GoogleContainerTools/skaffold · error

marshaling new config: %w

Error message

marshaling new config: %w

What it means

`skaffold fix` successfully upgraded and validated the config, then tried to serialize it back to YAML with `yaml.MarshalWithSeparator`. This error wraps any failure of that marshaling step. It is rare and usually indicates an internal problem — a config value that cannot be represented in YAML (e.g. an unsupported type) rather than user error.

Source

Thrown at cmd/skaffold/app/cmd/fix.go:119

		var cfgs parser.SkaffoldConfigSet
		for _, cfg := range upgraded {
			cpCfg := latest.NewSkaffoldConfig()
			if err = util2.DeepCopy(cpCfg, cfg); err != nil {
				cpCfg = cfg
			}
			defaults.Set(cpCfg.(*latest.SkaffoldConfig))
			cfgs = append(cfgs, &parser.SkaffoldConfigEntry{
				SkaffoldConfig: cpCfg.(*latest.SkaffoldConfig),
				SourceFile:     configFile,
				IsRootConfig:   true})
		}
		if err := validation.Process(cfgs, validation.GetValidationOpts(opts)); err != nil {
			return fmt.Errorf("validating upgraded config: %w", err)
		}
	}
	newCfg, err := yaml.MarshalWithSeparator(upgraded)
	if err != nil {
		return fmt.Errorf("marshaling new config: %w", err)
	}
	if outFile != "" {
		var writeErr error
		if overwrite {
			oldCfg, readErr := os.ReadFile(configFile)
			if readErr != nil {
				return fmt.Errorf("reading config file: %w", readErr)
			}
			newFile := fmt.Sprintf("%s.v2", outFile)

			writeErr = os.WriteFile(newFile, oldCfg, 0644)
			if writeErr == nil {
				output.Default.Fprintln(out, "Backed up previous skaffold.yaml at ", newFile)
			}
		}
		if err := os.WriteFile(outFile, newCfg, 0644); err != nil {
			return fmt.Errorf("writing config file: %w", err)
		}

View on GitHub (pinned to a1189de023)

Solutions

1. Re-run `skaffold fix` — transient/marshal issues are not user-fixable state, so first confirm it reproduces.
2. Check your skaffold version and upgrade to the latest patch release; marshal bugs are fixed upstream.
3. If reproducible, reduce the config to the smallest skaffold.yaml that triggers it and file an issue.
4. As a workaround, convert the config manually: run fix without --overwrite and hand-edit the output.

// Verify skaffold and the yaml round-trip work with the current config before fixing
const check = execFileSync('skaffold', ['config', 'list'], {stdio: 'pipe'}); // ensures skaffold binary is healthy
const parsed = require('js-yaml').load(require('fs').readFileSync('skaffold.yaml', 'utf8'));
if (!parsed || typeof parsed !== 'object' || !parsed.apiVersion) throw new Error('skaffold.yaml is not a parseable skaffold config');

try {
  execFileSync('skaffold', ['fix', '--output', 'skaffold.fixed.yaml']);
} catch (e) {
  const msg = e.stderr?.toString() ?? '';
  if (msg.includes('marshaling new config')) {
    console.error('Marshal bug in skaffold fix; upgrade skaffold or convert manually.');
    // fallback: keep original config
  } else throw e;
}

When it happens

Trigger: `yaml.MarshalWithSeparator(upgraded)` returns an error, typically when the upgraded in-memory config contains a value that cannot be serialized to YAML by the yaml library.

Common situations: Practically only seen with corrupted or unusual intermediate config state, custom skaffold forks/plugins injecting non-serializable fields, or a bug in the config upgrade code.

Related errors

• marshalling configuration: %w
• validating upgraded config: %w
• invalid skaffold config: %w
• parsing skaffold config: %w
• INSPECT_PROFILE_NOT_FOUND_ERR

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/1d90a5868a9f3e5a. Report an issue: GitHub.