Permanent field identity and widening constraints

Context

Field definitions govern information collected over time and stored by several owners. Definition changes must preserve that information’s interpretation.

Decision

Custom field identity and value type are fixed, configuration changes preserve the existing value range, and archival retains both reserved keys and stored values.

Alternatives Considered

Retyping with automatic conversion: Conversion can reinterpret existing information without an explicit migration contract. Narrowing after scanning values: This needs a reliable check across every owning value store and is not implemented here. Deleting definitions: Owner-held values would lose their definition, and reusing the key could give retained data another meaning.

Consequences

Archival does not release a property key for another meaning. Stable option identities remain present through option archival. Dependent conditions must change before their referenced custom-object property can be archived.