gohugoio/hugo · error

no Resource provided in transformation

Error message

no Resource provided in transformation

What it means

ResolveArgs backs Hugo's resource-transformation template functions (resources.Minify, resources.Fingerprint, resources.PostCSS, resources.Babel, etc.), which accept `(resource)` or `(options, resource)` to support both call and pipeline styles. With zero args there is no resource to transform, so Hugo errors immediately. The same message is also reused at line 58 when two args are given but the second is neither a ResourceTransformer nor an options map.

Source

Thrown at tpl/internal/resourcehelpers/helpers.go:44

// We allow string or a map as the first argument in some cases.
func ResolveIfFirstArgIsString(args []any) (resources.ResourceTransformer, string, bool) {
	if len(args) != 2 {
		return nil, "", false
	}

	v1, ok1 := args[0].(string)
	if !ok1 {
		return nil, "", false
	}
	v2, ok2 := args[1].(resources.ResourceTransformer)

	return v2, v1, ok2
}

// This roundabout way of doing it is needed to get both pipeline behavior and options as arguments.
func ResolveArgs(args []any) (resources.ResourceTransformer, map[string]any, error) {
	if len(args) == 0 {
		return nil, nil, errors.New("no Resource provided in transformation")
	}

	if len(args) == 1 {
		r, ok := args[0].(resources.ResourceTransformer)
		if !ok {
			return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
		}
		return r, nil, nil
	}

	r, ok := args[1].(resources.ResourceTransformer)
	if !ok {
		if _, ok := args[1].(map[string]any); !ok {
			return nil, nil, fmt.Errorf("no Resource provided in transformation")
		}
		return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
	}

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Ensure the resource exists and is passed: `{{ $css := resources.Get "css/main.css" }}{{ with $css }}{{ .| minify }}{{ end }}`.
2. Guard against nil from resources.Get with `with` or an explicit errorf.
3. In pipelines, options come first: `$r | resources.PostCSS $opts` is `PostCSS $opts $r`.

Example fix

<!-- before -->
{{ $css := resources.Get "css/mian.css" | minify }}
<!-- after -->
{{ $css := resources.Get "css/main.css" }}
{{ with $css }}{{ $min := . | minify }}{{ end }}

{{ $img := resources.Get "logo.png" }}
{{ if $img }}{{ $small := $img.Resize "200x" }}{{ else }}{{ warnf "logo.png not found" }}{{ end }}

When it happens

Trigger: Calling a transform with no arguments: `{{ resources.Minify }}`, or a broken pipeline where the piped resource evaluates to nothing; two-arg calls where the second argument is not a resource or map.

Common situations: `resources.Get` returned nil (missing asset file) and the nil was piped into Minify/Fingerprint; partial refactors that dropped the resource argument; wrong pipe order putting options last.

Related errors

• type %T not supported in Resource transformations
• invalid options type: %w
• no Key set in Resource
• resources.PostProcess cannot be used in a deferred template
• must not provide more arguments than Resource and hash algor

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/b235d147062008c2.json. Report an issue: GitHub ↗.