NEWS for Ruby 3.2.0¶ ↑

This document is a list of user-visible feature changes since the 3.1.0 release, except for bug fixes.

Note that each entry is kept to a minimum, see links for details.

Language changes¶ ↑

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]

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:
```
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:

foo1
foo2
baz1
baz2

[Bug #15928]

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 the potentially-missing ruby2_keywords is to run the test suite, for where it fails find the last method which must receive keyword arguments, use puts nil, caller, nil there, and check each method/block on the call chain which must delegate keywords is correctly marked as ruby2_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)
```
eval and related methods are able to generate code coverage. Enabled using Coverage.setup(:all) or Coverge.setup(eval: true). [Feature #19008]
Coverage.supported?(mode) enables detection of what coverage modes are supported. [Feature #19026]

Command line options¶ ↑

Core classes updates¶ ↑

Note: We’re only listing outstanding class updates.

Fiber::Scheduler
- Introduce Fiber::Scheduler#io_select for non-blocking IO.select. [Feature #19060]
- Introduce Fiber::Scheduler#io_select for non-blocking IO.select. [Feature #19060]
IO
- Introduce IO#timeout= and IO#timeout which can cause IO::TimeoutError to be raised if a blocking operation exceeds the specified timeout. [Feature #18630]
```
STDIN.timeout = 1
STDIN.read # => Blocking operation timed out! (IO::TimeoutError)
```
Class
- Class#attached_object, which returns the object for which the receiver is the singleton class. Raises TypeError if the receiver is not a singleton class. [Feature #12084]
"'ruby class Foo; end

Foo.singleton_class.attached_object #=> Foo Foo.new.singleton_class.attached_object #=> #<Foo:0x000000010491a370> Foo.attached_object #=> TypeError: Foo' is not a singleton class nil.singleton_class.attached_object #=> TypeError:NilClass’ is not a singleton class “‘
Data
- New core class to represent simple immutable value object. The class is similar to Struct and partially shares an implementation, but has more lean and strict API. [Feature #16122]
Encoding
- Encoding#replicate has been deprecated and will be removed in 3.3. [Feature #18949]
- The dummy Encoding::UTF_16 and Encoding::UTF_32 encodings no longer try to dynamically guess the endian based on a byte order mark. Use Encoding::UTF_16BE/UTF_16LE and Encoding::UTF_32BE/UTF_32LE instead. This change speeds up getting the encoding of a String. [Feature #18949]
Enumerator
- Enumerator.product has been added. Enumerator::Product is the implementation. [Feature #18685]
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]
Integer
- Integer#ceildiv has been added. [Feature #18809]
Kernel
- Kernel#binding raises RuntimeError if called from a non-Ruby frame (such as a method defined in C). [Bug #18487]
MatchData
- MatchData#byteoffset has been added. [Feature #13110]
- MatchData#deconstruct has been added. [Feature #18821]
- MatchData#deconstruct_keys has been added. [Feature #18821]
Module
- Module.used_refinements has been added. [Feature #14332]
- Module#refinements has been added. [Feature #12737]
- Module#const_added has been added. [Feature #17881]
- Module#undefined_instance_methods has been added. [Feature #12655]
Proc
- Proc#dup returns an instance of subclass. [Bug #17545]
- Proc#parameters now accepts lambda keyword. [Feature #15357]
Process
- Added RLIMIT_NPTS constant to FreeBSD platform
Regexp
- Regexp.new now supports passing the regexp flags not only as an Integer, but also as a String. Unknown flags raise ArgumentError. Otherwise, anything other than true, false, nil or Integer will be warned. [Feature #18788]
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 built-in class without the need for require "set". [Feature #16989] It is currently autoloaded via the Set constant or a call to Enumerable#to_set.
Socket
- Added the following constants for supported platforms.
- SO_INCOMING_CPU
- SO_INCOMING_NAPI_ID
- SO_RTABLE
- SO_SETFIB
- SO_USER_COOKIE
- TCP_KEEPALIVE
- TCP_CONNECTION_INFO
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 on Struct.new [Feature #16806]
TracePoint
- TracePoint#binding now returns nil for c_call/c_return TracePoints. [Bug #18487]
- TracePoint#enable target_thread keyword argument now defaults to the current thread if target and target_line keyword arguments are not passed. [Bug #16889]

Stdlib updates¶ ↑

SyntaxSuggest
The feature of syntax_suggest formerly dead_end is integrated in Ruby. [Feature #18159]
The following default gems are updated.
- RubyGems 3.4.0.dev
- bigdecimal 3.1.2
- bundler 2.4.0.dev
- cgi 0.3.3
- date 3.2.3
- erb 3.0.0
- error_highlight 0.5.0
- etc 1.4.0
- fiddle 1.1.1
- io-console 0.5.11
- io-nonblock 0.1.1
- io-wait 0.3.0.pre
- ipaddr 1.2.4
- irb 1.4.2
- json 2.6.2
- logger 1.5.1
- net-http 0.3.0
- net-protocol 0.1.3
- openssl 3.1.0.pre
- 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
- 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 2.7.0
- typeprof 0.21.3
- debug 1.6.3
The following default gems are now bundled gems.

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]

Source code incompatiblity of extension libraries [Bug #19100]¶ ↑

Extension libraries provide PRNG, subclasses of Random, need updates. See [PRNG update] below for more information.

Stdlib compatibility issues¶ ↑

Psych no longer bundles libyaml sources. And also Fiddle no longer bundles libffi sources. Users need to install the libyaml/libffi 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. 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]

Implementation improvements¶ ↑

Fixed several race conditions in Kernel#autoload. [Bug #18782]
Cache invalidation for expressions referencing constants is now more fine-grained. RubyVM.stat(:global_constant_state) was removed because it was closely tied to the previous caching scheme where setting any constant invalidates all caches in the system. New keys, :constant_cache_invalidations and :constant_cache_misses, were introduced to help with use cases for :global_constant_state. [Feature #18589]

JIT¶ ↑

YJIT¶ ↑

Support arm64 / aarch64 on UNIX platforms.
Building YJIT requires Rust 1.58.1+. [Feature #18481]
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.

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]