gohugoio/hugo · error

requires at least 2 arguments

Error message

requires at least 2 arguments

What it means

Thrown by strings.ReplacePairs when fewer than 2 arguments are supplied. ReplacePairs needs at least a replacement spec (slice or one pair) and the source string; the last arg is always the source.

Solutions

1. Provide at least 2 arguments ending with the source string.
2. Use the slice form: strings.ReplacePairs (slice "a" "b") $s.
3. Use the inline form: strings.ReplacePairs "a" "b" $s.
4. Count arguments in the template call.

Example fix

// before:
{{ strings.ReplacePairs $s }}
// after (inline pair + source):
{{ strings.ReplacePairs "a" "b" $s }}

{{ if ge (len $args) 2 }}{{ strings.ReplacePairs $args... }}{{ else }}{{ warnf "ReplacePairs needs >=2 args" }}{{ end }}

When it happens

Trigger: Calling {{ strings.ReplacePairs }} or {{ strings.ReplacePairs $s }} with zero or one argument. Both forms (inline pairs or slice) require the source string as the last positional argument.

Common situations: Forgetting the source string, calling with no args by mistake, or assuming ReplacePairs takes a map argument as a single value.

Related errors

• uneven number of replacement pairs
• Defer does not take any arguments
• end argument must be integer
• failed to convert content to string
• failed to convert s to string

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/0eeb5a114e22f537. Report an issue: GitHub.

Appendix: source

Thrown at tpl/strings/strings.go:265

	if len(limit) == 0 {
		return strings.ReplaceAll(ss, so, sn), nil
	}

	lim, err := cast.ToIntE(limit[0])
	if err != nil {
		return "", err
	}

	return strings.Replace(ss, so, sn, lim), nil
}

// ReplacePairs returns a copy of a string with multiple replacements performed
// in a single pass. The last argument is the source string. Preceding arguments
// are old/new string pairs, either as a slice or as individual arguments.
func (ns *Namespace) ReplacePairs(args ...any) (string, error) {
	if len(args) < 2 {
		return "", fmt.Errorf("requires at least 2 arguments")
	}

	ss, err := cast.ToStringE(args[len(args)-1])
	if err != nil {
		return "", err
	}

	var p []string
	if len(args) == 2 {
		// slice form: ReplacePairs (slice "a" "b") "s"
		if !hreflect.IsSlice(args[0]) {
			return "", fmt.Errorf("with 2 arguments, the first must be a slice of replacement pairs, got %T", args[0])
		}
		p, err = cast.ToStringSliceE(args[0])
		if err != nil {
			return "", err
		}
	}

View on GitHub (pinned to 52c9bd7908)