Class: RuboCop::Cop::Style::MultilineBlockLayout

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/style/multiline_block_layout.rb

Overview

This cop checks whether the multiline do end blocks have a newline after the start of the block. Additionally, it checks whether the block arguments, if any, are on the same line as the start of the block.

Examples:

# bad
blah do |i| foo(i)
  bar(i)
end

# bad
blah do
  |i| foo(i)
  bar(i)
end

# good
blah do |i|
  foo(i)
  bar(i)
end

# bad
blah { |i| foo(i)
  bar(i)
}

# good
blah { |i|
  foo(i)
  bar(i)
}

Constant Summary collapse

MSG = 
'Block body expression is on the same line as the block start.'
ARG_MSG = 
'Block argument expression is not on the same line as the ' \
'block start.'

Constants included from Util

Util::ASGN_NODES, Util::BASIC_LITERALS, Util::EQUALS_ASGN_NODES, Util::LITERALS, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #details, #display_cop_names?, #display_style_guide?, #excluded_file?, #extra_details?, inherited, #initialize, #join_force?, lint?, match?, #message, non_rails, qualified_cop_name, rails?, #reference_url, #relevant_file?, #style_guide_url

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, directions, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#add_offense_for_expression(node, expr, msg) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 66

def add_offense_for_expression(node, expr, msg)
  expression = expr.loc.expression
  range = Parser::Source::Range.new(expression.source_buffer,
                                    expression.begin_pos,
                                    expression.end_pos)

  add_offense(node, range, msg)
end

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 75

def autocorrect(node)
  lambda do |corrector|
    _method, args, block_body = *node
    unless args.children.empty? ||
           args.loc.end.line == node.loc.begin.line
      autocorrect_arguments(corrector, node, args, block_body)
      expr_before_body = args.loc.expression.end
    end

    return unless block_body

    expr_before_body ||= node.loc.begin
    if expr_before_body.line == block_body.loc.line
      autocorrect_body(corrector, node, block_body)
    end
  end
end

#autocorrect_arguments(corrector, node, args, block_body) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 93

def autocorrect_arguments(corrector, node, args, block_body)
  end_pos = if block_body
              block_body.loc.expression.begin_pos
            else
              node.loc.end.begin.begin_pos - 1
            end
  range = Parser::Source::Range.new(args.loc.expression.source_buffer,
                                    node.loc.begin.end.begin_pos,
                                    end_pos)
  corrector.replace(range, " |#{block_arg_string(args)}|")
end

#autocorrect_body(corrector, node, block_body) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 105

def autocorrect_body(corrector, node, block_body)
  first_node = if block_body.type == :begin
                 block_body.children.first
               else
                 block_body
               end

  block_start_col = node.loc.expression.column

  corrector.insert_before(first_node.loc.expression,
                          "\n  #{' ' * block_start_col}")
end

#block_arg_string(args) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 118

def block_arg_string(args)
  args.children.map { |a| a.loc.expression.source }.join(', ')
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiline_block_layout.rb', line 43

def on_block(node)
  end_loc = node.loc.end
  do_loc = node.loc.begin # Actually it's either do or {.
  return if do_loc.line == end_loc.line # One-liner, no newline needed.

  # A block node has three children: the block start,
  # the arguments, and the expression. We care if the block start
  # with arguments and the expression start on the same line.
  _block_start, args, last_expression = node.children

  unless args.children.empty?
    line = args.loc.end.nil? ? args.loc.line : args.loc.end.line
    if do_loc.line != line
      add_offense_for_expression(node, args, ARG_MSG)
    end
  end

  return unless last_expression
  expression_loc = last_expression.loc
  return unless do_loc.line == expression_loc.line
  add_offense_for_expression(node, last_expression, MSG)
end