hasura/graphql-engine · error

convert to yaml: %w

Error message

convert to yaml: %w

What it means

StoreManifest serializes a Plugin struct to YAML before writing the plugin receipt file; this error means yaml.Marshal failed. With a plain data struct this is rare, and usually indicates a field type the YAML encoder cannot handle (e.g. custom types with broken MarshalYAML, channels, funcs, or cyclic references).

Source

Thrown at cli/plugins/plugins.go:476

}

func (c *Config) LoadManifest(path string) (Plugin, error) {
	var op errors.Op = "plugins.Config.LoadManifest"

	plugin, err := c.ReadPluginFromFile(path)
	if err != nil {
		return plugin, errors.E(op, err)
	}

	return plugin, nil
}

func (c *Config) StoreManifest(plugin Plugin, dest string) error {
	var op errors.Op = "plugins.Config.StoreManifest"

	yamlBytes, err := yaml.Marshal(plugin)
	if err != nil {
		return errors.E(op, fmt.Errorf("convert to yaml: %w", err))
	}

	err = os.WriteFile(dest, yamlBytes, 0o644)
	if err != nil {
		return errors.E(op, fmt.Errorf("write plugin receipt %q: %w", dest, err))
	}

	return nil
}

View on GitHub (pinned to 724551b9ae)

Solutions

1. Inspect the Plugin struct for custom MarshalYAML methods or non-serializable field types (func, chan, complex) and fix them
2. Check for cyclic references between Plugin and nested structs
3. Unit-test yaml.Marshal on the exact Plugin value being stored to reproduce the encoder error

Example fix

// before
type Plugin struct {
	Hooks chan Hook // yaml cannot marshal channels
}

// after
type Plugin struct {
	Hooks []Hook
}

if _, err := yaml.Marshal(plugin); err != nil { return fmt.Errorf("plugin not serializable: %w", err) }

if err := cfg.StoreManifest(plugin, dest); err != nil {
	if strings.Contains(err.Error(), "convert to yaml") {
		// fix Plugin struct fields; do not retry
	}
}

When it happens

Trigger: Calling Config.Install or Config.Upgrade with a Plugin whose fields include a type implementing yaml.Marshaler that itself returns an error, or a cyclic data structure.

Common situations: Custom plugin structs with map[interface{}]interface{} keys that are not marshalable; a fork or version change that added non-serializable fields to Plugin; NaN/Inf values in unsupported key positions.

Related errors

• unable to marshal run_sql args in %s: %w
• error in marshalling common: %w
• error in marshalling actions, custom_types from metadata: %w
• error in marshaling common: %w
• error in executing pre-response plugins, unable to encode re

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/16a1d55f5c4a07f6. Report an issue: GitHub.