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¶ ↑

• RubyGems and Bundler warn if users require gem that is scheduled to become the bundled gems in the future version of Ruby. [Feature #19351] [Feature #19776] [Feature #19843]

• Random::Formatter#alphanumeric is extended to accept optional chars keyword argument. [Feature #18183]

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.