argoproj/argo-workflows · error

cannot do template replacements with invalid JSON

Error message

cannot do template replacements with invalid JSON

What it means

Replace refuses to do variable substitution because the input string s failed json.Valid before any tags were processed. The template text itself is not valid JSON, so no replacement can be attempted.

Source

Thrown at util/template/replace.go:43

}

// ToAnyMap widens a string map for use with Replace. Callers that track absent optionals
// (skipped/omitted node outputs) build a map[string]any directly so nil entries survive.
func ToAnyMap(m map[string]string) map[string]any {
	anyMap := make(map[string]any, len(m))
	for k, v := range m {
		anyMap[k] = v
	}
	return anyMap
}

// Replace takes a json-formatted string and performs variable replacement. Values are raw: a nil
// entry marks an absent optional (a skipped/omitted node's output with no default), and a simple
// tag resolving to nil is a terminal error regardless of allowUnresolved, which only governs tags
// whose key is missing entirely.
func Replace(ctx context.Context, s string, replaceMap map[string]any, allowUnresolved bool) (string, error) {
	if !json.Valid([]byte(s)) {
		return "", errors.New("cannot do template replacements with invalid JSON")
	}

	t, err := NewTemplate(s)
	if err != nil {
		return "", err
	}
	replacedString, err := t.Replace(ctx, replaceMap, allowUnresolved)
	if err != nil {
		return s, err
	}

	if !json.Valid([]byte(replacedString)) {
		return s, errors.New("cannot finish template replacement because the result was invalid JSON")
	}

	return replacedString, nil
}

View on GitHub (pinned to 35bff19146)

Solutions

1. Fix the JSON syntax of the parameter/template value before substitution
2. Ensure any escaped quotes in the template survive marshalling

When it happens

Trigger: Thrown at util/template/replace.go:43 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/a5bf410486810e63. Report an issue: GitHub.