is a pleasure, and this allows for an easy CI whenever a
change is pushed to the repo. But non-trivial projects have multiple
components to build to deliver the snap, with chains of build-deps.

What's the best practice to trigger snap builds/CI builds when changes are
pushed to build-dependencies / parts of a snap? Should there be a way to
parse part sources in snapcraft.yaml and check whether these have changed?

Thanks!
- Loïc Minier