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diff --git a/doc/NEWS-3.1.0.md b/doc/NEWS-3.1.0.md new file mode 100644 index 0000000000..d5a14175e3 --- /dev/null +++ b/doc/NEWS-3.1.0.md @@ -0,0 +1,657 @@ +# NEWS for Ruby 3.1.0 + +This document is a list of user-visible feature changes +since the **3.0.0** release, except for bug fixes. + +Note that each entry is kept to a minimum, see links for details. + +## Language changes + +* The block argument can now be anonymous if the block will + only be passed to another method. [[Feature #11256]] + + ```ruby + def foo(&) + bar(&) + end + ``` + +* Pin operator now takes an expression. [[Feature #17411]] + + ```ruby + Prime.each_cons(2).lazy.find_all{_1 in [n, ^(n + 2)]}.take(3).to_a + #=> [[3, 5], [5, 7], [11, 13]] + ``` + +* Pin operator now supports instance, class, and global variables. + [[Feature #17724]] + + ```ruby + @n = 5 + Prime.each_cons(2).lazy.find{_1 in [n, ^@n]} + #=> [3, 5] + ``` + +* One-line pattern matching is no longer experimental. + +* Parentheses can be omitted in one-line pattern matching. + [[Feature #16182]] + + ```ruby + [0, 1] => _, x + {y: 2} => y: + x #=> 1 + y #=> 2 + ``` + +* Multiple assignment evaluation order has been made consistent with + single assignment evaluation order. With single assignment, Ruby + uses a left-to-right evaluation order. With this code: + + ```ruby + foo[0] = bar + ``` + + The following evaluation order is used: + + 1. `foo` + 2. `bar` + 3. `[]=` called on the result of `foo` + + In Ruby before 3.1.0, multiple assignment did not follow this + evaluation order. With this code: + + ```ruby + foo[0], bar.baz = a, b + ``` + + Versions of Ruby before 3.1.0 would evaluate in the following + order + + 1. `a` + 2. `b` + 3. `foo` + 4. `[]=` called on the result of `foo` + 5. `bar` + 6. `baz=` called on the result of `bar` + + Starting in Ruby 3.1.0, the evaluation order is now consistent with + single assignment, with the left-hand side being evaluated before + the right-hand side: + + 1. `foo` + 2. `bar` + 3. `a` + 4. `b` + 5. `[]=` called on the result of `foo` + 6. `baz=` called on the result of `bar` + + [[Bug #4443]] + +* Values in Hash literals and keyword arguments can be omitted. + [[Feature #14579]] + + For example, + + * `{x:, y:}` is a syntax sugar of `{x: x, y: y}`. + * `foo(x:, y:)` is a syntax sugar of `foo(x: x, y: y)`. + + Constant names, local variable names, and method names are allowed as + key names. Note that a reserved word is considered as a local + variable or method name even if it's a pseudo variable name such as + `self`. + +* Non main-Ractors can get instance variables (ivars) of classes/modules + if ivars refer to shareable objects. + [[Feature #17592]] + +* A command syntax is allowed in endless method definitions, i.e., + you can now write `def foo = puts "Hello"`. + Note that `private def foo = puts "Hello"` does not parse. + [[Feature #17398]] + +## Command line options + +* `--disable-gems` is now explicitly declared as "just for debugging". + Never use it in any real-world codebase. + [[Feature #17684]] + +## Core classes updates + +Note: We're only listing outstanding class updates. + +* Array + + * Array#intersect? is added. [[Feature #15198]] + +* Class + + * Class#subclasses, which returns an array of classes + directly inheriting from the receiver, not + including singleton classes. + [[Feature #18273]] + + ```ruby + class A; end + class B < A; end + class C < B; end + class D < A; end + A.subclasses #=> [D, B] + B.subclasses #=> [C] + C.subclasses #=> [] + ``` + +* Enumerable + + * Enumerable#compact is added. [[Feature #17312]] + + * Enumerable#tally now accepts an optional hash to count. [[Feature #17744]] + + * Enumerable#each_cons and each_slice to return a receiver. [[GH-1509]] + + ```ruby + [1, 2, 3].each_cons(2){} + # 3.0 => nil + # 3.1 => [1, 2, 3] + + [1, 2, 3].each_slice(2){} + # 3.0 => nil + # 3.1 => [1, 2, 3] + ``` + +* Enumerator::Lazy + + * Enumerator::Lazy#compact is added. [[Feature #17312]] + +* File + + * File.dirname now accepts an optional argument for the level to + strip path components. [[Feature #12194]] + +* GC + + * "GC.measure_total_time = true" enables the measurement of GC. + Measurement can introduce overhead. It is enabled by default. + GC.measure_total_time returns the current setting. + GC.stat[:time] or GC.stat(:time) returns measured time + in milli-seconds. [[[Feature #10917]]] + + * GC.total_time returns measured time in nano-seconds. [[[Feature #10917]]] + +* Integer + + * Integer.try_convert is added. [[Feature #15211]] + +* Kernel + + + * Kernel#load now accepts a module as the second argument, + and will load the file using the given module as the + top-level module. [[Feature #6210]] + +* Marshal + + * Marshal.load now accepts a `freeze: true` option. + All returned objects are frozen except for `Class` and + `Module` instances. Strings are deduplicated. [[Feature #18148]] + +* MatchData + + * MatchData#match is added [[Feature #18172]] + + * MatchData#match_length is added [[Feature #18172]] + +* Method / UnboundMethod + + * Method#public?, Method#private?, Method#protected?, + UnboundMethod#public?, UnboundMethod#private?, + UnboundMethod#protected? have been added. [[Feature #11689]] + +* Module + + * Module#prepend now modifies the ancestor chain if the receiver + already includes the argument. Module#prepend still does not + modify the ancestor chain if the receiver has already prepended + the argument. [[Bug #17423]] + + * Module#private, #public, #protected, and #module_function will + now return their arguments. If a single argument is given, it + is returned. If no arguments are given, nil is returned. If + multiple arguments are given, they are returned as an array. + [[Feature #12495]] + +* Process + + * Process.\_fork is added. This is a core method for fork(2). + Do not call this method directly; it is called by existing + fork methods: Kernel.#fork, Process.fork, and IO.popen("-"). + Application monitoring libraries can overwrite this method to + hook fork events. [[Feature #17795]] + +* Struct + + * Passing only keyword arguments to Struct#initialize is warned. + You need to use a Hash literal to set a Hash to a first member. + [[Feature #16806]] + + * StructClass#keyword_init? is added [[Feature #18008]] + +* String + + * Update Unicode version to 13.0.0 [[Feature #17750]] + and Emoji version to 13.0 [[Feature #18029]] + + * String#unpack and String#unpack1 now accept an `offset:` keyword + argument to start the unpacking after an arbitrary number of bytes + have been skipped. If `offset` is outside of the string bounds + `ArgumentError` is raised. [[Feature #18254]] + +* Thread + + * Thread#native_thread_id is added. [[Feature #17853]] + +* Thread::Backtrace + + * Thread::Backtrace.limit, which returns the value to limit backtrace + length set by `--backtrace-limit` command line option, is added. + [[Feature #17479]] + +* Thread::Queue + + * Thread::Queue.new now accepts an Enumerable of initial values. + [[Feature #17327]] + +* Time + + * Time.new now accepts optional `in:` keyword argument for the + timezone, as well as `Time.at` and `Time.now`, so that is now + you can omit minor arguments to `Time.new`. [[Feature #17485]] + + ```ruby + Time.new(2021, 12, 25, in: "+07:00") + #=> 2021-12-25 00:00:00 +0700 + ``` + + At the same time, time component strings are converted to + integers more strictly now. + + ```ruby + Time.new(2021, 12, 25, "+07:30") + #=> invalid value for Integer(): "+07:30" (ArgumentError) + ``` + + Ruby 3.0 or earlier returned probably unexpected result + `2021-12-25 07:00:00`, not `2021-12-25 07:30:00` nor + `2021-12-25 00:00:00 +07:30`. + + * Time#strftime supports RFC 3339 UTC for unknown offset local + time, `-0000`, as `%-z`. [[Feature #17544]] + +* TracePoint + + * TracePoint.allow_reentry is added to allow reenter while TracePoint + callback. + [[Feature #15912]] + +* $LOAD_PATH + + * $LOAD_PATH.resolve_feature_path does not raise. [[Feature #16043]] + +* Fiber Scheduler + + * Add support for `Addrinfo.getaddrinfo` using `address_resolve` hook. + [[Feature #17370]] + + * Introduce non-blocking `Timeout.timeout` using `timeout_after` hook. + [[Feature #17470]] + + * Introduce new scheduler hooks `io_read` and `io_write` along with a + low level `IO::Buffer` for zero-copy read/write. [[Feature #18020]] + + * IO hooks `io_wait`, `io_read`, `io_write`, receive the original IO object + where possible. [[Bug #18003]] + + * Make `Monitor` fiber-safe. [[Bug #17827]] + + * Replace copy coroutine with pthread implementation. [[Feature #18015]] + +* Refinement + + * New class which represents a module created by Module#refine. + `include` and `prepend` are deprecated, and `import_methods` is added + instead. [[Bug #17429]] + +## Stdlib updates + +* The following default gem are updated. + * RubyGems 3.3.3 + * base64 0.1.1 + * benchmark 0.2.0 + * bigdecimal 3.1.1 + * bundler 2.3.3 + * cgi 0.3.1 + * csv 3.2.2 + * date 3.2.2 + * did_you_mean 1.6.1 + * digest 3.1.0 + * drb 2.1.0 + * erb 2.2.3 + * error_highlight 0.3.0 + * etc 1.3.0 + * fcntl 1.0.1 + * fiddle 1.1.0 + * fileutils 1.6.0 + * find 0.1.1 + * io-console 0.5.10 + * io-wait 0.2.1 + * ipaddr 1.2.3 + * irb 1.4.1 + * json 2.6.1 + * logger 1.5.0 + * net-http 0.2.0 + * net-protocol 0.1.2 + * nkf 0.1.1 + * open-uri 0.2.0 + * openssl 3.0.0 + * optparse 0.2.0 + * ostruct 0.5.2 + * pathname 0.2.0 + * pp 0.3.0 + * prettyprint 0.1.1 + * psych 4.0.3 + * racc 1.6.0 + * rdoc 6.4.0 + * readline 0.0.3 + * readline-ext 0.1.4 + * reline 0.3.0 + * resolv 0.2.1 + * rinda 0.1.1 + * ruby2_keywords 0.0.5 + * securerandom 0.1.1 + * set 1.0.2 + * stringio 3.0.1 + * strscan 3.0.1 + * tempfile 0.1.2 + * time 0.2.0 + * timeout 0.2.0 + * tmpdir 0.1.2 + * un 0.2.0 + * uri 0.11.0 + * yaml 0.2.0 + * zlib 2.1.1 +* The following bundled gems are updated. + * minitest 5.15.0 + * power_assert 2.0.1 + * rake 13.0.6 + * test-unit 3.5.3 + * rexml 3.2.5 + * rbs 2.0.0 + * typeprof 0.21.1 +* The following default gems are now bundled gems. + * net-ftp 0.1.3 + * net-imap 0.2.2 + * net-pop 0.1.1 + * net-smtp 0.3.1 + * matrix 0.4.2 + * prime 0.1.2 + * debug 1.4.0 + +* Coverage measurement now supports suspension. You can use `Coverage.suspend` + to stop the measurement temporarily, and `Coverage.resume` to restart it. + See [[Feature #18176]] in detail. + +* Random::Formatter is moved to random/formatter.rb, so that you can + use `Random#hex`, `Random#base64`, and so on without SecureRandom. + [[Feature #18190]] + +## Compatibility issues + +Note: Excluding feature bug fixes. + +* `rb_io_wait_readable`, `rb_io_wait_writable` and `rb_wait_for_single_fd` are + deprecated in favour of `rb_io_maybe_wait_readable`, + `rb_io_maybe_wait_writable` and `rb_io_maybe_wait` respectively. + `rb_thread_wait_fd` and `rb_thread_fd_writable` are deprecated. [[Bug #18003]] + +## Stdlib compatibility issues + +* `ERB#initialize` warns `safe_level` and later arguments even without -w. + [[Feature #14256]] + +* `lib/debug.rb` is replaced with `debug.gem` + +* `Kernel#pp` in `lib/pp.rb` uses the width of `IO#winsize` by default. + This means that the output width is automatically changed depending on + your terminal size. [[Feature #12913]] + +* Psych 4.0 changes `Psych.load` as `safe_load` by the default. + You may need to use Psych 3.3.2 for migrating to this behavior. + [[Bug #17866]] + +## C API updates + +* Documented. [[GH-4815]] + +* `rb_gc_force_recycle` is deprecated and has been changed to a no-op. + [[Feature #18290]] + +## Implementation improvements + +* Inline cache mechanism is introduced for reading class variables. + [[Feature #17763]] + +* `instance_eval` and `instance_exec` now only allocate a singleton class when + required, avoiding extra objects and improving performance. [[GH-5146]] + +* The performance of `Struct` accessors is improved. [[GH-5131]] + +* `mandatory_only?` builtin special form to improve performance on + builtin methods. [[GH-5112]] + +* Experimental feature Variable Width Allocation in the garbage collector. + This feature is turned off by default and can be enabled by compiling Ruby + with flag `USE_RVARGC=1` set. [[Feature #18045]] [[Feature #18239]] + +## JIT + +* Rename Ruby 3.0's `--jit` to `--mjit`, and alias `--jit` to `--yjit` + on non-Windows x86-64 platforms and to `--mjit` on others. + +### MJIT + +* The default `--mjit-max-cache` is changed from 100 to 10000. + +* JIT-ed code is no longer cancelled when a TracePoint for class events + is enabled. + +* The JIT compiler no longer skips compilation of methods longer than + 1000 instructions. + +* `--mjit-verbose` and `--mjit-warning` output "JIT cancel" when JIT-ed + code is disabled because TracePoint or GC.compact is used. + +### YJIT: New experimental in-process JIT compiler + +New JIT compiler available as an experimental feature. [[Feature #18229]] + +See [this blog post](https://shopify.engineering/yjit-just-in-time-compiler-cruby +) introducing the project. + +* Disabled by default, use `--yjit` command-line option to enable YJIT. + +* Performance improvements on benchmarks based on real-world software, + up to 22% on railsbench, 39% on liquid-render. + +* Fast warm-up times. + +* Limited to Unix-like x86-64 platforms for now. + +## Static analysis + +### RBS + +* Generics type parameters can be bounded ([PR](https://github.com/ruby/rbs/pull/844)). + + ```rbs + # `T` must be compatible with the `_Output` interface. + # `PrettyPrint[String]` is ok, but `PrettyPrint[Integer]` is a type error. + class PrettyPrint[T < _Output] + interface _Output + def <<: (String) -> void + end + + attr_reader output: T + + def initialize: (T output) -> void + end + ``` + +* Type aliases can be generic. ([PR](https://github.com/ruby/rbs/pull/823)) + + ```rbs + # Defines a generic type `list`. + type list[T] = [ T, list[T] ] + | nil + + type str_list = list[String] + type int_list = list[Integer] + ``` + +* [rbs collection](https://github.com/ruby/rbs/blob/master/docs/collection.md) has been introduced to manage gems’ RBSs. + +* Many signatures for built-in and standard libraries have been added/updated. + +* It includes many bug fixes and performance improvements too. + +See the [CHANGELOG.md](https://github.com/ruby/rbs/blob/master/CHANGELOG.md) for more information. + +### TypeProf + +* [Experimental IDE support](https://github.com/ruby/typeprof/blob/master/doc/ide.md) has been implemented. +* Many bug fixes and performance improvements since Ruby 3.0.0. + +## Debugger + +* A new debugger [debug.gem](https://github.com/ruby/debug) is bundled. + debug.gem is a fast debugger implementation, and it provides many features + like remote debugging, colorful REPL, IDE (VSCode) integration, and more. + It replaces `lib/debug.rb` standard library. + +* `rdbg` command is also installed into `bin/` directory to start and control + debugging execution. + +## error_highlight + +A built-in gem called error_highlight has been introduced. +It shows fine-grained error locations in the backtrace. + +Example: `title = json[:article][:title]` + +If `json` is nil, it shows: + +``` +$ ruby test.rb +test.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError) + +title = json[:article][:title] + ^^^^^^^^^^ +``` + +If `json[:article]` returns nil, it shows: + +``` +$ ruby test.rb +test.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError) + +title = json[:article][:title] + ^^^^^^^^ +``` + +This feature is enabled by default. +You can disable it by using a command-line option `--disable-error_highlight`. +See [the repository](https://github.com/ruby/error_highlight) in detail. + +## IRB Autocomplete and Document Display + +The IRB now has an autocomplete feature, where you can just type in the code, and the completion candidates dialog will appear. You can use Tab and Shift+Tab to move up and down. + +If documents are installed when you select a completion candidate, the documentation dialog will appear next to the completion candidates dialog, showing part of the content. You can read the full document by pressing Alt+d. + +## Miscellaneous changes + +* lib/objspace/trace.rb is added, which is a tool for tracing the object + allocation. Just by requiring this file, tracing is started *immediately*. + Just by `Kernel#p`, you can investigate where an object was created. + Note that just requiring this file brings a large performance overhead. + This is only for debugging purposes. Do not use this in production. + [[Feature #17762]] + +* Now exceptions raised in finalizers will be printed to `STDERR`, unless + `$VERBOSE` is `nil`. [[Feature #17798]] + +* `ruby -run -e httpd` displays URLs to access. [[Feature #17847]] + +* Add `ruby -run -e colorize` to colorize Ruby code using + `IRB::Color.colorize_code`. + +[Bug #4443]: https://bugs.ruby-lang.org/issues/4443 +[Feature #6210]: https://bugs.ruby-lang.org/issues/6210 +[Feature #10917]: https://bugs.ruby-lang.org/issues/10917 +[Feature #11256]: https://bugs.ruby-lang.org/issues/11256 +[Feature #11689]: https://bugs.ruby-lang.org/issues/11689 +[Feature #12194]: https://bugs.ruby-lang.org/issues/12194 +[Feature #12495]: https://bugs.ruby-lang.org/issues/12495 +[Feature #12913]: https://bugs.ruby-lang.org/issues/12913 +[Feature #14256]: https://bugs.ruby-lang.org/issues/14256 +[Feature #14579]: https://bugs.ruby-lang.org/issues/14579 +[Feature #15198]: https://bugs.ruby-lang.org/issues/15198 +[Feature #15211]: https://bugs.ruby-lang.org/issues/15211 +[Feature #15912]: https://bugs.ruby-lang.org/issues/15912 +[Feature #16043]: https://bugs.ruby-lang.org/issues/16043 +[Feature #16182]: https://bugs.ruby-lang.org/issues/16182 +[Feature #16806]: https://bugs.ruby-lang.org/issues/16806 +[Feature #17312]: https://bugs.ruby-lang.org/issues/17312 +[Feature #17327]: https://bugs.ruby-lang.org/issues/17327 +[Feature #17370]: https://bugs.ruby-lang.org/issues/17370 +[Feature #17398]: https://bugs.ruby-lang.org/issues/17398 +[Feature #17411]: https://bugs.ruby-lang.org/issues/17411 +[Bug #17423]: https://bugs.ruby-lang.org/issues/17423 +[Bug #17429]: https://bugs.ruby-lang.org/issues/17429 +[Feature #17470]: https://bugs.ruby-lang.org/issues/17470 +[Feature #17479]: https://bugs.ruby-lang.org/issues/17479 +[Feature #17485]: https://bugs.ruby-lang.org/issues/17485 +[Feature #17544]: https://bugs.ruby-lang.org/issues/17544 +[Feature #17592]: https://bugs.ruby-lang.org/issues/17592 +[Feature #17684]: https://bugs.ruby-lang.org/issues/17684 +[Feature #17724]: https://bugs.ruby-lang.org/issues/17724 +[Feature #17744]: https://bugs.ruby-lang.org/issues/17744 +[Feature #17750]: https://bugs.ruby-lang.org/issues/17750 +[Feature #17762]: https://bugs.ruby-lang.org/issues/17762 +[Feature #17763]: https://bugs.ruby-lang.org/issues/17763 +[Feature #17795]: https://bugs.ruby-lang.org/issues/17795 +[Feature #17798]: https://bugs.ruby-lang.org/issues/17798 +[Bug #17827]: https://bugs.ruby-lang.org/issues/17827 +[Feature #17847]: https://bugs.ruby-lang.org/issues/17847 +[Feature #17853]: https://bugs.ruby-lang.org/issues/17853 +[Bug #17866]: https://bugs.ruby-lang.org/issues/17866 +[Bug #18003]: https://bugs.ruby-lang.org/issues/18003 +[Feature #18008]: https://bugs.ruby-lang.org/issues/18008 +[Feature #18015]: https://bugs.ruby-lang.org/issues/18015 +[Feature #18020]: https://bugs.ruby-lang.org/issues/18020 +[Feature #18029]: https://bugs.ruby-lang.org/issues/18029 +[Feature #18045]: https://bugs.ruby-lang.org/issues/18045 +[Feature #18148]: https://bugs.ruby-lang.org/issues/18148 +[Feature #18172]: https://bugs.ruby-lang.org/issues/18172 +[Feature #18176]: https://bugs.ruby-lang.org/issues/18176 +[Feature #18190]: https://bugs.ruby-lang.org/issues/18190 +[Feature #18229]: https://bugs.ruby-lang.org/issues/18229 +[Feature #18239]: https://bugs.ruby-lang.org/issues/18239 +[Feature #18254]: https://bugs.ruby-lang.org/issues/18254 +[Feature #18273]: https://bugs.ruby-lang.org/issues/18273 +[Feature #18290]: https://bugs.ruby-lang.org/issues/18290 + +[GH-1509]: https://github.com/ruby/ruby/pull/1509 +[GH-4815]: https://github.com/ruby/ruby/pull/4815 +[GH-5112]: https://github.com/ruby/ruby/pull/5112 +[GH-5131]: https://github.com/ruby/ruby/pull/5131 +[GH-5146]: https://github.com/ruby/ruby/pull/5146 |