[ruby-core:111218] Ruby 3.2.0 RC 1 Released"

6 Dec 2022

      We are pleased to announce the release of Ruby 3.2.0-rc1. Ruby 3.2
adds many features and performance improvements.

## WASI based WebAssembly support

This is an initial port of WASI based WebAssembly support. This
enables a CRuby binary to be available on a Web browser, a Serverless
Edge environment, or other kinds of WebAssembly/WASI embedders.
Currently this port passes basic and bootstrap test suites not using
the Thread API.

![](https://i.imgur.com/opCgKy2.png)

### Background

[WebAssembly (Wasm)](https://webassembly.org/) was originally
introduced to run programs safely and fast in web browsers. But its
objective - running programs efficiently with security on various
environment - is long wanted not only for web but also by general
applications.

[WASI (The WebAssembly System Interface)](https://wasi.dev/) is
designed for such use cases. Though such applications need to
communicate with operating systems, WebAssembly runs on a virtual
machine which didn't have a system interface. WASI standardizes it.

WebAssembly/WASI support in Ruby intends to leverage those projects.
It enables Ruby developers to write applications which run on such
promised platforms.

### Use case

This support encourages developers to utilize CRuby in a WebAssembly
environment. An example use case is [TryRuby
playground](https://try.ruby-lang.org/playground/)'s CRuby support.
Now you can try original CRuby in your web browser.

### Technical points

Today’s WASI and WebAssembly itself is missing some features to
implement Fiber, exception, and GC because it’s still evolving, and
also for security reasons. So CRuby fills the gap by using Asyncify,
which is a binary transformation technique to control execution in
userland.

In addition, we built [a VFS on top of
WASI](https://github.com/kateinoigakukun/wasi-vfs/wiki/Getting-Started-with-CRuby)
so that we can easily pack Ruby apps into a single .wasm file. This
makes distribution of Ruby apps a bit easier.

### Related links

* [Add WASI based WebAssembly support
#5407](https://github.com/ruby/ruby/pull/5407)
* [An Update on WebAssembly/WASI Support in
Ruby](https://itnext.io/final-report-webassembly-wasi-support-in-ruby-4aface7d90c9)

## Regexp improvements against ReDoS

It is known that Regexp matching may take unexpectedly long. If your
code attempts to match a possibly inefficient Regexp against an
untrusted input, an attacker may exploit it for efficient Denial of
Service (so-called Regular expression DoS, or ReDoS).

We have introduced two improvements that significantly mitigate ReDoS.

### Improved Regexp matching algorithm

Since Ruby 3.2, Regexp's matching algorithm has been greatly improved
by using a memoization technique.

```
# This match takes 10 sec. in Ruby 3.1, and 0.003 sec. in Ruby 3.2

/^a*b?a*$/ =~ "a" * 50000 + "x"
```

![](https://cache.ruby-lang.org/pub/media/ruby320_regex_1.png)
![](https://cache.ruby-lang.org/pub/media/ruby320_regex_2.png)

The improved matching algorithm allows most Regexp matching (about 90%
in our experiments) to be completed in linear time.

(For preview users: this optimization may consume memory proportional
to the input length for each match. We expect no practical problems to
arise because this memory allocation is usually delayed, and a normal
Regexp match should consume at most 10 times as much memory as the
input length. If you run out of memory when matching Regexps in a
real-world application, please report it.)

The original proposal is https://bugs.ruby-lang.org/issues/19104

### Regexp timeout

The optimization above cannot be applied to some kind of regular
expressions, such as those including advanced features (e.g.,
back-references or look-around), or with a huge fixed number of
repetitions. As a fallback measure, a timeout feature for Regexp
matches is also introduced.

```ruby
Regexp.timeout = 1.0

/^a*b?a*()\1$/ =~ "a" * 50000 + "x"
#=> Regexp::TimeoutError is raised in one second
```

Note that `Regexp.timeout` is a global configuration. If you want to
use different timeout settings for some special Regexps, you may want
to use the `timeout` keyword for `Regexp.new`.

```ruby
Regexp.timeout = 1.0

# This regexp has no timeout
long_time_re = Regexp.new("^a*b?a*()\1$", timeout: Float::INFINITY)

long_time_re =~ "a" * 50000 + "x" # never interrupted
```

The original proposal is https://bugs.ruby-lang.org/issues/17837

## Other Notable New Features

### SyntaxSuggest

* The feature of `syntax_suggest` (formerly `dead_end`) is integrated
into Ruby. This helps you find the position of errors such as missing
or superfluous `end`s, to get you back on your way faster, such as in
the following example:

  ```
  Unmatched `end', missing keyword (`do', `def`, `if`, etc.) ?

    1  class Dog
...
2    defbark
4    end
    5  end

[[Feature #18159]]

### ErrorHighlight

* Now it points at the relevant argument(s) for TypeError and ArgumentError

test.rb:2:in `+': nil can't be coerced into Integer (TypeError)

sum = ary[0] + ary[1]
               ^^^^^^
```

### Language

* Anonymous rest and keyword rest arguments can now be passed as
  arguments, instead of just used in method parameters.
  [[Feature #18351]]

    ```ruby
    def foo(*)
      bar(*)
    end
    def baz(**)
      quux(**)
    end
    ```

* A proc that accepts a single positional argument and keywords will
  no longer autosplat. [[Bug #18633]]

  ```ruby
  proc{|a, **k| a}.call([1, 2])
  # Ruby 3.1 and before
  # => 1
  # Ruby 3.2 and after
  # => [1, 2]
  ```

* Constant assignment evaluation order for constants set on explicit
  objects has been made consistent with single attribute assignment
  evaluation order. With this code:

    ```ruby
    foo::BAR = baz
    ```

  `foo` is now called before `baz`. Similarly, for multiple assignments
  to constants,  left-to-right evaluation order is used. With this
  code:

    ```ruby
      foo1::BAR1, foo2::BAR2 = baz1, baz2
    ```

  The following evaluation order is now used:

  1. `foo1`
  2. `foo2`
  3. `baz1`
  4. `baz2`

  [[Bug #15928]]

* The find pattern is no longer experimental.
  [[Feature #18585]]

* Methods taking a rest parameter (like `*args`) and wishing to delegate keyword
  arguments through `foo(*args)` must now be marked with `ruby2_keywords`
  (if not already the case). In other words, all methods wishing to delegate
  keyword arguments through `*args` must now be marked with `ruby2_keywords`,
  with no exception. This will make it easier to transition to other ways of
  delegation once a library can require Ruby 3+. Previously, the
`ruby2_keywords`
  flag was kept if the receiving method took `*args`, but this was a bug and an
  inconsistency. A good technique to find potentially missing `ruby2_keywords`
  is to run the test suite, find the last method which must
  receive keyword arguments for each place where the test suite fails,
and use `puts nil, caller, nil` there. Then check that each
  method/block on the call chain which must delegate keywords is
correctly marked
  with `ruby2_keywords`. [[Bug #18625]] [[Bug #16466]]

    ```ruby
    def target(**kw)
    end

    # Accidentally worked without ruby2_keywords in Ruby 2.7-3.1, ruby2_keywords
    # needed in 3.2+. Just like (*args, **kwargs) or (...) would be needed on
    # both #foo and #bar when migrating away from ruby2_keywords.
    ruby2_keywords def bar(*args)
      target(*args)
    end

    ruby2_keywords def foo(*args)
      bar(*args)
    end

    foo(k: 1)
    ```

## Performance improvements

### YJIT

* YJIT now supports both x86-64 and arm64/aarch64 CPUs on Linux,
MacOS, BSD and other UNIX platforms.
    * This release brings support for Mac M1/M2, AWS Graviton and
Raspberry Pi 4 ARM64 processors.
* Building YJIT requires Rust 1.58.0+. [[Feature #18481]]
    * In order to ensure that CRuby is built with YJIT, please install
rustc >= 1.58.0 and
      run `./configure` with `--enable-yjit`.
    * Please reach out to the YJIT team should you run into any issues.
* Physical memory for JIT code is lazily allocated. Unlike Ruby 3.1,
  the RSS of a Ruby process is minimized because virtual memory pages
  allocated by `--yjit-exec-mem-size` will not be mapped to physical
  memory pages until actually utilized by JIT code.
* Introduce Code GC that frees all code pages when the memory consumption
  by JIT code reaches `--yjit-exec-mem-size`.
    * RubyVM::YJIT.runtime_stats returns Code GC metrics in addition to
      existing `inline_code_size` and `outlined_code_size` keys:
      `code_gc_count`, `live_page_count`, `freed_page_count`, and
`freed_code_size`.
* Most of the statistics produced by RubyVM::YJIT.runtime_stats are
now available in release builds.
    * Simply run ruby with `--yjit-stats` to compute stats (incurs
some run-time overhead).
* YJIT is now optimized to take advantage of object shapes. [[Feature #18776]]
* Take advantage of finer-grained constant invalidation to invalidate
less code when defining new constants. [[Feature #18589]]

### MJIT

* The MJIT compiler is re-implemented in Ruby as a standard library `mjit`.
* MJIT compiler is executed under a forked Ruby process instead of
  doing it in a native thread called MJIT worker. [[Feature #18968]]
    * As a result, Microsoft Visual Studio (MSWIN) is no longer supported.
* MinGW is no longer supported. [[Feature #18824]]
* Rename `--mjit-min-calls` to `--mjit-call-threshold`.
* Change default `--mjit-max-cache` back from 10000 to 100.

### PubGrab

* Bundler 2.4 now uses
[PubGrab](https://github.com/jhawthorn/pub_grub) resolver instead of
[Molinillo](https://github.com/CocoaPods/Molinillo).

  * PubGrab is the next generation solving algorithm used by `pub`
package manager for the Dart programming language.
  * You may get different resolution result after this change. Please
report such cases to [RubyGems/Bundler
issues](https://github.com/rubygems/rubygems/issues)

* RubyGems still uses Molinillo resolver in Ruby 3.2. We plan to
replace it with PubGrab in the future.

## Other notable changes since 3.1

* Hash
    * Hash#shift now always returns nil if the hash is
      empty, instead of returning the default value or
      calling the default proc. [[Bug #16908]]

* MatchData
    * MatchData#byteoffset has been added. [[Feature #13110]]

* Module
    * Module.used_refinements has been added. [[Feature #14332]]
    * Module#refinements has been added. [[Feature #12737]]
    * Module#const_added has been added. [[Feature #17881]]

* Proc
    * Proc#dup returns an instance of subclass. [[Bug #17545]]
    * Proc#parameters now accepts lambda keyword. [[Feature #15357]]

* Refinement
    * Refinement#refined_class has been added. [[Feature #12737]]

* RubyVM::AbstractSyntaxTree
    * Add `error_tolerant` option for `parse`, `parse_file` and `of`.
[[Feature #19013]]

* Set
    * Set is now available as a builtin class without the need for
`require "set"`. [[Feature #16989]]
      It is currently autoloaded via the `Set` constant or a call to
`Enumerable#to_set`.

* String
    * String#byteindex and String#byterindex have been added. [[Feature #13110]]
    * Update Unicode to Version 15.0.0 and Emoji Version 15.0.
[[Feature #18639]]
      (also applies to Regexp)
    * String#bytesplice has been added.  [[Feature #18598]]

* Struct
    * A Struct class can also be initialized with keyword arguments
      without `keyword_init: true` on `Struct.new` [[Feature #16806]]

## Compatibility issues

Note: Excluding feature bug fixes.

### Removed constants

The following deprecated constants are removed.

* `Fixnum` and `Bignum` [[Feature #12005]]
* `Random::DEFAULT` [[Feature #17351]]
* `Struct::Group`
* `Struct::Passwd`

### Removed methods

The following deprecated methods are removed.

* `Dir.exists?` [[Feature #17391]]
* `File.exists?` [[Feature #17391]]
* `Kernel#=~` [[Feature #15231]]
* `Kernel#taint`, `Kernel#untaint`, `Kernel#tainted?`
  [[Feature #16131]]
* `Kernel#trust`, `Kernel#untrust`, `Kernel#untrusted?`
  [[Feature #16131]]

## Stdlib compatibility issues

### No longer bundle 3rd party sources

* We no longer bundle 3rd party sources like `libyaml`, `libffi`.

    * libyaml source has been removed from psych. You may need to
install `libyaml-dev` with Ubuntu/Debian platfrom. The package name is
different for each platform.

    * Bundled libffi source is also removed from `fiddle`

* Psych and fiddle supported static builds with specific versions of
libyaml and libffi sources. You can build psych with libyaml-0.2.5
like this:

    ```bash
    $ ./configure --with-libyaml-source-dir=/path/to/libyaml-0.2.5
    ```

    And you can build fiddle with libffi-3.4.4 like this:

    ```bash
    $ ./configure --with-libffi-source-dir=/path/to/libffi-3.4.4
    ```

  [[Feature #18571]]

## C API updates

### Updated C APIs

The following APIs are updated.

* PRNG update
  `rb_random_interface_t` updated and versioned.
  Extension libraries which use this interface and built for older versions.
  Also `init_int32` function needs to be defined.

### Removed C APIs

The following deprecated APIs are removed.

* `rb_cData` variable.
* "taintedness" and "trustedness" functions. [[Feature #16131]]

### Standard library updates

*   The following default gems are updated.
    * RubyGems 3.4.0.dev
    * benchmark 0.2.1
    * bigdecimal 3.1.3
    * bundler 2.4.0.dev
    * cgi 0.3.6
    * date 3.3.0
    * delegate 0.3.0
    * did_you_mean 1.6.2
    * digest 3.1.1
    * drb 2.1.1
    * erb 4.0.2
    * error_highlight 0.5.1
    * etc 1.4.1
    * fcntl 1.0.2
    * fiddle 1.1.1
    * fileutils 1.7.0
    * forwardable 1.3.3
    * getoptlong 0.2.0
    * io-console 0.5.11
    * io-nonblock 0.2.0
    * io-wait 0.3.0.pre
    * ipaddr 1.2.5
    * irb 1.5.1
    * json 2.6.2
    * logger 1.5.2
    * mutex_m 0.1.2
    * net-http 0.3.1
    * net-protocol 0.2.0
    * nkf 0.1.2
    * open-uri 0.3.0
    * openssl 3.1.0.pre
    * optparse 0.3.0
    * ostruct 0.5.5
    * pathname 0.2.1
    * pp 0.4.0
    * pstore 0.1.2
    * psych 5.0.0
    * racc 1.6.1
    * rdoc 6.5.0
    * reline 0.3.1
    * resolv 0.2.2
    * securerandom 0.2.1
    * set 1.0.3
    * stringio 3.0.3
    * syntax_suggest 1.0.1
    * timeout 0.3.1
    * tmpdir 0.1.3
    * tsort 0.1.1
    * un 0.2.1
    * uri 0.12.0
    * win32ole 1.8.9
    * zlib 3.0.0
*   The following bundled gems are updated.
    * minitest 5.16.3
    * power_assert 2.0.2
    * test-unit 3.5.5
    * net-ftp 0.2.0
    * net-imap 0.3.1
    * net-pop 0.1.2
    * net-smtp 0.3.3
    * rbs 2.8.1
    * typeprof 0.21.3
    * debug 1.7.0

See [NEWS](https://github.com/ruby/ruby/blob/v3_2_0_rc1/NEWS.md)
or [commit logs](https://github.com/ruby/ruby/compare/v3_1_0...v3_2_0_rc1)
for more details.

With those changes, [2846 files changed, 203950 insertions(+), 127153
deletions(-)](https://github.com/ruby/ruby/compare/v3_1_0...v3_2_0_rc1#file_bucket)
since Ruby 3.1.0!

## Download

* <https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-rc1.tar.gz>

      SIZE: 20253652
      SHA1: 9b45af61ef1ae3c21ab88d7c9e30b80060116ac3
      SHA256: 3bb9760c1ac1b66416aaa4899809f6ccd010e57038eaaeca19a383fd56275dac
      SHA512: 798157d785ebae94cb128d3c134fa35e0e90c654972e531cb6562823042f3fb68a270226f7b1cf0c42572ef2b1488a1a3e44f88389ad2a6f9ca4b280a2a8e759

* <https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-rc1.tar.xz>

      SIZE: 14934012
      SHA1: 5576e304786d466410f27a345dc1cb66f2c773f6
      SHA256: 0d45b3af14e84337882a2021235a091ae5dcfc0baaf31dccc479b71d96dd07bc
      SHA512: d38fcb1e09eb9984f3b2347e65ae7406129c2578d068a25d33b5b4f021ec3b567a9abe56c2acbec6d07a3c2b4bc7b485dbd330cbfbb3a96350f60a2bb94d016e

* <https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-rc1.zip>

      SIZE: 24473024
      SHA1: 8fdc85363ce61e0b8f04da36e709d49028d04a75
      SHA256: 7ff32473be108534548e401aaa9092c37a27f73323ea4091c33901c714c87ee5
      SHA512: 07adf6a9c89fdcf420e7b131f40f2b1f4aca036aa6f28539ade26ca552f84a75e0698f77a8b774d2ea52b8c756c4982ef319bda5afa786c081a31dd9873c5ef7

## 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 #12005]: https://bugs.ruby-lang.org/issues/12005
[Feature #12655]: https://bugs.ruby-lang.org/issues/12655
[Feature #12737]: https://bugs.ruby-lang.org/issues/12737
[Feature #13110]: https://bugs.ruby-lang.org/issues/13110
[Feature #14332]: https://bugs.ruby-lang.org/issues/14332
[Feature #15231]: https://bugs.ruby-lang.org/issues/15231
[Feature #15357]: https://bugs.ruby-lang.org/issues/15357
[Bug #15928]:     https://bugs.ruby-lang.org/issues/15928
[Feature #16131]: https://bugs.ruby-lang.org/issues/16131
[Bug #16466]:     https://bugs.ruby-lang.org/issues/16466
[Feature #16806]: https://bugs.ruby-lang.org/issues/16806
[Bug #16889]:     https://bugs.ruby-lang.org/issues/16889
[Bug #16908]:     https://bugs.ruby-lang.org/issues/16908
[Feature #16989]: https://bugs.ruby-lang.org/issues/16989
[Feature #17351]: https://bugs.ruby-lang.org/issues/17351
[Feature #17391]: https://bugs.ruby-lang.org/issues/17391
[Bug #17545]:     https://bugs.ruby-lang.org/issues/17545
[Feature #17881]: https://bugs.ruby-lang.org/issues/17881
[Feature #18639]: https://bugs.ruby-lang.org/issues/18639
[Feature #18159]: https://bugs.ruby-lang.org/issues/18159
[Feature #18351]: https://bugs.ruby-lang.org/issues/18351
[Feature #18481]: https://bugs.ruby-lang.org/issues/18481
[Bug #18487]:     https://bugs.ruby-lang.org/issues/18487
[Feature #18571]: https://bugs.ruby-lang.org/issues/18571
[Feature #18585]: https://bugs.ruby-lang.org/issues/18585
[Feature #18589]: https://bugs.ruby-lang.org/issues/18589
[Feature #18598]: https://bugs.ruby-lang.org/issues/18598
[Bug #18625]:     https://bugs.ruby-lang.org/issues/18625
[Bug #18633]:     https://bugs.ruby-lang.org/issues/18633
[Feature #18685]: https://bugs.ruby-lang.org/issues/18685
[Feature #18776]: https://bugs.ruby-lang.org/issues/18776
[Bug #18782]:     https://bugs.ruby-lang.org/issues/18782
[Feature #18788]: https://bugs.ruby-lang.org/issues/18788
[Feature #18809]: https://bugs.ruby-lang.org/issues/18809
[Bug #19100]:     https://bugs.ruby-lang.org/issues/19100
[Bug #19013]:     https://bugs.ruby-lang.org/issues/19013

[ruby-core:111218] Ruby 3.2.0 RC 1 Released"

NARUSE, Yui