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Class: RuboCop::Cop::Lint::DuplicateMatchPattern

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

Overview

Checks that there are no repeated patterns used in in keywords.

Examples:

# bad
case x
in 'first'
  do_something
in 'first'
  do_something_else
end

# good
case x
in 'first'
  do_something
in 'second'
  do_something_else
end

# bad - repeated alternate patterns with the same conditions don't depend on the order
case x
in foo | bar
  first_method
in bar | foo
  second_method
end

# good
case x
in foo | bar
  first_method
in bar | baz
  second_method
end

# bad - repeated hash patterns with the same conditions don't depend on the order
case x
in foo: a, bar: b
  first_method
in bar: b, foo: a
  second_method
end

# good
case x
in foo: a, bar: b
  first_method
in bar: b, baz: c
  second_method
end

# bad - repeated array patterns with elements in the same order
case x
in [foo, bar]
  first_method
in [foo, bar]
  second_method
end

# good
case x
in [foo, bar]
  first_method
in [bar, foo]
  second_method
end

# bad - repeated the same patterns and guard conditions
case x
in foo if bar
  first_method
in foo if bar
  second_method
end

# good
case x
in foo if bar
  first_method
in foo if baz
  second_method
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::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.

.builtin?

Class Method Summary

::RuboCop::Cop::TargetRubyVersion - Extended

::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

Cops (other than builtin) are encouraged to implement this.

.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::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, #use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#on_case_match(case_node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/duplicate_match_pattern.rb', line 97

def on_case_match(case_node)
  case_node.in_pattern_branches.each_with_object(Set.new) do |in_pattern_node, previous|
    pattern = in_pattern_node.pattern
    next if previous.add?(pattern_identity(pattern))

    add_offense(pattern)
  end
end

#pattern_identity(pattern) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/duplicate_match_pattern.rb', line 108

def pattern_identity(pattern)
  pattern_source = if pattern.hash_pattern_type? || pattern.match_alt_type?
                     pattern.children.map(&:source).sort.to_s
                   else
                     pattern.source
                   end

  return pattern_source unless (guard = pattern.parent.children[1])

  pattern_source + guard.source
end