[ruby-core:115686] Ruby 3.3.0-rc1 Released"

We are pleased to announce the release of Ruby 3.3.0-rc1. Ruby 3.3
adds a new parser named Prism, uses Lrama as a parser generator, adds
a new pure-Ruby JIT compiler named RJIT, and many performance
improvements especially YJIT.

After the release of RC1, we will avoid introducing ABI
incompatibilities wherever possible. If we need to do, we'll announce
it in the release note.

## Prism

* Introduced [the Prism parser](https://github.com/ruby/prism) as a default gem
    * Prism is a portable, error tolerant, and maintainable recursive
descent parser for the Ruby language
* Prism is production ready and actively maintained, you can use it in
place of Ripper
    * There is [extensive
documentation](https://ruby.github.io/prism/) on how to use Prism
    * Prism is both a C library that will be used internally by CRuby
and a Ruby gem that can be used by any tooling which needs to parse
Ruby code
    * Notable methods in the Prism API are:
        * `Prism.parse(source)` which returns the AST as part of a ParseResult
        * `Prism.dump(source, filepath)` which returns the serialized
AST as a String
        * `Prism.parse_comments(source)` which returns the comments
* You can make pull requests or issues directly on [the Prism
repository](https://github.com/ruby/prism) if you are interested in
contributing

## Use Lrama instead of Bison

* Replace Bison with [Lrama LALR parser
generator](https://github.com/ruby/lrama) [Feature
#19637](https://bugs.ruby-lang.org/issues/19637)
  * If you have interest, please see [The future vision of Ruby
Parser](https://rubykaigi.org/2023/presentations/spikeolaf.html)
  * Lrama internal parser is replaced with LR parser generated by Racc
for maintainability
  * Parameterizing Rules `(?, *, +)` are supported, it will be used in
Ruby parse.y

## 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.
* If you are interested in developing JIT for Ruby, please check out
[k0kubun's presentation on Day 3 of
RubyKaigi](https://rubykaigi.org/2023/presentations/k0kubun.html#day3).

## 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!
* Significantly improved memory usage over 3.2
    * Metadata for compiled code uses a lot less memory.
    * Generate more compact code on ARM64
* Compilation speed is now slightly faster than 3.2.
* Add `RubyVM::YJIT.enable` that can enable YJIT at run-time
  * You can start YJIT without modifying command-line arguments or
environment variables.
  * This can also be used to enable YJIT only once your application is
    done booting. `--yjit-disable` can be used if you want to use other
    YJIT options while disabling YJIT at boot.
* Code GC is now disabled by default, and `--yjit-exec-mem-size` is treated
  as a hard limit where copilation of new code stops.
  * Better copy-on-write behavior on servers using unicorn and forking
  * No sudden drops in performance due to code GC.
  * You can still enable code GC if desired with `--yjit-code-gc`
* `ratio_in_yjit` stat produced by `--yjit-stats` is now available in
release builds,
  a special stats or dev build is no longer required to access most stats.
* Exit tracing option now supports sampling
  * `--trace-exits-sample-rate=N`
* `--yjit-perf` is added to facilitate profiling with Linux perf.
* More thorough testing and multiple bug fixes


### M:N thread scheduler

* M:N thread scheduler was introduced. [[Feature
#19842]](https://bugs.ruby-lang.org/issues/19842)
  * M Ruby threads are managed by N native threads (OS threads) so the
thread creation and management cost are reduced.
  * It can break C-extension compatibility so that M:N thread
scheduler is disabled on the main Ractor by default.
      * `RUBY_MN_THREADS=1` environment variable enables M:N threads
on the main Ractor.
      * M:N threads are enabled on non-main Ractors.
  * `RUBY_MAX_CPU=n` environment variable sets maximum number of `N`
(maximum number of native threads). The default value is 8.
      * Since only one Ruby thread per Ractor can run at the same
time, the number of native threads will be used, which is the smaller
of the number specified in `RUBY_MAX_CPU` and the number of running
Ractors. So that single Ractor applications (most of applications)
will use 1 native thread.
      * To support blocking operations, more than `N` native threads
can be used.

## Other Notable New Features



### Language


## Performance improvements

* `defined?(@ivar)` is optimized with Object Shapes.
* Name resolution such as `Socket.getaddrinfo` can now be interrupted
(in environments where pthreads are available). [Feature
#19965](https://bugs.ruby-lang.org/issues/19965)
  * For this purpose, a pthread is now created whenever calling
getaddrinfo or getnameinfo. This incurs some overhead in name
resolution (about 2.5x in our experiments). We do not expect the name
resolution overhead to be a problem for most applications, but if you
observe such, or if you see unexpected affects that you believe are
due to this change, please report them.
* Several performance improvements to the Garbage Collector
  * Young objects referenced by old objects are no longer immediately
      promoted to the old generation. This significantly reduces the
frequency of
      major GC collections. [[Feature
#19678]](https://bugs.ruby-lang.org/issues/19678)
  * A new `REMEMBERED_WB_UNPROTECTED_OBJECTS_LIMIT_RATIO` tuning variable was
      introduced to control the number of unprotected objects cause a major GC
      collection to trigger. The default is set to `0.01` (1%). This
significantly
      reduces the frequency of major GC collection. [[Feature
#19571]](https://bugs.ruby-lang.org/issues/19571)
  * Write Barriers were implemented for many core types that were missing them,
      notably `Time`, `Enumerator`, `MatchData`, `Method`,
`File::Stat`, `BigDecimal`
      and several others. This significantly reduces minor GC
collection time and major
      GC collection frequency.
  * Most core classes are now using Variable Width Allocation, notably
`Hash`, `Time`,
      `Thread::Backtrace`, `Thread::Backtrace::Location`,
`File::Stat`, `Method`.
      This makes these classes faster to allocate and free, use less
memory and reduce
      heap fragmentation.
  * Support for weak references has been added to the garbage
collector. [[Feature #19783]](https://bugs.ruby-lang.org/issues/19783)


## Other notable changes since 3.2

### IRB

IRB has received several enhancements, including but not limited to:

- Advanced `irb:rdbg` integration that provides an equivalent
debugging experience to `pry-byebug`
([doc](https://github.com/ruby/irb#debugging-with-irb)).
- Pager support for `ls`, `show_source` and `show_cmds` commands.
- More accurate and helpful information provided by the `ls` and
`show_source` commands.
- Experimental autocompletion using type analysis
([doc](https://github.com/ruby/irb#type-based-completion)).
- It is now possible to change the font color and font style in the
completion dialog by a newly introduced class Reline::Face
([doc](https://github.com/ruby/ruby/blob/master/doc/reline/face.md))

In addition, IRB has also undergone extensive refactoring and received
dozens of bug fixes to facilitate easier future enhancements.

## Compatibility issues

Note: Excluding feature bug fixes.

* `it` calls without arguments in a block with no ordinary parameters are
  deprecated. `it` will be a reference to the first block parameter in Ruby 3.4.
  [Feature #18980](https://bugs.ruby-lang.org/issues/18980)

### Removed constants

The following deprecated constants are removed.



### Removed methods

The following deprecated methods are removed.

### Removed environment variables

The following deprecated methods are removed.

* Environment variable `RUBY_GC_HEAP_INIT_SLOTS` has been deprecated
and is a no-op. Please use environment variables
`RUBY_GC_HEAP_{0,1,2,3,4}_INIT_SLOTS` instead. [Feature
#19785](https://bugs.ruby-lang.org/issues/19785)

## 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

### Updated C APIs

The following APIs are updated.



### Removed C APIs

The following deprecated APIs are removed.



## Standard library updates

RubyGems and Bundler warn if users require gem that is scheduled to
become the bundled gems in the future version of Ruby.

Targeted libraries are:
  * abbrev
  * base64
  * bigdecimal
  * csv
  * drb
  * getoptlong
  * mutex_m
  * nkf
  * observer
  * racc
  * resolv-replace
  * rinda
  * syslog

The following default gem is added.

* prism 0.15.1

The following default gems are updated.

* RubyGems 3.5.0.dev
* base64 0.2.0
* benchmark 0.3.0
* bigdecimal 3.1.5
* bundler 2.5.0.dev
* cgi 0.4.0
* csv 3.2.8
* date 3.3.4
* delegate 0.3.1
* drb 2.2.0
* english 0.8.0
* erb 4.0.3
* etc 1.4.3.dev.1
* fcntl 1.1.0
* fiddle 1.1.2
* fileutils 1.7.2
* find 0.2.0
* getoptlong 0.2.1
* io-console 0.6.1.dev
* irb 1.8.3
* logger 1.6.0
* mutex_m 0.2.0
* net-http 0.4.0
* net-protocol 0.2.2
* nkf 0.1.3
* observer 0.1.2
* open-uri 0.4.0
* open3 0.2.0
* openssl 3.2.0
* optparse 0.4.0
* ostruct 0.6.0
* pathname 0.3.0
* pp 0.5.0
* prettyprint 0.2.0
* pstore 0.1.3
* psych 5.1.1.1
* rdoc 6.6.0
* reline 0.3.9
* rinda 0.2.0
* securerandom 0.3.0
* shellwords 0.2.0
* singleton 0.2.0
* stringio 3.0.9
* strscan 3.0.7
* syntax_suggest 1.1.0
* tempfile 0.2.0
* time 0.3.0
* timeout 0.4.1
* tmpdir 0.2.0
* tsort 0.2.0
* un 0.3.0
* uri 0.13.0
* weakref 0.1.3
* win32ole 1.8.10
* yaml 0.3.0
* zlib 3.1.0

The following bundled gem is promoted from default gems.

* racc 1.7.3

The following bundled gems are updated.

* minitest 5.20.0
* rake 13.1.0
* test-unit 3.6.1
* rexml 3.2.6
* rss 0.3.0
* net-imap 0.4.4
* net-smtp 0.4.0
* rbs 3.2.2
* typeprof 0.21.8
* debug 1.8.0

See GitHub releases like [Logger](https://github.com/ruby/logger/releases) or
changelog for details of the default gems or bundled gems.

See [NEWS](https://github.com/ruby/ruby/blob/v3_3_0_rc1/NEWS.md)
or [commit logs](https://github.com/ruby/ruby/compare/v3_2_0...v3_3_0_rc1)
for more details.

With those changes, [5414 files changed, 306141 insertions(+), 183575
deletions(-)](https://github.com/ruby/ruby/compare/v3_2_0...v3_3_0_rc1#file_bucket)
since Ruby 3.2.0!


## Download

* <https://cache.ruby-lang.org/pub/ruby/3.3/ruby-3.3.0-rc1.tar.gz>

      SIZE: 21783575
      SHA1: c75a860e06f27b7f69b874757417277c21d1d3f4
      SHA256: c4ff82395a90ef76c7f906b7687026e0ab96b094dcf3a532d9ab97784a073222
      SHA512: 265fb2ffe55af47d8349edffcebe749cc170291227cef55529fe4e67363e4e84b88daa34ffb5364a99c8a0e32110266a34c9a11d62f3bd6f6d47fa76eca641f4

* <https://cache.ruby-lang.org/pub/ruby/3.3/ruby-3.3.0-rc1.tar.xz>

      SIZE: 16163884
      SHA1: 26503f9bdc7d0a05aaa9836f54d3aa9e74a9ead9
      SHA256: 051815637f1fa75a1edf2c54b66d5d5b69563daad777da8dc39543b7754b5290
      SHA512: 82f4acfaad1dc47db27ee3eb952481a95b3474a98059e9e9f5ceb035b690d1faabe99f2ec52371c4089ed1615eb10c395f029088418fec4d26399b65b4f259b9

* <https://cache.ruby-lang.org/pub/ruby/3.3/ruby-3.3.0-rc1.zip>

      SIZE: 26735443
      SHA1: 35583453a7734216b08829ef0ec9ea1bc0d4ae7f
      SHA256: 56dd82e1dd714f2889ca975ae7befbe005675de08839c2cc4a484de2ae65201c
      SHA512: 7fbe414c230aedc9f364512bcbc213038f8f6e4268929a559d2527e2f3e32a140b394e37098ab7e59161236eca8b89cc9e52d73a3be8d7bd44faa91681483f5d

## What is Ruby

Ruby was first developed by Matz (Yukihiro Matsumoto) in 1993,
and is now developed as Open Source. It runs on multiple platforms
and is used all over the world especially for web development.
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