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

Inherits:
Base
  • Object
show all
Extended by:
TargetRubyVersion
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 collapse

MSG = 
'Duplicate `in` pattern detected.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from TargetRubyVersion

maximum_target_ruby_version, minimum_target_ruby_version, required_maximum_ruby_version, required_minimum_ruby_version, support_target_ruby_version?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_case_match(case_node) ⇒ Object 



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# 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