Class: RuboCop::Cop::Style::NonNilCheck

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

Overview

This cop checks for non-nil checks, which are usually redundant.

Non-nil checks are allowed if they are the final nodes of predicate.

# good def signed_in? !current_user.nil? end

Examples:


# bad
if x != nil

# good (when not allowing semantic changes)
# bad (when allowing semantic changes)
if !x.nil?

# good (when allowing semantic changes)
if x

Constant Summary collapse

MSG = 
'Explicit non-nil checks are usually redundant.'
NIL_NODE = 
s(:nil)

Constants included from Util

Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, 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, #autocorrect?, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #debug?, #display_cop_names?, #exclude_file?, #include_file?, inherited, #initialize, #join_force?, lint?, #message, non_rails, qualified_cop_name, rails?, #relevant_file?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

block_length, command?, comment_line?, const_name, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_space, source_range, strip_quotes

Methods included from PathUtil

match_path?, relative_path

Constructor Details

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

Instance Method Details

#on_def(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/non_nil_check.rb', line 31

def on_def(node)
  method_name, _args, body = *node
  process_method(method_name, body)
end

#on_defs(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/non_nil_check.rb', line 36

def on_defs(node)
  _scope, method_name, _args, body = *node
  process_method(method_name, body)
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/non_nil_check.rb', line 41

def on_send(node)
  return if ignored_node?(node)
  receiver, method, args = *node

  return unless [:!=, :!].include?(method)

  if method == :!=
    add_offense(node, :selector) if args == NIL_NODE
  elsif include_semantic_changes? && method == :!
    add_offense(node, :expression) if nil_check?(receiver)
  end
end