class RSpec::Support::MethodSignature

Extracts info about the number of arguments and allowed/required keyword args of a given method.

@private

Constants

INFINITY

Attributes

Public Class Methods

# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 16
def initialize(method)
  @method           = method
  @optional_kw_args = []
  @required_kw_args = []
  classify_parameters
end

Public Instance Methods

# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 98
def arbitrary_kw_args?
  @allows_any_kw_args
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 38
def classify_arity(arity=@method.arity)
  if arity < 0
    # `~` inverts the one's complement and gives us the
    # number of required args
    @min_non_kw_args = ~arity
    @max_non_kw_args = INFINITY
  else
    @min_non_kw_args = arity
    @max_non_kw_args = arity
  end
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 106
def classify_parameters
  optional_non_kw_args = @min_non_kw_args = 0
  @allows_any_kw_args = false

  @method.parameters.each do |(type, name)|
    case type
    # def foo(a:)
    when :keyreq  then @required_kw_args << name
    # def foo(a: 1)
    when :key     then @optional_kw_args << name
    # def foo(**kw_args)
    when :keyrest then @allows_any_kw_args = true
    # def foo(a)
    when :req     then @min_non_kw_args += 1
    # def foo(a = 1)
    when :opt     then optional_non_kw_args += 1
    # def foo(*a)
    when :rest    then optional_non_kw_args = INFINITY
    end
  end

  @max_non_kw_args = @min_non_kw_args + optional_non_kw_args
  @allowed_kw_args = @required_kw_args + @optional_kw_args
end

Without considering what the last arg is, could it contain keyword arguments?

# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 92
def could_contain_kw_args?(args)
  return false if args.count <= min_non_kw_args

  @allows_any_kw_args || @allowed_kw_args.any?
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 51
def description
  @description ||= begin
    parts = []

    unless non_kw_args_arity_description == "0"
      parts << "arity of #{non_kw_args_arity_description}"
    end

    if @optional_kw_args.any?
      parts << "optional keyword args (#{@optional_kw_args.map(&:inspect).join(", ")})"
    end

    if @required_kw_args.any?
      parts << "required keyword args (#{@required_kw_args.map(&:inspect).join(", ")})"
    end

    parts << "any additional keyword args" if @allows_any_kw_args

    parts.join(" and ")
  end
end

If the last argument is Hash, Ruby will treat only symbol keys as keyword arguments the rest will be grouped in another Hash and passed as positional argument.

# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 84
def has_kw_args_in?(args)
  Hash === args.last &&
    could_contain_kw_args?(args) &&
    (RubyFeatures.kw_arg_separation? || args.last.empty? || args.last.keys.any? { |x| x.is_a?(Symbol) })
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 77
def invalid_kw_args_from(given_kw_args)
  return [] if @allows_any_kw_args
  given_kw_args - @allowed_kw_args
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 73
def missing_kw_args_from(given_kw_args)
  @required_kw_args - given_kw_args
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 23
def non_kw_args_arity_description
  case max_non_kw_args
  when min_non_kw_args then min_non_kw_args.to_s
  when INFINITY then "#{min_non_kw_args} or more"
  else "#{min_non_kw_args} to #{max_non_kw_args}"
  end
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 102
def unlimited_args?
  @max_non_kw_args == INFINITY
end
# File rspec-support/lib/rspec/support/method_signature_verifier.rb, line 31
def valid_non_kw_args?(positional_arg_count, optional_max_arg_count=positional_arg_count)
  return true if positional_arg_count.nil?

  min_non_kw_args <= positional_arg_count &&
    optional_max_arg_count <= max_non_kw_args
end