Class: RuboCop::Cop::Style::FileTouch

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

Overview

Checks for usage of ‘File.open` in append mode with empty block.

Such a usage only creates a new file, but it doesn’t update timestamps for an existing file, which might have been the intention.

For example, for an existing file ‘foo.txt`:

ruby -e "puts File.mtime('foo.txt')"
# 2024-11-26 12:17:23 +0100

ruby -e "File.open('foo.txt', 'a') {}"

ruby -e "puts File.mtime('foo.txt')"
# 2024-11-26 12:17:23 +0100 -> unchanged

If the intention was to update timestamps, ‘FileUtils.touch(’foo.txt’)‘ should be used instead.

Examples:

# bad
File.open(filename, 'a') {}
File.open(filename, 'a+') {}

# good
FileUtils.touch(filename)

Constant Summary collapse

MSG = 
'Use `FileUtils.touch(%<argument>s)` instead of `File.open` in ' \
'append mode with empty block.'
RESTRICT_ON_SEND = 
%i[open].freeze
APPEND_FILE_MODES = 
%w[a a+ ab a+b at a+t].to_set.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

#file_open?(node) ⇒ Object 



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

def_node_matcher :file_open?, <<~PATTERN
  (send
    (const {nil? cbase} :File) :open
    $(...)
    (str %APPEND_FILE_MODES))
PATTERN

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/file_touch.rb', line 54

def on_send(node)
  filename = file_open?(node)
  parent = node.parent

  return unless filename
  return unless parent && empty_block?(parent)

  message = format(MSG, argument: filename.source)
  add_offense(parent, message: message) do |corrector|
    corrector.replace(parent, "FileUtils.touch(#{filename.source})")
  end
end