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

Inherits:
Cop
  • Object
show all
Extended by:
TargetRubyVersion
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 (`&.`).

Configuration option: ConvertCodeThatCanStartToReturnNil The default for this is ‘false`. When configured to `true`, this will check for code in the format `!foo.nil? && foo.bar`. As it is written, the return of this code is limited to `false` and whatever the return of the method is. If this is converted to safe navigation, `foo&.bar` can start returning `nil` as well as what the method returns.

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 }

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

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

# 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::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, 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 TargetRubyVersion

minimum_target_ruby_version, support_target_ruby_version?

Methods inherited from Cop

#add_offense, all, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_ruby_version

Methods included from AST::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?, compatible_external_encoding_for?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, hard_to_type?, 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_supported_styles, 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

#allowed_if_condition?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 100

def allowed_if_condition?(node)
  node.if_type? && (node.else? || node.elsif?)
end

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 113

def autocorrect(node)
  if node.if_type?
    _check, body, = *node.node_parts
  else
    _check, body = *node
  end

  method_call, = *body if body.block_type?

  lambda do |corrector|
    corrector.remove(begin_range(node, body))
    corrector.remove(end_range(node, body))
    corrector.insert_before((method_call || body).loc.dot, '&')
  end
end

#check_node(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 89

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

  add_offense(node, :expression)
end

#extract_parts(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 104

def extract_parts(node)
  if cop_config['ConvertCodeThatCanStartToReturnNil']
    safe_navigation_candidate(node) ||
      candidate_that_may_introduce_nil(node)
  else
    safe_navigation_candidate(node)
  end
end

#on_and(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 81

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 75

def on_if(node)
  return if node.ternary?

  check_node(node)
end

#on_or(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/safe_navigation.rb', line 85

def on_or(node)
  check_node(node)
end