GoogleContainerTools/skaffold · error

Unknown artifact

Error message

Unknown artifact

What it means

diagnose.typeOfArtifact panics "Unknown artifact" when an *latest.Artifact has none of the known artifact-type fields set (custom, buildpack, ko, etc.). The skaffold config schema guarantees exactly one artifact type, so a nil-everything artifact indicates a deserialization or schema bug rather than expected user input.

Source

Thrown at pkg/skaffold/diagnose/diagnose.go:124

func typeOfArtifact(a *latest.Artifact) string {
	switch {
	case a.DockerArtifact != nil:
		return "Docker artifact"
	case a.BazelArtifact != nil:
		return "Bazel artifact"
	case a.JibArtifact != nil:
		return "Jib artifact"
	case a.KanikoArtifact != nil:
		return "Kaniko artifact"
	case a.CustomArtifact != nil:
		return "Custom artifact"
	case a.BuildpackArtifact != nil:
		return "Buildpack artifact"
	case a.KoArtifact != nil:
		return "Ko artifact"
	default:
		panic("Unknown artifact")
	}
}

func timeToListDependencies(ctx context.Context, a *latest.Artifact, tag string, cfg Config) (string, []string, error) {
	start := time.Now()
	g := graph.ToArtifactGraph(cfg.Artifacts())
	sourceDependencies := graph.NewSourceDependenciesCache(cfg, nil, g)
	paths, err := sourceDependencies.SingleArtifactDependencies(ctx, a, tag)
	return timeutil.Humanize(time.Since(start)), paths, err
}

func timeToConstructSyncMap(ctx context.Context, a *latest.Artifact, cfg docker.Config) (string, error) {
	start := time.Now()
	_, err := sync.SyncMap(ctx, a, cfg)
	return timeutil.Humanize(time.Since(start)), err
}

func timeToComputeMTimes(deps []string) (string, error) {

View on GitHub (pinned to a1189de023)

Solutions

1. Ensure every artifact in skaffold.yaml sets exactly one builder type (docker, custom, buildpacks, ko, ...)
2. Validate config with `skaffold diagnose` or `skaffold config` / schema validation before building
3. If you added a new artifact type, add a case for it in typeOfArtifact
4. Check skaffold version compatibility with the skaffold.yaml apiVersion

Example fix

// before (skaffold.yaml)
artifacts:
  - image: myimg
// after
artifacts:
  - image: myimg
    docker:
      dockerfile: Dockerfile

func artifactTypeSet(a *latest.Artifact) error {
  t := a.ArtifactType
  if t == nil || (t.CustomArtifact == nil && t.BuildpackArtifact == nil && t.KoArtifact == nil && t.DockerArtifact == nil) {
    return fmt.Errorf("artifact %q has no builder type set", a.ImageName)
  }
  return nil
}

func hasKnownType(a *latest.Artifact) bool {
  return a != nil && a.ArtifactType != nil &&
    (a.ArtifactType.CustomArtifact != nil || a.ArtifactType.BuildpackArtifact != nil ||
     a.ArtifactType.KoArtifact != nil || a.ArtifactType.DockerArtifact != nil)
}

func safeTypeOf(a *latest.Artifact) (s string) {
  defer func() { if recover() != nil { s = "unknown artifact" } }()
  return typeOfArtifact(a)
}

When it happens

Trigger: CheckArtifacts calls typeOfArtifact with an Artifact produced from config where the ArtifactType union discriminated field was never set — e.g. hand-constructed structs in tests/code, or a new artifact type added to the schema but not to typeOfArtifact's switch.

Common situations: Running `skaffold diagnose` on a skaffold.yaml parsed with a newer/older schema version where a type field is dropped; a newly added builder (e.g. a new artifact kind) missing from the switch; programmatic config building that left ArtifactType nil.

Related errors

• CONFIG_UNKNOWN_API_VERSION_ERR
• the following versions are incompatible with target version
• transforming skaffold config: %w
• unsupported prefix:
• bucket name is empty

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/151c444f3eb9c5cc. Report an issue: GitHub.