Version selection is "latest tariff_version with effectiveFrom <= entry time",
but the publish handler accepted ANY effectiveFrom (defaulting to now). So an
admin could publish a version with a backdated effectiveFrom and silently
reprice sessions that had already entered — the retroactive rewrite the
versioning exists to prevent. Pricing itself was sound (quote resolves by entry
time; payment records tariffVersionId, freezing completed sessions); the leak
was the publish side only.
Reject effectiveFrom earlier than now (60s skew tolerance); future-dated
(scheduling a price change) stays allowed; bad ISO -> 400. Combined with
entry-time selection this is structural: once a car has entered, no later
publish can reprice it. Did not pin tariffVersionId onto vehicle_entry (not
needed). Verified 5/5 via inject against a copy of the live DB.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
julian
c9a2ef81a9