11 KiB
NEWS for Ruby 3.0.0
This document is a list of user visible feature changes since the 2.7.0 release, except for bug fixes.
Note that each entry is kept so brief that no reason behind or reference
information is supplied with. For a full list of changes with all
sufficient information, see the ChangeLog file or Redmine
(e.g. https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER
).
Language changes
-
Keyword arguments are now separated from positional arguments. Code that resulted in deprecation warnings in Ruby 2.7 will now result in ArgumentError or different behavior. [Feature #14183]
-
Arguments forwarding (
...
) now supports leading arguments. [Feature #16378]def method_missing(meth, ...) send(:"do_#{meth}", ...) end
-
Procs accepting a single rest argument and keywords are no longer subject to autosplatting. This now matches the behavior of Procs accepting a single rest argument and no keywords. [Feature #16166]
pr = proc{|*a, **kw| [a, kw]} pr.call([1]) # 2.7 => [[1], {}] # 3.0 => [[[1]], {}] pr.call([1, {a: 1}]) # 2.7 => [[1], {:a=>1}] # and deprecation warning # 3.0 => [[[1, {:a=>1}]], {}]
-
$SAFE is now a normal global variable with no special behavior. C-API methods related to $SAFE have been removed. [Feature #16131]
-
yield in singleton class definitions in methods is now a SyntaxError instead of a warning. yield in a class definition outside of a method is now a SyntaxError instead of a LocalJumpError. [Feature #15575]
-
Find pattern is added. [Feature #16828]
case ["a", 1, "b", "c", 2, "d", "e", "f", 3] in [*pre, String => x, String => y, *post] p pre #=> ["a", 1] p x #=> "b" p y #=> "c" p post #=> [2, "d", "e", "f", 3] end
-
When a class variable is overtaken by the same definition in an ancestor class/module, a RuntimeError is now raised (previously, it only issued a warning in verbose mode. Additionally, accessing a class variable from the toplevel scope is now a RuntimeError. [Bug #14541]
-
Rightward assignment statement is added. [EXPERIMENTAL] [Feature #15921]
fib(10) => x
-
Endless method definition is added. [EXPERIMENTAL] [Feature #16746]
def square(x) = x * x
Command line options
--help
option
When the environment variable RUBY_PAGER
or PAGER
is present and has
non-empty value, and the standard input and output are tty, --help
option shows the help message via the pager designated by the value.
[Feature #16754]
Core classes updates
Outstanding ones only.
-
Dir
-
Modified method
- Dir.glob and Dir.[] now sort the results by default, and
accept
sort:
keyword option. [Feature #8709]
- Dir.glob and Dir.[] now sort the results by default, and
accept
-
-
ENV
-
New method
- ENV.except, which returns a hash excluding the given keys and their values. [Feature #15822]
-
-
Hash
-
Modified method
- Hash#transform_keys now accepts a hash that maps keys to new keys. [Feature #16274]
-
New method
- Hash#except, which returns a hash excluding the given keys and their values. [Feature #15822]
-
-
Kernel
-
Modified method
-
Kernel#clone when called with
freeze: false
keyword will call#initialize_clone
with thefreeze: false
keyword. [Bug #14266] -
Kernel#clone when called with
freeze: true
keyword will call#initialize_clone
with thefreeze: true
keyword, and will return a frozen copy even if the receiver is unfrozen. [Feature #16175] -
Kernel#eval when called with two arguments will use "(eval)" for
__FILE__
and 1 for__LINE__
in the evaluated code. [Bug #4352] -
Kernel#lambda now warns if called without a literal block. [Feature #15973]
-
-
-
Module
-
Modified method
-
Module#include and #prepend now affect classes and modules that have already included or prepended the receiver, mirroring the behavior if the arguments were included in the receiver before the other modules and classes included or prepended the receiver. [Feature #9573]
class C; end module M1; end module M2; end C.include M1 M1.include M2 p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
-
-
-
Symbol
-
Modified method
- Symbol#to_proc now returns a lambda Proc. [Feature #16260]
-
New method
- Symbol#name, which returns the name of the symbol if it is named. The returned string cannot be modified. [Feature #16150]
-
-
Warning
-
Modified method
- Warning#warn now supports a category kwarg. [Feature #17122]
-
Stdlib updates
Outstanding ones only.
-
RubyGems
- Update to RubyGems 3.2.0.pre1
-
Bundler
- Update to Bundler 2.2.0.dev
-
Net::HTTP
-
New method
- Add Net::HTTP#verify_hostname= and Net::HTTP#verify_hostname to skip hostname verification. [Feature #16555]
-
Modified method
- Net::HTTP.get, Net::HTTP.get_response, and Net::HTTP.get_print can take request headers as a Hash in the second argument when the first argument is a URI. [Feature #16686]
-
Compatibility issues
Excluding feature bug fixes.
-
Regexp literals are frozen [Feature #8948] [Feature #16377]
/foo/.frozen? #=> true
-
EXPERIMENTAL: Hash#each consistently yields a 2-element array [Bug #12706]
- Now
{ a: 1 }.each(&->(k, v) { })
raises an ArgumentError due to lambda's arity check. - This is experimental; if it brings a big incompatibility issue, it may be reverted until 2.8/3.0 release.
- Now
-
When writing to STDOUT redirected to a closed pipe, no broken pipe error message will be shown now. [Feature #14413]
-
TRUE
/FALSE
/NIL
constants are no longer defined. -
Integer#zero?
overridesNumeric#zero?
for optimization. [Misc #16961]
Stdlib compatibility issues
-
Default gems
-
The following libraries are promoted the default gems from stdlib.
- abbrev
- base64
- English
- erb
- find
- io-nonblock
- io-wait
- net-ftp
- net-http
- net-imap
- net-protocol
- nkf
- open-uri
- optparse
- resolv
- resolv-replace
- rinda
- securerandom
- set
- shellwords
- tempfile
- time
- tmpdir
- tsort
- weakref
-
-
Bundled gems
- net-telnet and xmlrpc have been removed from the bundled gems. If you are interested in maintaining them, please comment on your plan to https://github.com/ruby/xmlrpc or https://github.com/ruby/net-telnet.
-
SDBM have been removed from ruby standard library. [Bug #8446]
- The issues of sdbm will be handled at https://github.com/ruby/sdbm
C API updates
-
C API functions related to $SAFE have been removed. [Feature #16131]
-
C API header file
ruby/ruby.h
was split. [GH-2991] Should have no impact on extension libraries, but users might experience slow compilations.
Implementation improvements
-
New method cache mechanism for Ractor [Feature #16614]
- TODO: ko1 will write details
-
The number of hashes allocated when using a keyword splat in a method call has been reduced to a maximum of 1, and passing a keyword splat to a method that accepts specific keywords does not allocate a hash.
-
super
is optimized when the same type of method is called in the previous call if it's not refinements or an attr reader or writer.
JIT
-
Native functions shared by multiple methods are deduplicated on JIT compaction.
-
Decrease code size of hot paths by some optimizations and partitioning cold paths.
-
Not only pure Ruby methods but also some C methods skip pushing a method frame.
Kernel#class
,Integer#zero?
-
Always generate appropriate code for
==
,nil?
, and!
calls depending on a receiver class. -
Optimize instance variable access in some core classes like Hash and their subclasses
-
Eliminate VM register access on a method return
-
Optimize C method call a little
Miscellaneous changes
-
Methods using
ruby2_keywords
will no longer keep empty keyword splats, those are now removed just as they are for methods not usingruby2_keywords
. -
Taint deprecation warnings are now issued in regular mode in addition to verbose warning mode. [Feature #16131]
-
When an exception is caught in the default handler, the error message and backtrace are printed in order from the innermost. [Feature #8661]