RFC-0018: Versioning and Compatibility

Status: Draft | Version: 0.1.0

1. Version domains

World schema, Component ABI, WIR, Domain IR, EIR, Runtime ABI, Plugin ABI, Network protocol, Resource schema are versioned independently.

Major: incompatible semantics/layout. Minor: backward-compatible additions. Patch: compatible corrections.

Canonical schema and IR serialization produce stable hashes. Artifacts reference the hashes they were compiled against.

A runtime must explicitly advertise accepted major/minor versions. Unknown major versions are rejected.

Schema migration is explicit and testable. Migration must declare source/target hashes and preserve required identity/state invariants.

Peers exchange protocol version and SchemaSetHash before state synchronization.

Changing any semantic input included in a compilation key invalidates the corresponding executable artifact.

No implicit downgrade may silently change world semantics. Incompatible artifacts fail closed.