return OUTPUT_DIRECTORY_VALIDATOR;
            default:
                throw new AssertionError("Unknown tree type " + spec);
        }
    }

    private static final String INPUT_FILE_DOES_NOT_EXIST = "INPUT_FILE_DOES_NOT_EXIST";

    private static void reportMissingInput(PropertyValidationContext context, String kind, String propertyName, File input) {
        context.visitPropertyProblem(problem -> {

Possible solutions:
  1. Make sure the file exists before the task is called.
  2. Make sure that the task which produces the file is declared as an input.

${validationMessage("input_file_does_not_exist")}
"""

        render inputDoesNotExist {
            property('prop')
            dir(location)
            includeLink()
        }

        then:
        outputEquals """

[[input_file_does_not_exist]]
== Input file doesn't exist

This error occurs whenever a file (or a directory) is declared as an input of a task, but at the moment the task is executed, the file (or directory) doesn't exist.

    }

    String inputDoesNotExist(@DelegatesTo(value = IncorrectInputMessage, strategy = Closure.DELEGATE_FIRST) Closure<?> spec = {}) {
        def config = display(IncorrectInputMessage, 'input_file_does_not_exist', spec)
        config.description("specifies ${config.kind} '${config.file}' which doesn't exist")
            .reason("An input file was expected to be present but it doesn't exist")