Class: RuboCop::Cop::Style::SafeNavigation

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/style/safe_navigation.rb

Overview

This cop transforms usages of a method call safeguarded by a non ‘nil` check for the variable whose method is being called to safe navigation (`&.`).

Examples:

# bad
foo.bar if foo
foo.bar(param1, param2) if foo
foo.bar { |e| e.something } if foo
foo.bar(param) { |e| e.something } if foo

foo.bar if !foo.nil?
foo.bar unless !foo
foo.bar unless foo.nil?

foo && foo.bar
foo && foo.bar(param1, param2)
foo && foo.bar { |e| e.something }
foo && foo.bar(param) { |e| e.something }

foo.nil? || foo.bar
!foo || foo.bar

# good
foo&.bar
foo&.bar(param1, param2)
foo&.bar { |e| e.something }
foo&.bar(param) { |e| e.something }

# Methods that `nil` will `respond_to?` should not be converted to
# use safe navigation
foo.to_i if foo

Constant Summary collapse

MSG = 
'Use safe navigation (`&.`) instead of checking if an object ' \
'exists before calling the method.'.freeze
NIL_METHODS = 
nil.methods.freeze

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 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?, #duplicate_location?, #excluded_file?, #extra_details?, #find_location, #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 Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

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, 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_distance, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, 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/safe_navigation.rb', line 86

def autocorrect(node)
  lambda do |corrector|
    if node.loc.respond_to?(:keyword) && node.loc.keyword.is?('unless')
      _variable_check, _else, method_call = *node
    else
      _variable_check, method_call = *node
    end

    if method_call.block_type?
      method, = *method_call
      corrector.insert_before(method.loc.dot, '&')
    else
      corrector.insert_before(method_call.loc.dot, '&')
    end

    corrector.remove(range(node, method_call))
  end
end

#check_node(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 77

def check_node(node)
  return if target_ruby_version < 2.3
  checked_variable, receiver, method = safe_navigation_candidate(node)
  return unless receiver == checked_variable
  return if NIL_METHODS.include?(method)
  return unless method =~ /\w+[=!?]?/
  add_offense(node, :expression)
end

#on_and(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 69

def on_and(node)
  check_node(node)
end

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 65

def on_if(node)
  check_node(node)
end

#on_or(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 73

def on_or(node)
  check_node(node)
end