private static String getErrorMessage(String clusterName, Schema schema, String unsupportedFields) {
        return String.format("For cluster '%s', search '%s': The following complex fields do not support using struct field attributes: %s. " +
                             "Only supported for the following complex field types: array or map of struct with primitive types, map of primitive types. " +
                             "The supported primitive types are: byte, int, long, float, double and string",
                             clusterName, schema.getName(), unsupportedFields);
    }
Validates that complex fields (of type struct or map) that have struct field attributes are supported.

Only applies for indexed search clusters.

@author geirst
config-model/src/main/java/com/yahoo/vespa/model/application/validation/ComplexFieldsWithStructFieldAttributesValidator.java