SPEC-007

Version History

Status: Draft

Standard: CKS Runtime

Category: Runtime Version History Specification

1. Purpose

This specification defines the canonical Runtime Version History model.

Version History records the evolution of Runtime Session operational state over time.

It provides the canonical mechanism for observing, restoring and reasoning about historical Runtime state while preserving the semantic guarantees established by CKS Core.

2. Scope

This specification defines:

Version History;
Runtime Versions;
Version creation;
Version immutability;
Session restoration;
Runtime responsibilities.

Implementation-specific version control mechanisms are intentionally omitted.

3. Version Definition

A Runtime Version is an immutable snapshot of committed Runtime operational state.

Each Version represents the operational state of a Runtime Session immediately following successful Transaction completion.

Versions capture operational evolution.

Versions do not capture ownership of semantic meaning.

Versions do not redefine knowledge semantics.

4. Version Creation

Versions are created exclusively after successful Transaction commitment.

Conceptually:

Session
      │
Transaction
      │
Commit
      │
Version

In the reference implementation, version creation is handled by the VersionManager.create method, which is called from ExecutionPipeline.commit only after a transaction has been successfully validated and committed.

Version creation is an observable consequence of successful Transaction completion.

Runtime implementations shall not create Versions at arbitrary points during Session execution.

No Runtime component may create Versions independently of committed Transactions.

5. Version Immutability

Runtime Versions are immutable.

Once created, a Version shall never be modified.

Immutability applies to:

committed Runtime state;
Version identity;
Version metadata;
Version ordering information.

The reference implementation enforces immutability by making RuntimeVersion a frozen dataclass with __post_init__ performing a deep copy of the knowledge_structure and metadata fields, ensuring that no mutable objects are shared with the live session.

Subsequent Runtime evolution produces new Versions rather than altering existing ones.

6. Version History

Version History is an ordered collection of Runtime Versions belonging to a Runtime Session.

Conceptually:

Version 1
     │
Version 2
     │
Version 3
     │
Version N

In the reference implementation, version history is stored as a list on RuntimeSession.version_history. The VersionManager provides latest, retrieve, and list_versions methods for accessing this history in a controlled manner.

Ordering reflects Runtime operational evolution.

Version History represents operational chronology rather than semantic precedence.

The ordering mechanism is implementation-independent.

7. Version Lifecycle

Conceptually, every Version follows this lifecycle:

Created
     │
Persisted
     │
Referenced
     │
Archived

The lifecycle describes observable Runtime behavior.

Persistence is not required for a Version to exist logically.

Internal implementation states remain implementation-defined.

Individual implementations may introduce additional internal states provided canonical behavior is preserved.

8. Session Restoration

Runtime may restore Runtime operational state from a previously persisted Version.

Conceptually:

Version
      │
Restore
      │
Runtime Session

Restoration creates an operational execution context equivalent to the selected Version.

Restoration shall:

preserve the original Version;
create no semantic changes;
not rewrite Version History;
not modify historical records.

A restored Session continues Runtime evolution by producing new Versions through new Transactions.

9. Relationship to Transactions

Versions originate exclusively from committed Transactions.

Rolled Back Transactions shall not create Versions.

Aborted Transactions shall not create Versions.

Every Version has exactly one originating committed Transaction.

A successful committed Transaction creates at most one Version.

10. Relationship to Storage

Version History depends upon Runtime Storage.

Storage preserves Versions.

Storage does not define Version semantics.

Version semantics are defined exclusively by this specification.

Storage provides persistence without becoming an owner of Runtime history.

Storage shall preserve:

Version identity;
Version ordering;
Version immutability.

11. Relationship to Runtime Sessions

Runtime Sessions evolve through Transactions.

Successful Transactions produce Versions.

Version History records Session operational evolution over time.

12. Relationship to CKS Core

CKS Core defines:

canonical knowledge;
semantic validity;
structural validity.

Version History preserves Runtime operational history only.

Knowledge semantics remain exclusively defined by CKS Core.

Version History records operational evolution without modifying canonical meaning.

13. Diagnostics

Runtime may produce diagnostics related to Version History.

Examples include:

restoration failure;
unavailable historical Version;
corrupted Version metadata.

Such diagnostics are Runtime Diagnostics according to SPEC-004.

Version History shall never generate, reinterpret or modify canonical diagnostics defined by CKS Core.

14. Design Principles

The Runtime Version History model follows these principles.

Immutability

Versions never change after creation.

Historical Preservation

Runtime evolution produces new Versions rather than modifying existing ones.

Deterministic Restoration

Restoring the same Version shall reconstruct equivalent Runtime operational state.

Separation of Responsibilities

Version History records Runtime evolution.

CKS Core defines knowledge semantics.

Historical Fidelity

Version History shall accurately preserve the observable sequence of Runtime evolution without altering recorded Versions.

15. Conformance

A Runtime implementation conforms to this specification when it:

creates Versions exclusively after committed Transactions;
preserves Version immutability;
records Version History for Runtime Sessions;
supports restoration from persisted Versions;
preserves separation between Runtime history and CKS Core semantics;
preserves Version History independently of the underlying persistence technology.

16. Summary

Runtime Version History defines the canonical historical model of Runtime Session evolution.

Versions are immutable snapshots of committed Runtime operational state created exclusively through successful Transaction completion.

Version History preserves Runtime evolution and enables Session restoration while leaving canonical knowledge semantics entirely under the authority of CKS Core.