ruby/NEWS.md

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NEWS for Ruby 3.3.0

This document is a list of user-visible feature changes since the 3.2.0 release, except for bug fixes.

Note that each entry is kept to a minimum, see links for details.

Language changes

Command line options

  • A new performance warning category was introduced. They are not displayed by default even in verbose mode. Turn them on with -W:performance or Warning[:performance] = true. [Feature #19538]
  • The RUBY_GC_HEAP_INIT_SLOTS environment variable has been deprecated and removed. Environment variables RUBY_GC_HEAP_%d_INIT_SLOTS should be used instead. [Feature #19785]

Core classes updates

Note: We're only listing outstanding class updates.

  • Array

    • Array#pack now raises ArgumentError for unknown directives. [Bug #19150]
  • Dir

    • Dir.for_fd added for returning a Dir object for the directory specified by the provided directory file descriptor. [Feature #19347]
    • Dir.fchdir added for changing the directory to the directory specified by the provided directory file descriptor. [Feature #19347]
    • Dir#chdir added for changing the directory to the directory specified by the provided Dir object. [Feature #19347]
  • MatchData

    • MatchData#named_captures now accepts optional symbolize_names keyword. [Feature #19591]
  • String

    • String#unpack now raises ArgumentError for unknown directives. [Bug #19150]
    • String#bytesplice now accepts new arguments index/length or range of the source string to be copied. [Feature #19314]
  • ObjectSpace::WeakKeyMap

    • New core class to build collections with weak references. The class use equality semantic to lookup keys like a regular hash, but it doesn't hold strong references on the keys. [Feature #18498]
  • Module

    • Module#set_temporary_name added for setting a temporary name for a module. [Feature #19521]
  • Process.warmup

    • Notify the Ruby virtual machine that the boot sequence is finished, and that now is a good time to optimize the application. This is useful for long running applications. The actual optimizations performed are entirely implementation specific and may change in the future without notice. [Feature #18885]
  • Refinement

    • Add Refinement#target as an alternative of Refinement#refined_class. Refinement#refined_class is deprecated and will be removed in Ruby 3.4. [Feature #19714]

Stdlib updates

The following default gems are updated.

  • RubyGems 3.5.0.dev
  • bigdecimal 3.1.4
  • bundler 2.5.0.dev
  • csv 3.2.8
  • erb 4.0.3
  • fiddle 1.1.2
  • fileutils 1.7.1
  • irb 1.8.1
  • nkf 0.1.3
  • optparse 0.4.0.pre.1
  • psych 5.1.0
  • reline 0.3.8
  • stringio 3.0.9
  • strscan 3.0.7
  • syntax_suggest 1.1.0
  • time 0.2.2
  • timeout 0.4.0
  • uri 0.12.2
  • yarp 0.11.0

The following bundled gems are updated.

  • minitest 5.20.0
  • test-unit 3.6.1
  • rexml 3.2.6
  • rss 0.3.0
  • net-imap 0.3.7
  • rbs 3.2.1
  • typeprof 0.21.8
  • debug 1.8.0

The following default gem is now bundled.

  • racc 1.7.1

See GitHub releases like Logger or changelog for details of the default gems or bundled gems.

Supported platforms

Compatibility issues

Stdlib compatibility issues

  • racc is promoted bundled gems.
    • You need to add racc to your Gemfile if you use racc under bundler environment.
  • ext/readline is retired
    • We have reline that is pure Ruby implementation compatible with ext/readline API. We rely on reline in the future. If you need to use ext/readline, you can install ext/readline via rubygems.org with gem install readline-ext.
    • We no longer need to install libraries like libreadline or libedit.

C API updates

Implementation improvements

  • defined?(@ivar) is optimized with Object Shapes.

YJIT

  • Major performance improvements over 3.2
    • Support for splat and rest arguments has been improved.
    • Registers are allocated for stack operations of the virtual machine.
    • More calls with optional arguments are compiled.
    • Exception handlers are also compiled.
    • Instance variables no longer exit to the interpreter with megamorphic Object Shapes.
    • Unsupported call types no longer exit to the interpreter.
    • Integer#!=, String#!=, Kernel#block_given?, Kernel#is_a?, Kernel#instance_of?, Module#=== are specially optimized.
    • Now more than 3x faster than the interpreter on optcarrot!
  • Metadata for compiled code uses a lot less memory.
  • Generate more compact code on ARM64
  • Option to start YJIT in paused mode and then later enable it manually
    • --yjit-pause and RubyVM::YJIT.resume
    • This can be used to enable YJIT only once your application is done booting
  • ratio_in_yjit stat produced by --yjit-stats is now avaiable in release builds, a special stats or dev build is no longer required.
  • Exit tracing option now supports sampling
    • --trace-exits-sample-rate=N
  • --yjit-stats=quiet is added to avoid printing stats on exit.
  • The default value for --yjit-exec-mem-size is changed from 64 to 128.
  • More thorough testing and multiple bug fixes

RJIT

  • Introduced a pure-Ruby JIT compiler RJIT and replaced MJIT.
    • RJIT supports only x86_64 architecture on Unix platforms.
    • Unlike MJIT, it doesn't require a C compiler at runtime.
  • RJIT exists only for experimental purposes.
    • You should keep using YJIT in production.