class RuboCop::Cop::Layout::CaseIndentation

This cop checks how the *when*s of a case expression are indented in relation to its case or end keyword.

It will register a separate offense for each misaligned when.

@example

# If Layout/EndAlignment is set to keyword style (default)
# *case* and *end* should always be aligned to same depth,
# and therefore *when* should always be aligned to both -
# regardless of configuration.

# bad for all styles
case n
  when 0
    x * 2
  else
    y / 3
end

# good for all styles
case n
when 0
  x * 2
else
  y / 3
end

@example

# if EndAlignment is set to other style such as
# start_of_line (as shown below), then *when* alignment
# configuration does have an effect.

# EnforcedStyle: case (default)

# bad
a = case n
when 0
  x * 2
else
  y / 3
end

# good
a = case n
    when 0
      x * 2
    else
      y / 3
end

# EnforcedStyle: end

# bad
a = case n
    when 0
      x * 2
    else
      y / 3
end

# good
a = case n
when 0
  x * 2
else
  y / 3
end

Constants

MSG

Public Instance Methods

on_case(case_node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 78
def on_case(case_node)
  return if case_node.single_line?

  case_node.each_when do |when_node|
    check_when(when_node)
  end
end

Private Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 133
def autocorrect(node)
  whitespace = whitespace_range(node)

  return false unless whitespace.source.strip.empty?

  lambda do |corrector|
    corrector.replace(whitespace, replacement(node))
  end
end
base_column(case_node, base) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 126
def base_column(case_node, base)
  case base
  when :case then case_node.location.keyword.column
  when :end  then case_node.location.end.column
  end
end
check_when(when_node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 88
def check_when(when_node)
  when_column = when_node.loc.keyword.column
  base_column = base_column(when_node.parent, style)

  if when_column == base_column + indentation_width
    correct_style_detected
  else
    incorrect_style(when_node)
  end
end
incorrect_style(when_node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 107
def incorrect_style(when_node)
  when_column = when_node.loc.keyword.column
  base_column = base_column(when_node.parent, alternative_style)

  add_offense(when_node, location: :keyword, message: message(style)) do
    if when_column == base_column
      opposite_style_detected
    else
      unrecognized_style_detected
    end
  end
end
indent_one_step?() click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 99
def indent_one_step?
  cop_config['IndentOneStep']
end
indentation_width() click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 103
def indentation_width
  indent_one_step? ? configured_indentation_width : 0
end
message(base) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 120
def message(base)
  depth = indent_one_step? ? 'one step more than' : 'as deep as'

  format(MSG, depth, base)
end
replacement(node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 150
def replacement(node)
  case_node = node.each_ancestor(:case).first
  base_type = cop_config[style_parameter_name] == 'end' ? :end : :case

  column = base_column(case_node, base_type)
  column += indentation_width

  ' ' * column
end
whitespace_range(node) click to toggle source
# File lib/rubocop/cop/layout/case_indentation.rb, line 143
def whitespace_range(node)
  when_column = node.location.keyword.column
  begin_pos = node.loc.keyword.begin_pos

  range_between(begin_pos - when_column, begin_pos)
end