ruby/NEWS.md

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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]

    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:

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

    The following evaluation order is now used:

    1. foo1
    2. foo2
    3. baz1
    4. 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]
  • 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]

      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

  • Kernel

    • Kernel#binding raises RuntimeError if called from a non-Ruby frame (such as a method defined in C). [Bug #18487]
  • MatchData

  • Module

  • Proc

  • 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

  • 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.

Removed methods

The following deprecated methods are removed.

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

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]

Static analysis

RBS

TypeProf

Debugger

error_highlight

IRB Autocomplete and Document Display

Miscellaneous changes