cp 2024-12-12-ruby-3-4-0-rc1-released.md

Author: riseshia

ko/news/_posts/2024-12-12-ruby-3-4-0-rc1-released.md

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+---
+layout: news_post
+title: "Ruby 3.4.0 rc1 Released"
+author: "naruse"
+translator:
+date: 2024-12-12 00:00:00 +0000
+lang: en
+---
+
+{% assign release = site.data.releases | where: "version", "3.4.0-rc1" | first %}
+We are pleased to announce the release of Ruby {{ release.version }}.
+
+## Prism
+
+Switch the default parser from parse.y to Prism. [[Feature #20564]]
+
+## Modular GC
+
+* Alternative garbage collector (GC) implementations can be loaded dynamically
+  through the modular garbage collector feature. To enable this feature,
+  configure Ruby with `--with-modular-gc` at build time. GC libraries can be
+  loaded at runtime using the environment variable `RUBY_GC_LIBRARY`.
+  [[Feature #20351]]
+
+* Ruby's built-in garbage collector has been split into a separate file at
+  `gc/default/default.c` and interacts with Ruby using an API defined in
+  `gc/gc_impl.h`. The built-in garbage collector can now also be built as a
+  library using `make modular-gc MODULAR_GC=default` and enabled using the
+  environment variable `RUBY_GC_LIBRARY=default`. [[Feature #20470]]
+
+* An experimental GC library is provided based on [MMTk](https://www.mmtk.io/).
+  This GC library can be built using `make modular-gc MODULAR_GC=mmtk` and
+  enabled using the environment variable `RUBY_GC_LIBRARY=mmtk`. This requires
+  the Rust toolchain on the build machine. [[Feature #20860]]
+
+
+## Language changes
+
+* String literals in files without a `frozen_string_literal` comment now emit a deprecation warning
+  when they are mutated.
+  These warnings can be enabled with `-W:deprecated` or by setting `Warning[:deprecated] = true`.
+  To disable this change, you can run Ruby with the `--disable-frozen-string-literal`
+  command line argument. [[Feature #20205]]
+
+* `it` is added to reference a block parameter. [[Feature #18980]]
+
+* Keyword splatting `nil` when calling methods is now supported.
+  `**nil` is treated similarly to `**{}`, passing no keywords,
+  and not calling any conversion methods.  [[Bug #20064]]
+
+* Block passing is no longer allowed in index.  [[Bug #19918]]
+
+* Keyword arguments are no longer allowed in index.  [[Bug #20218]]
+
+## YJIT
+
+TL;DR:
+* Better performance on most benchmarks on both x86-64 and arm64 platforms.
+* Reduced memory usage of compilation metadata
+* Multiple bug fixes. YJIT is now even more robust and better tested.
+
+New features:
+* Add unified memory limit via `--yjit-mem-size` command-line option (default 128MiB)
+  which tracks total YJIT memory usage and is more intuitive than the
+  old `--yjit-exec-mem-size`.
+* More statistics now always available via `RubyVM::YJIT.runtime_stats`
+* Add compilation log to track what gets compiled via `--yjit-log`
+  * Tail of the log also available at run-time via `RubyVM::YJIT.log`
+* Add support for shareable consts in multi-ractor mode
+* Can now trace counted exits with `--yjit-trace-exits=COUNTER`
+
+New optimizations:
+* Compressed context reduces memory needed to store YJIT metadata
+* Improved allocator with ability to allocate registers for local variables
+* When YJIT is enabled, use more Core primitives written in Ruby:
+  * `Array#each`, `Array#select`, `Array#map` rewritten in Ruby for better performance [[Feature #20182]].
+* Ability to inline small/trivial methods such as:
+  * Empty methods
+  * Methods returning a constant
+  * Methods returning `self`
+  * Methods directly returning an argument
+* Specialized codegen for many more runtime methods
+* Optimize `String#getbyte`, `String#setbyte` and other string methods
+* Optimize bitwise operations to speed up low-level bit/byte manipulation
+* Various other incremental optimizations
+
+## Core classes updates
+
+Note: We're only listing outstanding class updates.
+
+* Exception
+
+  * `Exception#set_backtrace` now accepts an array of `Thread::Backtrace::Location`.
+    `Kernel#raise`, `Thread#raise` and `Fiber#raise` also accept this new format. [[Feature #13557]]
+
+* Range
+
+  * `Range#size` now raises `TypeError` if the range is not iterable. [[Misc #18984]]
+
+
+
+## Compatibility issues
+
+Note: Excluding feature bug fixes.
+
+* Error messages and backtrace displays have been changed.
+  * Use a single quote instead of a backtick as a opening quote. [[Feature #16495]]
+  * Display a class name before a method name (only when the class has a permanent name). [[Feature #19117]]
+  * `Kernel#caller`, `Thread::Backtrace::Location`'s methods, etc. are also changed accordingly.
+
+  ```
+  Old:
+  test.rb:1:in `foo': undefined method `time' for an instance of Integer
+          from test.rb:2:in `<main>'
+
+  New:
+  test.rb:1:in 'Object#foo': undefined method 'time' for an instance of Integer
+          from test.rb:2:in '<main>'
+  ```
+
+## C API updates
+
+* `rb_newobj` and `rb_newobj_of` (and corresponding macros `RB_NEWOBJ`, `RB_NEWOBJ_OF`, `NEWOBJ`, `NEWOBJ_OF`) have been removed. [[Feature #20265]]
+* Removed deprecated function `rb_gc_force_recycle`. [[Feature #18290]]
+
+## Miscellaneous changes
+
+* Passing a block to a method which doesn't use the passed block will show
+  a warning on verbose mode (`-w`).
+  [[Feature #15554]]
+
+* Redefining some core methods that are specially optimized by the interpeter
+  and JIT like `String.freeze` or `Integer#+` now emits a performance class
+  warning (`-W:performance` or `Warning[:performance] = true`).
+  [[Feature #20429]]
+
+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/{{ release.tag }}/NEWS.md)
+or [commit logs](https://github.com/ruby/ruby/compare/v3_3_0...{{ release.tag }})
+for more details.
+
+With those changes, [{{ release.stats.files_changed }} files changed, {{ release.stats.insertions }} insertions(+), {{ release.stats.deletions }} deletions(-)](https://github.com/ruby/ruby/compare/v3_3_0...{{ release.tag }}#file_bucket)
+since Ruby 3.3.0!
+
+
+## Download
+
+* <{{ release.url.gz }}>
+
+      SIZE: {{ release.size.gz }}
+      SHA1: {{ release.sha1.gz }}
+      SHA256: {{ release.sha256.gz }}
+      SHA512: {{ release.sha512.gz }}
+
+* <{{ release.url.xz }}>
+
+      SIZE: {{ release.size.xz }}
+      SHA1: {{ release.sha1.xz }}
+      SHA256: {{ release.sha256.xz }}
+      SHA512: {{ release.sha512.xz }}
+
+* <{{ release.url.zip }}>
+
+      SIZE: {{ release.size.zip }}
+      SHA1: {{ release.sha1.zip }}
+      SHA256: {{ release.sha256.zip }}
+      SHA512: {{ release.sha512.zip }}
+
+## 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.
+
+[Feature #13557]: https://bugs.ruby-lang.org/issues/13557
+[Feature #15554]: https://bugs.ruby-lang.org/issues/15554
+[Feature #16495]: https://bugs.ruby-lang.org/issues/16495
+[Feature #18290]: https://bugs.ruby-lang.org/issues/18290
+[Feature #18980]: https://bugs.ruby-lang.org/issues/18980
+[Misc #18984]:    https://bugs.ruby-lang.org/issues/18984
+[Feature #19117]: https://bugs.ruby-lang.org/issues/19117
+[Bug #19918]:     https://bugs.ruby-lang.org/issues/19918
+[Bug #20064]:     https://bugs.ruby-lang.org/issues/20064
+[Feature #20182]: https://bugs.ruby-lang.org/issues/20182
+[Feature #20205]: https://bugs.ruby-lang.org/issues/20205
+[Bug #20218]:     https://bugs.ruby-lang.org/issues/20218
+[Feature #20265]: https://bugs.ruby-lang.org/issues/20265
+[Feature #20351]: https://bugs.ruby-lang.org/issues/20351
+[Feature #20429]: https://bugs.ruby-lang.org/issues/20429
+[Feature #20470]: https://bugs.ruby-lang.org/issues/20470
+[Feature #20564]: https://bugs.ruby-lang.org/issues/20564
+[Feature #20860]: https://bugs.ruby-lang.org/issues/20860