Class: RuboCop::Cop::Lint::NonAtomicFileOperation

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/lint/non_atomic_file_operation.rb

Overview

Checks for non-atomic file operation. And then replace it with a nearly equivalent and atomic method.

These can cause problems that are difficult to reproduce, especially in cases of frequent file operations in parallel, such as test runs with parallel_rspec.

For examples: creating a directory if there is none, has the following problems

An exception occurs when the directory didn’t exist at the time of ‘exist?`, but someone else created it before `mkdir` was executed.

Subsequent processes are executed without the directory that should be there when the directory existed at the time of ‘exist?`, but someone else deleted it shortly afterwards.

Examples:

# bad - race condition with another process may result in an error in `mkdir`
unless Dir.exist?(path)
  FileUtils.mkdir(path)
end

# good - atomic and idempotent creation
FileUtils.mkdir_p(path)

# bad - race condition with another process may result in an error in `remove`
if File.exist?(path)
  FileUtils.remove(path)
end

# good - atomic and idempotent removal
FileUtils.rm_f(path)

Constant Summary collapse

MSG_REMOVE_FILE_EXIST_CHECK = 
'Remove unnecessary existence check ' \
'`%<receiver>s.%<method_name>s`.'
MSG_CHANGE_FORCE_METHOD = 
'Use atomic file operation method `FileUtils.%<method_name>s`.'
MAKE_FORCE_METHODS = 
%i[makedirs mkdir_p mkpath].freeze
MAKE_METHODS = 
%i[mkdir].freeze
REMOVE_FORCE_METHODS = 
%i[rm_f rm_rf].freeze
REMOVE_METHODS = 
%i[remove delete unlink remove_file rm rmdir safe_unlink].freeze
RECURSIVE_REMOVE_METHODS = 
%i[remove_dir remove_entry remove_entry_secure].freeze
RESTRICT_ON_SEND = 
(
  MAKE_METHODS + MAKE_FORCE_METHODS + REMOVE_METHODS + RECURSIVE_REMOVE_METHODS +
  REMOVE_FORCE_METHODS
).freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

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

#explicit_not_force?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/non_atomic_file_operation.rb', line 76

def_node_search :explicit_not_force?, <<~PATTERN
  (pair (sym :force) (:false))
PATTERN

#force?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/non_atomic_file_operation.rb', line 71

def_node_search :force?, <<~PATTERN
  (pair (sym :force) (:true))
PATTERN

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/non_atomic_file_operation.rb', line 80

def on_send(node)
  return unless if_node_child?(node)
  return if explicit_not_force?(node)
  return unless (exist_node = send_exist_node(node.parent).first)
  return unless exist_node.first_argument == node.first_argument

  register_offense(node, exist_node)
end

#receiver_and_method_name(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/non_atomic_file_operation.rb', line 66

def_node_matcher :receiver_and_method_name, <<~PATTERN
  (send (const nil? $_) $_ ...)
PATTERN

#send_exist_node(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/non_atomic_file_operation.rb', line 61

def_node_search :send_exist_node, <<~PATTERN
  $(send (const nil? {:FileTest :File :Dir :Shell}) {:exist? :exists?} ...)
PATTERN