func makeErrorMessage()

in Sources/ArgumentParser/Usage/UsageGenerator.swift [162:213]

• 50 lines of code
• 21 McCabe index (conditional complexity)

  func makeErrorMessage() -> String? {
    switch error {
    case .helpRequested, .versionRequested, .completionScriptRequested, .completionScriptCustomResponse, .dumpHelpRequested:
      return nil

    case .unsupportedShell(let shell?):
      return unsupportedShell(shell)
    case .unsupportedShell:
      return unsupportedAutodetectedShell
      
    case .notImplemented:
      return notImplementedMessage
    case .invalidState:
      return invalidState
    case .unknownOption(let o, let n):
      return unknownOptionMessage(origin: o, name: n)
    case .missingValueForOption(let o, let n):
      return missingValueForOptionMessage(origin: o, name: n)
    case .unexpectedValueForOption(let o, let n, let v):
      return unexpectedValueForOptionMessage(origin: o, name: n, value: v)
    case .unexpectedExtraValues(let v):
      return unexpectedExtraValuesMessage(values: v)
    case .duplicateExclusiveValues(previous: let previous, duplicate: let duplicate, originalInput: let arguments):
      return duplicateExclusiveValues(previous: previous, duplicate: duplicate, arguments: arguments)
    case .noValue(forKey: let k):
      return noValueMessage(key: k)
    case .unableToParseValue(let o, let n, let v, forKey: let k, originalError: let e):
      return unableToParseValueMessage(origin: o, name: n, value: v, key: k, error: e)
    case .invalidOption(let str):
      return "Invalid option: \(str)"
    case .nonAlphanumericShortOption(let c):
      return "Invalid option: -\(c)"
    case .missingSubcommand:
      return "Missing required subcommand."
    case .userValidationError(let error):
      switch error {
      case let error as LocalizedError:
        return error.errorDescription
      default:
        return String(describing: error)
      }
    case .noArguments(let error):
      switch error {
      case let error as ParserError:
        return ErrorMessageGenerator(arguments: self.arguments, error: error).makeErrorMessage()
      case let error as LocalizedError:
        return error.errorDescription
      default:
        return String(describing: error)
      }
    }
  }