class RuboCop::Cop::Style::MissingElse

Checks for ‘if` expressions that do not have an `else` branch.

NOTE: Pattern matching is allowed to have no ‘else` branch because unlike `if` and `case`, it raises `NoMatchingPatternError` if the pattern doesn’t match and without having ‘else`.

Supported styles are: if, case, both.

@example EnforcedStyle: both (default)

# warn when an `if` or `case` expression is missing an `else` branch.

# bad
if condition
  statement
end

# bad
case var
when condition
  statement
end

# good
if condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

# good
case var
when condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

@example EnforcedStyle: if

# warn when an `if` expression is missing an `else` branch.

# bad
if condition
  statement
end

# good
if condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

# good
case var
when condition
  statement
end

# good
case var
when condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

@example EnforcedStyle: case

# warn when a `case` expression is missing an `else` branch.

# bad
case var
when condition
  statement
end

# good
case var
when condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

# good
if condition
  statement
end

# good
if condition
  statement
else
  # the content of `else` branch will be determined by Style/EmptyElse
end

Constants

MSG
MSG_EMPTY
MSG_NIL

Public Instance Methods

on_case(node) click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 115
def on_case(node)
  return if if_style?

  check(node)
end
on_case_match(node) click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 121
def on_case_match(node)
  # do nothing.
end
on_normal_if_unless(node) click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 108
def on_normal_if_unless(node)
  return if case_style?
  return if unless_else_cop_enabled? && node.unless?

  check(node)
end

Private Instance Methods

autocorrect(corrector, node) click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 146
def autocorrect(corrector, node)
  case empty_else_style
  when :empty
    corrector.insert_before(node.loc.end, 'else; nil; ')
  when :nil
    corrector.insert_before(node.loc.end, 'else; ')
  end
end
case_style?() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 159
def case_style?
  style == :case
end
check(node) click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 127
def check(node)
  return if node.else?

  add_offense(node, message: format(message_template, type: node.type)) do |corrector|
    autocorrect(corrector, node)
  end
end
empty_else_config() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 177
def empty_else_config
  config.for_cop('Style/EmptyElse')
end
empty_else_style() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 171
def empty_else_style
  return unless empty_else_config.key?('EnforcedStyle')

  empty_else_config['EnforcedStyle'].to_sym
end
if_style?() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 155
def if_style?
  style == :if
end
message_template() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 135
def message_template
  case empty_else_style
  when :empty
    MSG_NIL
  when :nil
    MSG_EMPTY
  else
    MSG
  end
end
unless_else_config() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 167
def unless_else_config
  config.for_cop('Style/UnlessElse')
end
unless_else_cop_enabled?() click to toggle source
# File lib/rubocop/cop/style/missing_else.rb, line 163
def unless_else_cop_enabled?
  unless_else_config.fetch('Enabled')
end