gohugoio/hugo · error

no Resource provided in transformation

Error message

no Resource provided in transformation

What it means

Thrown by resourcehelpers.ResolveArgs (tpl/internal/resourcehelpers/helpers.go:44) when a resource transformation function (e.g. js.Build, css.Sass, toCSS, minify) is called with zero arguments. Resource-transforming template functions expect the resource to transform as a piped or positional argument; with no args there is nothing to transform.

Solutions

1. Pipe the resource in: {{ $js := resources.Get "js/main.js" | js.Build }}.
2. Check the resource is non-nil before transforming: {{ with resources.Get "js/main.js" }}{{ js.Build . }}{{ end }}.
3. Verify the asset path exists under assets/ (resources.Get only looks in the asset filesystem).
4. If using positional args, pass the resource first: {{ js.Build $resource (dict "targetPath" "main.js") }}.

Example fix

// before
{{ $bundled := js.Build (dict "targetPath" "app.js") }}

// after
{{ $r := resources.Get "js/app.js" }}
{{ $bundled := js.Build $r (dict "targetPath" "app.js") }}

// Confirm the resource exists before transforming:
{{ with resources.Get "js/main.js" }}
  {{ $out := js.Build . }}
{{ end }}

// Go caller of resourcehelpers.ResolveArgs:
func isResourceTransformer(v any) bool {
    _, ok := v.(resources.ResourceTransformer)
    return ok
}

When it happens

Trigger: Calling {{ js.Build }} with nothing piped in, or {{ (resources.Get "main.js").WrongMethod }} where the pipeline produces nil and is then passed; forgetting the pipe: {{ js.Build "opts" }} where the resource was intended but omitted.

Common situations: Refactoring a pipeline and accidentally dropping the resource; resources.Get returning nil because the path was wrong, then piping nil into js.Build; misreading docs and calling the function with only an options map.

Related errors

• invalid options type
• type %T not supported in Resource transformations
• both count and seq must be provided
• cannot encode an empty string
• cannot index slice/array with nil

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/b235d147062008c2. Report an issue: GitHub.

Appendix: 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])
	}

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