0062: Artifact result alternatives

Status: accepted for the 0.7 development SDK.

Decision

Artifact reasons and reproducibility issues carry one closed alternative. Each case contains its applicable identities, counts, path or fingerprint evidence; unrelated fields cannot be independently attached to it. Rust retains its enums, C uses checked projections, C++ variants and Python frozen records with union annotations. Required unknown kinds fail explicitly.

These are copied observations, not authority or requests to change knowledge. Construction checks payload constraints; operations still establish existence and production scope. Optional fingerprint evidence remains optional within the cases that support it. Bounded paths and opaque fingerprint bytes retain their meaning and ownership.

Public values and standards impact

Use the case type to inspect its payload. Python reproducibility issues expose their derived kind for display and use isinstance to narrow a payload. The issue alternatives are ReproducibilityProducerMissing, ReproducibilityProducerAmbiguous, ReproducibilityToolMissing, ReproducibilityParametersMissing or ReproducibilityInputMissing. C++ uses a std::variant of those case types; inspect it with std::get_if. artifactReproducibilityIssueKind returns its display category. Ambiguous producer counts use ReproducibilityProducerAmbiguous::create and activityCount(); the other cases are ordinary aggregates of applicable IDs. Python artifact reasons return the matching Artifact… record; isinstance(reason, ArtifactFingerprintChanged) exposes required old/current bytes and their domain. Dependency-path changes carry the direct input and captured path, without a fabricated zero subject ID. Unrelated constructor arguments are rejected. The display kind derives from the case type. C++ ArtifactReasonValue::create checks a payload variant and exposes it through a const value() view; copied values own their paths and evidence. ArtifactReason is that checked value; kind() is its derived display tag. Moved sources support destruction or reassignment. Input case records remain unvalidated until the factory accepts them. In C ABI 50, a category read precedes payload access with that expected kind. Wrong-kind access returns InvalidArgument and a zero record. Borrowed strings, paths and byte spans last until their evaluation/report handle is released.

No schema, persisted identity or external standards mapping changes. These projections preserve the existing recorded provenance and dependency semantics.