GoogleContainerTools/skaffold · error

reading Kubernetes YAML: %w

Error message

reading Kubernetes YAML: %w

What it means

SetNamespace unmarshals each manifest item into a generic map (map[string]interface{}) with gopkg.in/yaml.v3 before conditionally adding the namespace. If a manifest is not valid YAML, yaml.Unmarshal fails and the error is wrapped as 'reading Kubernetes YAML'.

Source

Thrown at pkg/skaffold/kubernetes/manifest/namespaces.go:98

		if ns := strings.TrimSpace(nsString); ns != "" {
			r.namespaces[ns] = true
		}
	}
	return false
}

// SetNamespace sets labels to a list of Kubernetes manifests if they are not set.
// Returns error if any manifest in the list has namespace set.
func (l *ManifestList) SetNamespace(namespace string, rs ResourceSelector) (ManifestList, error) {
	if namespace == "" {
		namespace = defaultNamespace
	}
	var updated ManifestList
	for _, item := range *l {
		updatedManifest := item
		m := make(map[string]interface{})
		if err := yaml.Unmarshal(item, &m); err != nil {
			return nil, fmt.Errorf("reading Kubernetes YAML: %w", err)
		}
		if shouldTransformManifest(m, rs) {
			var errU error
			if errU = addOrUpdateNamespace(m, namespace); errU != nil {
				return nil, errU
			}
			updatedManifest, errU = yaml.Marshal(m)
			if errU != nil {
				return nil, nsSettingErr(errU)
			}
		}
		updated = append(updated, updatedManifest)
	}

	log.Entry(context.TODO()).Debugln("manifests set with namespace", updated.String())
	return updated, nil
}

View on GitHub (pinned to a1189de023)

Solutions

1. Fix the YAML syntax error named in the wrapped cause (yaml.v3 reports line/column)
2. Ensure each document is a top-level mapping (object), not a list or scalar
3. Run a YAML parser/linter over each manifest to catch the offending file before transformation
4. Regenerate the manifest list from the render step and confirm its output parses

Example fix

// before: top-level list cannot unmarshal into map[string]interface{}
- apiVersion: v1
  kind: Service
// after
apiVersion: v1
kind: Service

import "gopkg.in/yaml.v3"
func isYAMLMap(item []byte) error {
  var m map[string]interface{}
  if err := yaml.Unmarshal(item, &m); err != nil { return err }
  if m == nil { return errors.New("empty or non-mapping document") }
  return nil
}
// check each item before SetNamespace

func isDocMapping(item []byte) bool {
  var m map[string]interface{}
  return yaml.Unmarshal(item, &m) == nil && m != nil
}

updated, err := manifests.Transform(rs, transform.SetNamespace(ns))
if err != nil && strings.Contains(err.Error(), "reading Kubernetes YAML") {
  // find the malformed item, fix or drop it, then retry the transform
  return fmt.Errorf("manifest unreadable as YAML: %w", err)
}

When it happens

Trigger: Calling ManifestList.SetNamespace (via BaseTransform) when any item in the ManifestList is malformed YAML — syntax errors, or content that cannot unmarshal into a map (e.g. a top-level sequence or scalar).

Common situations: Templates or Helm output producing invalid YAML, manifests whose top level is a list instead of an object, files with duplicate keys or bad types (e.g. 'replicas: abc' where the map decode is fine but downstream steps then fail).

Related errors

• yaml to json error: %w
• loading post-renderer result: %w
• loading manifests: %w
• DEPLOY_READ_MANIFEST_ERR
• parsing manifests file into manifest list object: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/a998a9ea38cd5f0e. Report an issue: GitHub.