GoogleContainerTools/skaffold · error

yaml to json error: %w

Error message

yaml to json error: %w

What it means

ManifestList.Filter converts each YAML manifest to JSON with sigs.k8s.io/yaml (YAMLToJSON) before matching selectors. If a manifest document is not parseable YAML, the conversion fails and the error is wrapped as 'yaml to json error'. The library cannot match Group/Kind on invalid input, so it fails fast.

Source

Thrown at pkg/skaffold/kubernetes/manifest/filter.go:36

import (
	"fmt"

	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	k8syaml "sigs.k8s.io/yaml"
)

// Filter returns the manifest list that match any of the given `GroupKindSelector` items
func (l *ManifestList) Filter(selectors ...GroupKindSelector) (ManifestList, error) {
	if l == nil {
		return nil, nil
	}
	var filtered ManifestList
	for _, yByte := range *l {
		// Convert yaml byte config to unstructured.Unstructured
		jByte, err := k8syaml.YAMLToJSON(yByte)
		if err != nil {
			return nil, fmt.Errorf("yaml to json error: %w", err)
		}
		var obj unstructured.Unstructured
		if err := obj.UnmarshalJSON(jByte); err != nil {
			return nil, fmt.Errorf("unmarshaling config: %w", err)
		}
		gvk := obj.GroupVersionKind()
		for _, w := range selectors {
			if w.Matches(gvk.Group, gvk.Kind) {
				filtered.Append(yByte)
			}
		}
	}
	return filtered, nil
}

// SelectResources returns the resources defined in the manifest list that match any of the given `GroupKindSelector` items
func (l *ManifestList) SelectResources(selectors ...GroupKindSelector) ([]unstructured.Unstructured, error) {
	if l == nil {

View on GitHub (pinned to a1189de023)

Solutions

1. Run 'kubectl apply --dry-run=client' or a YAML linter (yamllint) on each manifest to find the malformed document
2. Fix the YAML syntax error reported by the wrapped %w cause (it names line/column)
3. If manifests come from another tool, re-render them and check that tool's output for corruption
4. Validate with 'skaffold render' locally before filtering in the pipeline

Example fix

// before (tab indentation -> YAML parse error)
metadata:
	name: foo
// after
metadata:
  name: foo

import "gopkg.in/yaml.v3"
func isParsableYAML(doc []byte) error {
  var v interface{}
  return yaml.Unmarshal(doc, &v)
}
// for each manifest in the list: if err := isParsableYAML(m); err != nil { fix before Filter }

func looksLikeK8sYAML(doc []byte) bool {
  var m map[string]interface{}
  if err := yaml.Unmarshal(doc, &m); err != nil || m == nil { return false }
  _, hasKind := m["kind"]
  return hasKind
}

filtered, err := manifests.Selectors(selectors).Filter(...)
if err != nil && strings.Contains(err.Error(), "yaml to json error") {
  // log wrapped cause (line/col), quarantine the bad manifest, continue
  return fmt.Errorf("manifest is not valid YAML: %w", err)
}

When it happens

Trigger: Calling ManifestList.Filter with a selector list when any element of the ManifestList contains malformed YAML (bad indentation, tabs, duplicate keys, invalid types) or non-UTF8 bytes.

Common situations: Manifests generated by templates producing broken YAML, files with tab indentation, truncated multi-document output from a previous render step, or binary/corrupted content passed as a manifest.

Related errors

• reading Kubernetes YAML: %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/dce5d35466c58797. Report an issue: GitHub.