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Module snapshot

arkhe_kernel::persist

Module snapshot 

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KernelSnapshot — serializable point-in-time capture of kernel state.

Snapshot is independent from the WAL: WAL stores history (full replay from a fresh state), snapshot stores a single state at tick N. Hybrid recovery (snapshot at N + WAL from N+1) is the future integration; they ship as orthogonal mechanisms.

What snapshot includes:

  • All instances (entities, components, scheduler, ledger, id_counters, inflight_refs, wall_remainder, local_tick).
  • Kernel-level next_instance_id counter.

What snapshot excludes:

  • Box<dyn KernelObserver> (not Serialize).
  • ActionRegistry (fn pointers, not Serialize).
  • Attached WalWriter (independent persistence layer).

After Kernel::from_snapshot(...), the caller must re-register every Action that was active when the snapshot was taken, and re-attach observers/WAL as needed.

Determinism (A1): identical kernel state produces identical snapshot bytes — postcard-canonical encoding + BTreeMap iteration (A5).

Structs§

KernelSnapshot
Opaque point-in-time snapshot of kernel state.

Enums§

SnapshotError
Snapshot postcard round-trip failures.