Import original article

Author: yous

ko/news/_posts/2021-11-09-ruby-3-1-0-preview1-released.md

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+---
+layout: news_post
+title: "Ruby 3.1.0 Preview 1 Released"
+author: "naruse"
+translator:
+date: 2021-11-09 00:00:00 +0000
+lang: en
+---
+
+{% assign release = site.data.releases | where: "version", "3.1.0-preview1" | first %}
+
+We are pleased to announce the release of Ruby {{ release.version }}.
+
+## YJIT: New experimental in-process JIT compiler
+
+
+Ruby 3.1 merges YJIT, a new in-process JIT compiler developed by Shopify.
+
+Since [Ruby 2.6 introduced MJIT in 2018](https://www.ruby-lang.org/en/news/2018/12/25/ruby-2-6-0-released/), its performance greatly improved, and finally [we achieved Ruby3x3 last year](https://www.ruby-lang.org/en/news/2020/12/25/ruby-3-0-0-released/). But even though Optcarrot has shown impressive speedups, the JIT hasn't benefited real world business applications.
+
+Recently Shopify contributed many Ruby improvements to speed up their Rails application. YJIT is an important contribution, and aims to improve the performance of Rails applications.
+
+Though MJIT is a method-based JIT compiler and uses an external C compiler, YJIT uses Basic Block Versioning and includes JIT compiler inside it. With Lazy Basic Block Versioning (LBBV) it first compiles the beginning of a method, and incrementally compiles the rest when the type of arguments and variables are dynamically determined. See [YJIT: a basic block versioning JIT compiler for CRuby](https://dl.acm.org/doi/10.1145/3486606.3486781) for a detailed introduction.
+
+With this technology, YJIT achieves both fast warmup time and performance improvements on most real-world software, up to 22% on railsbench, 39% on liquid-render.
+
+<!-- 試す人向けのお知らせ -->
+
+YJIT is still an experimental feature, and as such, it is disabled by default. If you want to use this, specify the `--yjit` command-line option to enable YJIT. It is also limited to macOS & Linux on x86-64 platforms for now.
+
+* <https://bugs.ruby-lang.org/issues/18229>
+* <https://shopify.engineering/yjit-just-in-time-compiler-cruby>
+* <https://www.youtube.com/watch?v=PBVLf3yfMs8>
+
+## debug gem: A new debugger
+
+A new debugger [debug.gem](https://github.com/ruby/debug) is bundled. debug.gem is fast debugger implementation and it provides many features like remote debugging, colorful REPL, IDE (VSCode) integration and more. It replaces `lib/debug.rb` standard library.
+
+## error_highlight: Fine-grained error location in backtrace
+
+A built-in gem, error_highlight, has been introduced. It includes fine-grained error location in backtrace:
+
+```
+$ ruby test.rb
+test.rb:1:in `<main>': undefined method `time' for 1:Integer (NoMethodError)
+
+1.time {}
+ ^^^^^
+Did you mean?  times
+```
+
+This gem is enabled by default. You can disable it by using a command-line option `--disable-error_highlight`. See [the repository](https://github.com/ruby/error_highlight) in detail.
+
+## Irb improvement
+
+To be described in next preview.
+
+## Other Notable New Features
+
+### Language
+
+* Values in Hash literals and keyword arguments can be omitted. [Feature #14579]
+  * `{x:, y:}` is a syntax sugar of `{x: x, y: y}`.
+  * `foo(x:, y:)` is a syntax sugar of `foo(x: x, y: y)`.
+
+* Pin operator in pattern matching now takes an expression. [Feature #17411]
+
+```ruby
+Prime.each_cons(2).lazy.find_all{_1 in [n, ^(n + 2)]}.take(3).to_a
+#=> [[3, 5], [5, 7], [11, 13]]
+```
+
+
+### RBS
+
+RBS is a language to describe the structure of Ruby programs. See [the repository](https://github.com/ruby/rbs) for detail.
+
+Updates since Ruby 3.0.0:
+
+* `rbs collection` has been introduced to manage gems' RBSs.  [doc](https://github.com/ruby/rbs/blob/master/docs/collection.md)
+* Many signatures for built-in and standard libraries have been added/updated.
+* It includes many bug fixes and performance improvements too.
+
+See [the CHANGELOG.md](https://github.com/ruby/rbs/blob/master/CHANGELOG.md) for more information.
+
+### TypeProf
+
+TypeProf is a static type analyzer for Ruby. It generates a prototype of RBS from non-type-annotated Ruby code. See [the document](https://github.com/ruby/typeprof/blob/master/doc/doc.md) for detail.
+
+Updates since Ruby 3.0.0:
+
+* [Experimental IDE support](https://github.com/ruby/typeprof/blob/master/doc/ide.md) has been implemented.
+* Many bug fixes and performance improvements.
+
+## Performance improvements
+
+* MJIT
+  * For workloads like Rails, the default `--jit-max-cache` is changed from 100 to 10000.
+    The JIT compiler no longer skips compilation of methods longer than 1000 instructions.
+  * To support Zeitwerk of Rails, JIT-ed code is no longer cancelled
+    when a TracePoint for class events is enabled.
+
+## Other notable changes since 3.0
+
+* One-line pattern matching, e.g., `ary => [x, y, z]`, is no longer experimental.
+* Multiple assignment evaluation order has been changed slightly. [[Bug #4443]](https://bugs.ruby-lang.org/issues/4443)
+  * `foo[0], bar[0] = baz, qux` was evaluated in order `baz`, `qux`, `foo`, and then `bar` in Ruby 3.0. In Ruby 3.1, it is evaluated in order `foo`, `bar`, `baz`, and then `qux`.
+* Variable Width Allocation: Strings (experimental) [[Bug #18239]](https://bugs.ruby-lang.org/issues/18239)
+
+### Standard libraries updates
+
+* Some standard libraries are updated.
+  * RubyGems
+  * Bundler
+  * RDoc 6.4.0
+  * ReLine
+  * JSON 2.6.0
+  * Psych 4.0.2
+  * FileUtils 1.6.0
+  * Fiddle
+  * StringIO 3.0.1
+  * IO::Console 0.5.9
+  * IO::Wait 0.2.0
+  * CSV
+  * Etc 1.3.0
+  * Date 3.2.0
+  * Zlib 2.1.1
+  * StringScanner
+  * IpAddr
+  * Logger 1.4.4
+  * OStruct 0.5.0
+  * Irb
+  * Racc 1.6.0
+  * Delegate 0.2.0
+  * Benchmark 0.2.0
+  * CGI 0.3.0
+  * Readline(C-ext) 0.1.3
+  * Timeout 0.2.0
+  * YAML 0.2.0
+  * URI 0.11.0
+  * OpenSSL
+  * DidYouMean
+  * Weakref 0.1.1
+  * Tempfile 0.1.2
+  * TmpDir 0.1.2
+  * English 0.7.1
+  * Net::Protocol 0.1.2
+  * Net::Http 0.2.0
+  * BigDecimal
+  * OptionParser 0.2.0
+  * Set
+  * Find 0.1.1
+  * Rinda 0.1.1
+  * Erb
+  * NKF 0.1.1
+  * Base64 0.1.1
+  * OpenUri 0.2.0
+  * SecureRandom 0.1.1
+  * Resolv 0.2.1
+  * Resolv::Replace 0.1.0
+  * Time 0.2.0
+  * PP 0.2.1
+  * Prettyprint 0.1.1
+  * Drb 2.1.0
+  * Pathname 0.2.0
+  * Digest 3.1.0.pre2
+  * Un 0.2.0
+* The following bundled gems are updated.
+  * minitest 5.14.4
+  * power_assert 2.0.1
+  * rake 13.0.6
+  * test-unit 3.5.0
+  * rbs 1.6.2
+  * typeprof 0.20.0
+* The following default gems are now bundled gems.
+  * net-ftp
+  * net-imap
+  * net-pop
+  * net-smtp
+  * matrix
+  * prime
+
+See [NEWS](https://github.com/ruby/ruby/blob/{{ release.tag }}/NEWS.md)
+or [commit logs](https://github.com/ruby/ruby/compare/v3_0_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_0_0...{{ release.tag }}#file_bucket)
+since Ruby 3.0.0!
+
+## 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.