Well, at least for now I’m going with the following:
#! /bin/bash
if [ "$CACHED_COMMIT_REF" != "$COMMIT_REF" ]; then
echo "New Commit - Checking for changes..."
git diff --quiet $CACHED_COMMIT_REF $COMMIT_REF
exit
fi
echo "Looks like we already deployed this commit, proceeding with forced re-deploy..."
exit 1
slightly adapted for our purposes, but this would be a “closer to default” behavior script based on the one from the docs.