Class: RuboCop::Cop::Style::ConditionalAssignment

Inherits:
Cop
  • Object
show all
Includes:
ConfigurableEnforcedStyle, IfNode, IgnoredNode, ConditionalAssignmentHelper
Defined in:
lib/rubocop/cop/style/conditional_assignment.rb

Overview

Check for `if` and `case` statements where each branch is used for assignment to the same variable when using the return of the condition can be used instead.

Examples:

EnforcedStyle: assign_to_condition

# bad
if foo
  bar = 1
else
  bar = 2
end

case foo
when 'a'
  bar += 1
else
  bar += 2
end

if foo
  some_method
  bar = 1
else
  some_other_method
  bar = 2
end

# good
bar = if foo
        1
      else
        2
      end

bar += case foo
       when 'a'
         1
       else
         2
       end

bar << if foo
         some_method
         1
       else
         some_other_method
         2
       end

EnforcedStyle: assign_inside_condition
# bad
bar = if foo
        1
      else
        2
      end

bar += case foo
       when 'a'
         1
       else
         2
       end

bar << if foo
         some_method
         1
       else
         some_other_method
         2
       end

# good
if foo
  bar = 1
else
  bar = 2
end

case foo
when 'a'
  bar += 1
else
  bar += 2
end

if foo
  some_method
  bar = 1
else
  some_other_method
  bar = 2
end

Constant Summary collapse

MSG =
'Use the return of the conditional for variable assignment ' \
'and comparison.'.freeze
ASSIGN_TO_CONDITION_MSG =
'Assign variables inside of conditionals'.freeze
VARIABLE_ASSIGNMENT_TYPES =
[:casgn, :cvasgn, :gvasgn, :ivasgn, :lvasgn].freeze
ASSIGNMENT_TYPES =
VARIABLE_ASSIGNMENT_TYPES + [:and_asgn, :or_asgn, :op_asgn].freeze
IF =
'if'.freeze
UNLESS =
'unless'.freeze
LINE_LENGTH =
'Metrics/LineLength'.freeze
INDENTATION_WIDTH =
'Style/IndentationWidth'.freeze
ENABLED =
'Enabled'.freeze
MAX =
'Max'.freeze
SINGLE_LINE_CONDITIONS_ONLY =
'SingleLineConditionsOnly'.freeze
WIDTH =
'Width'.freeze
METHODS =
[:[]=, :<<, :=~, :!~, :<=>].freeze
CONDITION_TYPES =
[:if, :case].freeze

Constants included from ConditionalAssignmentHelper

RuboCop::Cop::Style::ConditionalAssignmentHelper::ALIGN_WITH, RuboCop::Cop::Style::ConditionalAssignmentHelper::END_ALIGNMENT, RuboCop::Cop::Style::ConditionalAssignmentHelper::EQUAL, RuboCop::Cop::Style::ConditionalAssignmentHelper::KEYWORD

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from ConfigurableEnforcedStyle

#alternative_style, #ambiguous_style_detected, #correct_style_detected, #detected_style, #detected_style=, #no_acceptable_style!, #no_acceptable_style?, #opposite_style_detected, #parameter_name, #style, #style_detected, #supported_styles, #unexpected_style_detected

Methods included from ConditionalAssignmentHelper

#expand_elses, #expand_when_branches, #indent, #lhs, #tail

Methods included from IfNode

#elsif?, #if_else?, #if_node_parts, #modifier_if?, #ternary?

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?, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #reference_url, #relevant_file?, #style_guide_url, #target_ruby_version

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search_body

Methods included from Sexp

#s

Methods included from AutocorrectLogic

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

Methods included from Util

begins_its_line?, block_length, comment_line?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, to_string_literal, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object


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# File 'lib/rubocop/cop/style/conditional_assignment.rb', line 267

def autocorrect(node)
  if assignment_type?(node)
    move_assignment_inside_condition(node)
  else
    move_assignment_outside_condition(node)
  end
end

#check_assignment_to_condition(node) ⇒ Object


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# File 'lib/rubocop/cop/style/conditional_assignment.rb', line 229

def check_assignment_to_condition(node)
  ignore_node(node)

  assignment = assignment_node(node)
  return unless condition?(assignment)

  _condition, *branches, else_branch = *assignment
  return unless else_branch # empty else
  return if single_line_conditions_only? &&
            [*branches, else_branch].any?(&:begin_type?)

  add_offense(node, :expression, ASSIGN_TO_CONDITION_MSG)
end

#on_case(node) ⇒ Object


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# File 'lib/rubocop/cop/style/conditional_assignment.rb', line 256

def on_case(node)
  return unless style == :assign_to_condition
  _condition, *when_branches, else_branch = *node
  return unless else_branch # empty else

  when_branches = expand_when_branches(when_branches)
  branches = [*when_branches, else_branch]

  check_node(node, branches)
end

#on_if(node) ⇒ Object


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# File 'lib/rubocop/cop/style/conditional_assignment.rb', line 243

def on_if(node)
  return unless style == :assign_to_condition
  return if elsif?(node)

  _condition, if_branch, else_branch = *node
  elsif_branches, else_branch = expand_elses(else_branch)
  return unless else_branch # empty else

  branches = [if_branch, *elsif_branches, else_branch]

  check_node(node, branches)
end

#on_send(node) ⇒ Object


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# File 'lib/rubocop/cop/style/conditional_assignment.rb', line 222

def on_send(node)
  return unless assignment_type?(node)
  return unless style == :assign_inside_condition

  check_assignment_to_condition(node)
end