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]

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]

Stdlib updates¶ ↑

The following default gems are updated.

• RubyGems 3.5.0.dev

• bigdecimal 3.1.4

• bundler 2.5.0.dev

• csv 3.2.7

• fiddle 1.1.2

• fileutils 1.7.1

• irb 1.7.0

• nkf 0.1.3

• optparse 0.4.0.pre.1

• psych 5.1.0

• reline 0.3.5

• stringio 3.0.8

• strscan 3.0.7

• syntax_suggest 1.1.0

• time 0.2.2

• timeout 0.3.2

• uri 0.12.1

The following bundled gems are updated.

• minitest 5.18.0

• test-unit 3.5.9

• rbs 3.1.0

• typeprof 0.21.7

• debug 1.8.0

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

Supported platforms¶ ↑

Compatibility issues¶ ↑

Stdlib compatibility issues¶ ↑

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¶ ↑

• Significant performance improvements over 3.2

• Splat and rest arguments support has been improved.

• Registers are allocated for stack operations of the virtual machine.

• More calls with optional arguments are compiled.

• Integer#!=, String#!=, Kernel#block_given?, Kernel#is_a?, Kernel#instance_of?, Module#=== are specially optimized.

• Instance variables no longer exit to the interpreter with megamorphic Object Shapes.

• Metadata for compiled code uses a lot less memory.

• Improved code generation 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

• Exit tracing option now supports sampling

• --trace-exits-sample-rate=N

• 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.