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.

With ‘IncludeSemanticChanges` set to `false` by default, this cop does not report offenses for `!x.nil?` and does no changes that might change behavior.

With ‘IncludeSemanticChanges` set to `true`, this cop reports offenses for `!x.nil?` and autocorrects that and `x != nil` to solely `x`, which is usually OK, but might change behavior.

Examples:

# bad
if x != nil
end

# good
if x
end

# Non-nil checks are allowed if they are the final nodes of predicate.
# good
def signed_in?
  !current_user.nil?
end

IncludeSemanticChanges: false (default)

# good
if !x.nil?
end

IncludeSemanticChanges: true

# bad
if !x.nil?
end

Constant Summary

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #disable_uncorrectable, #duplicate_location?, #excluded_file?, #external_dependency_checksum, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #messages, #parse, qualified_cop_name, #reason_to_not_correct, #relevant_file?, #target_rails_version, #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?, #correctable?, #disable_offense, #disable_uncorrectable?, #safe_autocorrect?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, chdir, hidden_dir?, hidden_file_in_not_hidden_dir?, match_path?, pwd, relative_path, reset_pwd, smart_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/non_nil_check.rb', line 71

def autocorrect(node)
  case node.method_name
  when :!=
    autocorrect_comparison(node)
  when :!
    autocorrect_non_nil(node, node.receiver)
  when :nil?
    autocorrect_unless_nil(node, node.receiver)
  end
end

#on_def(node) ⇒ Object Also known as: on_defs 



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# File 'lib/rubocop/cop/style/non_nil_check.rb', line 58

def on_def(node)
  body = node.body

  return unless node.predicate_method? && body

  if body.begin_type?
    ignore_node(body.children.last)
  else
    ignore_node(body)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/non_nil_check.rb', line 47

def on_send(node)
  return if ignored_node?(node)

  if not_equal_to_nil?(node)
    add_offense(node, location: :selector)
  elsif include_semantic_changes? &&
        (not_and_nil_check?(node) || unless_and_nil_check?(node))
    add_offense(node)
  end
end