Class: RuboCop::Cop::Lint::IncompatibleIoSelectWithFiberScheduler

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

Overview

Checks for IO.select that is incompatible with Fiber Scheduler since Ruby 3.0.

When an array of IO objects waiting for an exception (the third argument of IO.select) is used as an argument, there is no alternative API, so offenses are not registered.

Note
 When the method is successful the return value of IO.select is , and the return value of io.wait_readable and io.wait_writable are self. They are not autocorrected when assigning a return value because these types are different. It’s up to user how to handle the return value.

Examples:


# bad
IO.select([io], [], [], timeout)

# good
io.wait_readable(timeout)

# bad
IO.select([], [io], [], timeout)

# good
io.wait_writable(timeout)

Cop Safety Information:

  • This cop’s autocorrection is unsafe because NoMethodError occurs if require 'io/wait' is not called.

Constant Summary collapse

MSG = 
'Use `%<preferred>s` instead of `%<current>s`.'
RESTRICT_ON_SEND = 
%i[select].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, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #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, #ready, #relevant_file?, 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

#io_select(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/incompatible_io_select_with_fiber_scheduler.rb', line 41

def_node_matcher :io_select, <<~PATTERN
  (send
    (const {nil? cbase} :IO) :select $...)
PATTERN

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/incompatible_io_select_with_fiber_scheduler.rb', line 46

def on_send(node)
  read, write, excepts, timeout = *io_select(node)
  return if excepts && !excepts.children.empty?
  return unless scheduler_compatible?(read, write) || scheduler_compatible?(write, read)

  preferred = preferred_method(read, write, timeout)
  message = format(MSG, preferred: preferred, current: node.source)

  add_offense(node, message: message) do |corrector|
    next if node.parent&.assignment?

    corrector.replace(node, preferred)
  end
end