A checkpoint write is unnecessary if it does not change the semantics of
the data currently stored in the checkpoint. We currently perform
unnecessary checkpoint writes in two cases:
- Same steps where no aspect of the resource's state has changed
- Replace steps, which exist solely for display purposes
The former case is particularly bothersome, as it is rather common to
run updates--especially in CI--that consist largely/entirely of these
same steps.
These changes eliminate the checkpoint writes we perform in these two
cases. Some care is needed to ensure that we continue to write the
checkpoint in the case of same steps that do represent meaningful
changes (e.g. changes to a resource's output properties or
dependencies).
Fixes#1769.
effff869a1