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Class: RuboCop::Cop::Style::EmptyCaseCondition

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/empty_case_condition.rb

Overview

Checks for case statements with an empty condition.

Examples:

# bad:
case
when x == 0
  puts 'x is 0'
when y == 0
  puts 'y is 0'
else
  puts 'neither is 0'
end

# good:
if x == 0
  puts 'x is 0'
elsif y == 0
  puts 'y is 0'
else
  puts 'neither is 0'
end

# good: (the case condition node is not empty)
case n
when 0
  puts 'zero'
when 1
  puts 'one'
else
  puts 'more'
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::RangeHelp - Included

BYTE_ORDER_MARK, NOT_GIVEN

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::RangeHelp - Included

#add_range, #column_offset_between,
#contents_range

A range containing only the contents of a literal with delimiters (e.g.

#directions,
#effective_column

Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.

#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#autocorrect(corrector, case_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 63

def autocorrect(corrector, case_node)
  when_branches = case_node.when_branches

  correct_case_when(corrector, case_node, when_branches)
  correct_when_conditions(corrector, when_branches)
end

#correct_case_when(corrector, case_node, when_nodes) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 70

def correct_case_when(corrector, case_node, when_nodes)
  case_range = case_node.loc.keyword.join(when_nodes.first.loc.keyword)

  corrector.replace(case_range, 'if')

  keep_first_when_comment(case_range, corrector)

  when_nodes[1..].each do |when_node|
    corrector.replace(when_node.loc.keyword, 'elsif')
  end
end

#correct_when_conditions(corrector, when_nodes) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 82

def correct_when_conditions(corrector, when_nodes)
  when_nodes.each do |when_node|
    conditions = when_node.conditions

    replace_then_with_line_break(corrector, conditions, when_node)

    next unless conditions.size > 1

    range = range_between(conditions.first.source_range.begin_pos,
                          conditions.last.source_range.end_pos)

    corrector.replace(range, conditions.map(&:source).join(' || '))
  end
end

#keep_first_when_comment(case_range, corrector) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 97

def keep_first_when_comment(case_range, corrector)
  indent = ' ' * case_range.column
  comments = processed_source.each_comment_in_lines(
    case_range.first_line...case_range.last_line
  ).map { |comment| "#{indent}#{comment.text}\n" }.join

  line_beginning = case_range.adjust(begin_pos: -case_range.column)
  corrector.insert_before(line_beginning, comments)
end

#on_case(case_node)

Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 46

def on_case(case_node)
  if case_node.condition || NOT_SUPPORTED_PARENT_TYPES.include?(case_node.parent&.type)
    return
  end

  branch_bodies = [*case_node.when_branches.map(&:body), case_node.else_branch].compact

  return if branch_bodies.any? do |body|
    body.return_type? || body.each_descendant.any?(&:return_type?)
  end

  add_offense(case_node.loc.keyword) { |corrector| autocorrect(corrector, case_node) }
end

#replace_then_with_line_break(corrector, conditions, when_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/empty_case_condition.rb', line 107

def replace_then_with_line_break(corrector, conditions, when_node)
  return unless when_node.parent.parent && when_node.then?

  range = range_between(conditions.last.source_range.end_pos, when_node.loc.begin.end_pos)

  corrector.replace(range, "\n")
end