set -euo pipefail aborted the script on the diff pipeline one line
before the cp that restores the pre-run oracle, so --full left a
regenerated fixture file in the working tree while printing that
nothing had been overwritten. Appended || true.
Recorded as F-033. The fix is not yet exercised: the restore branch
runs only under --full and has not been entered since the change.
TheRON
b67cc1290e