Posted by naruse on 11 Nov 2022
We are pleased to announce the release of Ruby 3.2.0-preview3. 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 Web browser, Serverless Edge environment, and other WebAssembly/WASI embedders. Currently this port passes basic and bootstrap test suites not using Thread API.
Background
WebAssembly (Wasm) is originally introduced to run programs safely and fast in web browsers. But its objective - running programs efficinently with security on various environment - is long wanted not only by web but also by general applications.
WASI (The WebAssembly System Interface) 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 runs on such promised platform.
Use case
This support encourages developers can utilize CRuby in WebAssembly environment. An example use case of it is TryRuby playground’s CRuby support. Now you can try original CRuby in your web browser.
Technical points
Today’s WASI and WebAssembly itself has some missing 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 so that we can easily pack Ruby apps into a single .wasm file. This makes distribution of Ruby apps a bit easier.
Related links
Regexp improvements against ReDoS
It is known that Regexp matching may take unexpectedly long. If your code attempts to match an 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 memoization technique.
# This matching takes 10 sec. in Ruby 3.1, and does 0.003 sec. in Ruby 3.2
/^a*b?a*$/ =~ "a" * 50000 + "x"
The improved matching algorithm allows most of Regexp matching (about 90% in our experiments) to be completed in linear time.
(For preview users: this optimization may consume memory proportional to the input length for each matching. We expect no practical problems to arise because this memory allocation is usually delayed, and a normal Regexp matching should consume at most 10 times as much memory as the input length. If you run out of memory when matching Regexps in a real-world application, please report it.)
The original proposal is https://bugs.ruby-lang.org/issues/19104
Regexp timeout
The optimization above cannot be applied to some kind of regular expressions, such as including advanced features (e.g., back-references or look-around), or with huge fixed number of repetitions. As a fallback measure, a timeout feature for Regexp matching is also introduced.
Regexp.timeout = 1.0
/^a*b?a*()\1$/ =~ "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 timeout
keyword for Regexp.new
.
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
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 platform. The package name is different each platforms. -
bundled libffi source is also removed from
fiddle
-
Language
-
Anonymous rest and keyword rest arguments can now be passed as arguments, instead of just used in method parameters. [Feature #18351]
def foo(*) bar(*) end def baz(**) quux(**) end
-
A proc that accepts a single positional argument and keywords will no longer autosplat. [Bug #18633]
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:
foo::BAR = baz
foo
is now called beforebaz
. Similarly, for multiple assignments to constants, left-to-right evaluation order is used. With this code:foo1::BAR1, foo2::BAR2 = baz1, baz2
The following evaluation order is now used:
foo1
foo2
baz1
baz2
-
Find pattern is no longer experimental. [Feature #18585]
-
Methods taking a rest parameter (like
*args
) and wishing to delegate keyword arguments throughfoo(*args)
must now be marked withruby2_keywords
(if not already the case). In other words, all methods wishing to delegate keyword arguments through*args
must now be marked withruby2_keywords
, with no exception. This will make it easier to transition to other ways of delegation once a library can require Ruby 3+. Previously, theruby2_keywords
flag was kept if the receiving method took*args
, but this was a bug and an inconsistency. A good technique to find the potentially-missingruby2_keywords
is to run the test suite, for where it fails find the last method which must receive keyword arguments, useputs nil, caller, nil
there, and check each method/block on the call chain which must delegate keywords is correctly marked asruby2_keywords
. [Bug #18625] [Bug #16466]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
- Support arm64 / aarch64 on UNIX platforms.
- Building YJIT requires Rust 1.58.1+. [Feature #18481]
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 forparse
,parse_file
andof
. [Feature #19013]
- Add
- Set
- Set is now available as a builtin class without the need for
require "set"
. [Feature #16989] It is currently autoloaded via theSet
constant or a call toEnumerable#to_set
.
- Set is now available as a builtin class without the need for
- String
- String#byteindex and String#byterindex have been added. [Feature #13110]
- Update Unicode to Version 14.0.0 and Emoji Version 14.0. [Feature #18037] (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
onStruct.new
[Feature #16806]
- A Struct class can also be initialized with keyword arguments
without
Compatibility issues
Note: Excluding feature bug fixes.
Removed constants
The following deprecated constants are removed.
Fixnum
andBignum
[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
Psych
no longer bundles libyaml sources. Users need to install the libyaml library themselves via the package system. [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. Alsoinit_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 libraries updates
-
SyntaxSuggest
- The feature of
syntax_suggest
formerlydead_end
is integrated in Ruby. [Feature #18159]
- The feature of
-
ErrorHighlight
- Now it points an argument(s) of TypeError and ArgumentError
test.rb:2:in `+': nil can't be coerced into Integer (TypeError)
sum = ary[0] + ary[1]
^^^^^^
- The following default gems are updated.
- RubyGems 3.4.0.dev
- bigdecimal 3.1.2
- bundler 2.4.0.dev
- cgi 0.3.2
- date 3.2.3
- error_highlight 0.4.0
- etc 1.4.0
- io-console 0.5.11
- io-nonblock 0.1.1
- io-wait 0.3.0.pre
- ipaddr 1.2.4
- json 2.6.2
- logger 1.5.1
- net-http 0.2.2
- net-protocol 0.1.3
- ostruct 0.5.5
- psych 5.0.0.dev
- reline 0.3.1
- securerandom 0.2.0
- set 1.0.3
- stringio 3.0.3
- syntax_suggest 0.0.1
- timeout 0.3.0
- The following bundled gems are updated.
- minitest 5.16.3
- net-imap 0.2.3
- rbs 2.6.0
- typeprof 0.21.3
- debug 1.6.2
- The following default gems are now bundled gems.
See NEWS or commit logs for more details.
With those changes, 2719 files changed, 191269 insertions(+), 120315 deletions(-) since Ruby 3.1.0!
Download
-
https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-preview3.tar.gz
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-
https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-preview3.tar.xz
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-
https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.0-preview3.zip
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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.