nektos/act · error

%sExpected %s got %s

Error message

%sExpected %s got %s

What it means

Constant-match error from Node.checkString (schema.go:291): the schema declares String.Constant (a required fixed string) and the node's value differs. Used to enforce literal magic values in specific positions of the workflow schema.

Source

Thrown at pkg/schema/schema.go:291

	} else if def.AllowedValues != nil {
		s := node.Value
		for _, v := range *def.AllowedValues {
			if s == v {
				return nil
			}
		}
		return fmt.Errorf("%sExpected one of %s got %s", formatLocation(node), strings.Join(*def.AllowedValues, ","), s)
	} else if def.Null != nil {
		var myNull *byte
		return node.Decode(&myNull)
	}
	return errors.ErrUnsupported
}

func (s *Node) checkString(node *yaml.Node, def Definition) error {
	val := node.Value
	if def.String.Constant != "" && def.String.Constant != val {
		return fmt.Errorf("%sExpected %s got %s", formatLocation(node), def.String.Constant, val)
	}
	if def.String.IsExpression {
		parser := actionlint.NewExprParser()
		lexer := actionlint.NewExprLexer(val + "}}")
		exprNode, parseErr := parser.Parse(lexer)
		if parseErr != nil {
			return fmt.Errorf("%sFailed to parse: %s", formatLocation(node), parseErr.Message)
		}
		cerr := s.checkSingleExpression(exprNode)
		if cerr != nil {
			return fmt.Errorf("%s%w", formatLocation(node), cerr)
		}
	}
	return nil
}

func (s *Node) checkOneOf(def Definition, node *yaml.Node) error {
	var allErrors error

View on GitHub (pinned to 4f41128141)

Solutions

1. Set the value to the expected constant shown in the error message
2. If you intended a different construct, check the schema for the correct key/structure to use instead

Example fix

# before (schema expects the fixed keyword):
do: x-custom-action
# after:
do: x-action

Fatal validation error — set the value to the exact expected constant from the message.

When it happens

Trigger: A field where the schema pins one exact string (e.g. a discriminator key like `uses: docker://` sub-parts or a fixed `do:` keyword) receives any other value.

Common situations: Editing generated or templated workflows and changing fixed keywords; schema drift where the constant changed between act versions.

Related errors

• expressions are not allowed here
• %sFailed to parse: %s
• %sExpected a scalar got %v
• %sExpected one of %s got %s
• %sFailed to match %s: %w

AI-assisted analysis of nektos/act@4f41128141 (2026-08-15). Data as JSON: /api/errors/44c90d729cdae879. Report an issue: GitHub.