garbage collection deleting children resources

[whereismyjetpack]

Hi friends!

I'm testing the garbage collection feature, and i'm noticing that some operators' children are being garbage collected!

example:
Prometheus operator creates a statefulset, and the statefulset gets cleaned up when gc runs

we've identified that this is because the statefulset is mirroring the labels from the Prometheus object

both the Prometheus object and the StatefulSet get this

  annotations:
    flux.weave.works/sync-checksum: ca0b295832f409e52084f1db0f0185d097603642

We had talked in #flux about some of the ways we could handle this

Proposed ideas:
1.) use git repo history for gc @hiddeco pointed out that this may be problematic
2.) use a combination of labels to identify that a hash belongs to a type, for example that hash above belongs to a Prometheus so fluxd won't garbage collect a StatefulSet

questions?
what if a Foo creates a Foo? maybe the labels would have a hash of some kind to identify the resource it belongs to?