Class: RuboCop::Cop::Style::IfUnlessModifier

Inherits:
Cop
  • Object
show all
Includes:
RuboCop::Cop::StatementModifier
Defined in:
lib/rubocop/cop/style/if_unless_modifier.rb

Overview

Checks for if and unless statements that would fit on one line if written as a modifier if/unless. The maximum line length is configurable.

Constant Summary collapse

ASSIGNMENT_TYPES = 
[:lvasgn, :casgn, :cvasgn, :gvasgn, :ivasgn, :masgn]

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 included from RuboCop::Cop::StatementModifier

#body_has_comment?, #body_length, #comment_lines, #end_keyword_has_comment?, #fit_within_line_as_modifier_form?, #length, #max_line_length

Methods included from IfNode

#elsif?, #if_else?, #if_node_parts, #modifier_if?, #ternary_op?

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?, 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

#autocorrect(node) ⇒ Object 



57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 57

def autocorrect(node)
  cond, body, _else = if_node_parts(node)

  oneline =
    "#{body.loc.expression.source} #{node.loc.keyword.source} " +
    cond.loc.expression.source
  first_line_comment = processed_source.comments.find do |c|
    c.loc.line == node.loc.line
  end
  if first_line_comment
    oneline << ' ' << first_line_comment.loc.expression.source
  end
  oneline = "(#{oneline})" if parenthesize?(node)

  ->(corrector) { corrector.replace(node.loc.expression, oneline) }
end

#chained?(node) ⇒ Boolean

Returns:

  • (Boolean) 


30
31
32
33
34
35
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 30

def chained?(node)
  # Don't register offense for `if ... end.method`
  return false if node.parent.nil? || !node.parent.send_type?
  receiver = node.parent.children[0]
  node.equal?(receiver)
end

#message(keyword) ⇒ Object 



14
15
16
17
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 14

def message(keyword)
  "Favor modifier `#{keyword}` usage when having a single-line body." \
  ' Another good alternative is the usage of control flow `&&`/`||`.'
end

#method_uses_parens?(node, limit) ⇒ Boolean

Returns:

  • (Boolean) 


52
53
54
55
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 52

def method_uses_parens?(node, limit)
  source = node.loc.expression.source_line[0...limit.loc.column]
  source =~ /\s*\(\s*$/
end

#on_if(node) ⇒ Object 



19
20
21
22
23
24
25
26
27
28
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 19

def on_if(node)
  # discard ternary ops, if/else and modifier if/unless nodes
  return if ternary_op?(node)
  return if modifier_if?(node)
  return if elsif?(node)
  return if if_else?(node)
  return if chained?(node)
  return unless fit_within_line_as_modifier_form?(node)
  add_offense(node, :keyword, message(node.loc.keyword.source))
end

#parenthesize?(node) ⇒ Boolean

Returns:

  • (Boolean) 


37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 37

def parenthesize?(node)
  # Parenthesize corrected expression if changing to modifier-if form
  # would change the meaning of the parent expression
  # (due to the low operator precedence of modifier-if)
  return false if node.parent.nil?
  return true if ASSIGNMENT_TYPES.include?(node.parent.type)

  if node.parent.send_type?
    _receiver, _name, *args = *node.parent
    return !method_uses_parens?(node.parent, args.first)
  end

  false
end