From 3096baec0e4c24e325885f7dcd4956e8c0421f73 Mon Sep 17 00:00:00 2001 From: Kazuhiro NISHIYAMA Date: Tue, 31 Dec 2019 18:16:21 +0900 Subject: [PATCH] Copy NEWS to doc/NEWS-2.7.0 --- doc/NEWS-2.7.0 | 828 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 828 insertions(+) create mode 100644 doc/NEWS-2.7.0 diff --git a/doc/NEWS-2.7.0 b/doc/NEWS-2.7.0 new file mode 100644 index 0000000000..4ff6cf09dc --- /dev/null +++ b/doc/NEWS-2.7.0 @@ -0,0 +1,828 @@ +# -*- rdoc -*- + += NEWS for Ruby 2.7.0 + +This document is a list of user visible feature changes made between +releases 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). + +== Changes since the 2.6.0 release + +=== Language changes + +==== Pattern matching + +* Pattern matching is introduced as an experimental feature. [Feature #14912] + + case [0, [1, 2, 3]] + in [a, [b, *c]] + p a #=> 0 + p b #=> 1 + p c #=> [2, 3] + end + + case {a: 0, b: 1} + in {a: 0, x: 1} + :unreachable + in {a: 0, b: var} + p var #=> 1 + end + + case -1 + in 0 then :unreachable + in 1 then :unreachable + end #=> NoMatchingPatternError + + json = < "Bob" + p age #=> 2 + + JSON.parse(json, symbolize_names: true) in {name: "Alice", children: [{name: "Charlie", age: age}]} + #=> NoMatchingPatternError + +* See the following slides for more details: + * https://speakerdeck.com/k_tsj/pattern-matching-new-feature-in-ruby-2-dot-7 + * Note that the slides are slightly obsolete. + +* The warning against pattern matching can be suppressed with + {-W:no-experimental option}[#label-Warning+option]. + +==== The spec of keyword arguments is changed towards 3.0 + +* Automatic conversion of keyword arguments and positional arguments is + deprecated, and conversion will be removed in Ruby 3. [Feature #14183] + + * When a method call passes a Hash at the last argument, and when it + passes no keywords, and when the called method accepts keywords, + a warning is emitted. To continue treating the hash as keywords, + add a double splat operator to avoid the warning and ensure + correct behavior in Ruby 3. + + def foo(key: 42); end; foo({key: 42}) # warned + def foo(**kw); end; foo({key: 42}) # warned + def foo(key: 42); end; foo(**{key: 42}) # OK + def foo(**kw); end; foo(**{key: 42}) # OK + + * When a method call passes keywords to a method that accepts keywords, + but it does not pass enough required positional arguments, the + keywords are treated as a final required positional argument, and a + warning is emitted. Pass the argument as a hash instead of keywords + to avoid the warning and ensure correct behavior in Ruby 3. + + def foo(h, **kw); end; foo(key: 42) # warned + def foo(h, key: 42); end; foo(key: 42) # warned + def foo(h, **kw); end; foo({key: 42}) # OK + def foo(h, key: 42); end; foo({key: 42}) # OK + + * When a method accepts specific keywords but not a keyword splat, and + a hash or keywords splat is passed to the method that includes both + Symbol and non-Symbol keys, the hash will continue to be split, and + a warning will be emitted. You will need to update the calling code + to pass separate hashes to ensure correct behavior in Ruby 3. + + def foo(h={}, key: 42); end; foo("key" => 43, key: 42) # warned + def foo(h={}, key: 42); end; foo({"key" => 43, key: 42}) # warned + def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK + + * If a method does not accept keywords, and is called with keywords, + the keywords are still treated as a positional hash, with no warning. + This behavior will continue to work in Ruby 3. + + def foo(opt={}); end; foo( key: 42 ) # OK + +* Non-symbols are allowed as keyword argument keys if the method accepts + arbitrary keywords. [Feature #14183] + + * Non-Symbol keys in a keyword arguments hash were prohibited in 2.6.0, + but are now allowed again. [Bug #15658] + + def foo(**kw); p kw; end; foo("str" => 1) #=> {"str"=>1} + +* **nil is allowed in method definitions to explicitly mark + that the method accepts no keywords. Calling such a method with keywords + will result in an ArgumentError. [Feature #14183] + + def foo(h, **nil); end; foo(key: 1) # ArgumentError + def foo(h, **nil); end; foo(**{key: 1}) # ArgumentError + def foo(h, **nil); end; foo("str" => 1) # ArgumentError + def foo(h, **nil); end; foo({key: 1}) # OK + def foo(h, **nil); end; foo({"str" => 1}) # OK + +* Passing an empty keyword splat to a method that does not accept keywords + no longer passes an empty hash, unless the empty hash is necessary for + a required parameter, in which case a warning will be emitted. Remove + the double splat to continue passing a positional hash. [Feature #14183] + + h = {}; def foo(*a) a end; foo(**h) # [] + h = {}; def foo(a) a end; foo(**h) # {} and warning + h = {}; def foo(*a) a end; foo(h) # [{}] + h = {}; def foo(a) a end; foo(h) # {} + +* Above warnings can be suppressed also with {-W:no-deprecated option}[#label-Warning+option]. + +==== Numbered parameters + +* Numbered parameters as default block parameters are introduced. + [Feature #4475] + + [1, 2, 10].map { _1.to_s(16) } #=> ["1", "2", "a"] + [[1, 2], [3, 4]].map { _1 + _2 } #=> [3, 7] + + You can still define a local variable named +_1+ and so on, + and that is honored when present, but renders a warning. + + _1 = 0 #=> warning: `_1' is reserved for numbered parameter; consider another name + [1].each { p _1 } # prints 0 instead of 1 + +==== proc/lambda without block is deprecated + +* Proc.new and Kernel#proc with no block in a method called with a block will + now display a warning. + + def foo + proc + end + foo { puts "Hello" } #=> warning: Capturing the given block using Kernel#proc is deprecated; use `&block` instead + + This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option]. + +* Kernel#lambda with no block in a method called with a block raises an exception. + + def bar + lambda + end + bar { puts "Hello" } #=> tried to create Proc object without a block (ArgumentError) + +==== Other miscellaneous changes + +* A beginless range is experimentally introduced. It might be useful + in +case+, new call-sequence of the Comparable#clamp, + constants and DSLs. [Feature #14799] + + ary[..3] # identical to ary[0..3] + + case RUBY_VERSION + when ..."2.4" then puts "EOL" + # ... + end + + age.clamp(..100) + + where(sales: ..100) + +* Setting $; to a non-nil value will now display a warning. [Feature #14240] + This includes the usage in String#split. + This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option]. + +* Setting $, to a non-nil value will now display a warning. [Feature #14240] + This include the usage in Array#join. + This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option]. + +* Quoted here-document identifiers must end within the same line. + + <<"EOS + " # This had been warned since 2.4; Now it raises a SyntaxError + EOS + +* The flip-flop syntax deprecation is reverted. [Feature #5400] + +* Comment lines can be placed between fluent dot now. + + foo + # .bar + .baz # => foo.baz + +* Calling a private method with a literal +self+ as the receiver + is now allowed. [Feature #11297] [Feature #16123] + +* Modifier rescue now operates the same for multiple assignment as single + assignment. [Bug #8279] + + a, b = raise rescue [1, 2] + # Previously parsed as: (a, b = raise) rescue [1, 2] + # Now parsed as: a, b = (raise rescue [1, 2]) + +* +yield+ in singleton class syntax will now display a warning. This behavior + will soon be deprecated. [Feature #15575]. + + def foo + class << Object.new + yield #=> warning: `yield' in class syntax will not be supported from Ruby 3.0. [Feature #15575] + end + end + foo { p :ok } + + This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option]. + +* Argument forwarding by (...) is introduced. [Feature #16253] + + def foo(...) + bar(...) + end + + All arguments to +foo+ are forwarded to +bar+, including keyword and + block arguments. + Note that the parentheses are mandatory. bar ... is parsed + as an endless range. + +* Access and setting of $SAFE will now always display a warning. + $SAFE will become a normal global variable in Ruby 3.0. + [Feature #16131] + +* Object#{taint,untaint,trust,untrust} and related functions in the C-API + no longer have an effect (all objects are always considered untainted), and will now + display a warning in verbose mode. This warning will be disabled even in non-verbose mode in + Ruby 3.0, and the methods and C functions will be removed in Ruby 3.2. [Feature #16131] + +* Refinements take place at Object#method and Module#instance_method. [Feature #15373] + +=== Command line options + +==== Warning option + +The +-W+ option has been extended with a following +:+, to manage categorized +warnings. [Feature #16345] [Feature #16420] + +* To suppress deprecation warnings: + + $ ruby -e '$; = ""' + -e:1: warning: `$;' is deprecated + + $ ruby -W:no-deprecated -e '$; = //' + +* It works with the +RUBYOPT+ environment variable: + + $ RUBYOPT=-W:no-deprecated ruby -e '$; = //' + +* To suppress experimental feature warnings: + + $ ruby -e '0 in a' + -e:1: warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby! + + $ ruby -W:no-experimental -e '0 in a' + +* To suppress both by using +RUBYOPT+, set space separated values: + + $ RUBYOPT='-W:no-deprecated -W:no-experimental' ruby -e '($; = "") in a' + +See also Warning in {Core classes updates}[#label-Core+classes+updates+-28outstanding+ones+only-29]. + +=== Core classes updates (outstanding ones only) + +Array:: + + New methods:: + + * Added Array#intersection. [Feature #16155] + + * Added Array#minmax, with a faster implementation than Enumerable#minmax. [Bug #15929] + +Comparable:: + + Modified method:: + + * Comparable#clamp now accepts a Range argument. [Feature #14784] + + -1.clamp(0..2) #=> 0 + 1.clamp(0..2) #=> 1 + 3.clamp(0..2) #=> 2 + # With beginless and endless ranges: + -1.clamp(0..) #=> 0 + 3.clamp(..2) #=> 2 + + +Complex:: + + New method:: + + * Added Complex#<=>. + So 0 <=> 0i will not raise NoMethodError. [Bug #15857] + +Dir:: + + Modified methods:: + + * Dir.glob and Dir.[] no longer allow NUL-separated glob pattern. + Use Array instead. [Feature #14643] + +Encoding:: + + New encoding:: + + * Added new encoding CESU-8. [Feature #15931] + +Enumerable:: + + New methods:: + + * Added Enumerable#filter_map. [Feature #15323] + + [1, 2, 3].filter_map {|x| x.odd? ? x.to_s : nil } #=> ["1", "3"] + + * Added Enumerable#tally. [Feature #11076] + + ["A", "B", "C", "B", "A"].tally #=> {"A"=>2, "B"=>2, "C"=>1} + +Enumerator:: + + New methods:: + + * Added Enumerator.produce to generate an Enumerator from any custom + data transformation. [Feature #14781] + + require "date" + dates = Enumerator.produce(Date.today, &:succ) #=> infinite sequence of dates + dates.detect(&:tuesday?) #=> next Tuesday + + * Added Enumerator::Lazy#eager that generates a non-lazy enumerator + from a lazy enumerator. [Feature #15901] + + a = %w(foo bar baz) + e = a.lazy.map {|x| x.upcase }.map {|x| x + "!" }.eager + p e.class #=> Enumerator + p e.map {|x| x + "?" } #=> ["FOO!?", "BAR!?", "BAZ!?"] + + * Added Enumerator::Yielder#to_proc so that a Yielder object + can be directly passed to another method as a block + argument. [Feature #15618] + +Fiber:: + + New method:: + + * Added Fiber#raise that behaves like Fiber#resume but raises an + exception on the resumed fiber. [Feature #10344] + +File:: + + Modified method:: + + * File.extname now returns a dot string for names ending with a dot on + non-Windows platforms. [Bug #15267] + + File.extname("foo.") #=> "." + +FrozenError:: + + New method:: + + * Added FrozenError#receiver to return the frozen object on which + modification was attempted. To set this object when raising + FrozenError in Ruby code, FrozenError.new accepts a +:receiver+ + option. [Feature #15751] + +GC:: + + New method:: + + * Added GC.compact method for compacting the heap. + This function compacts live objects in the heap so that fewer pages may + be used, and the heap may be more CoW (copy-on-write) friendly. [Feature #15626] + + Details on the algorithm and caveats can be found here: + https://bugs.ruby-lang.org/issues/15626 + +IO:: + + New method:: + + * Added IO#set_encoding_by_bom to check the BOM and set the external + encoding. [Bug #15210] + +Integer:: + + Modified method:: + + * Integer#[] now supports range operations. [Feature #8842] + + 0b01001101[2, 4] #=> 0b0011 + 0b01001100[2..5] #=> 0b0011 + 0b01001100[2...6] #=> 0b0011 + # ^^^^ + +Method:: + + Modified method:: + + * Method#inspect shows more information. [Feature #14145] + +Module:: + + New methods:: + + * Added Module#const_source_location to retrieve the location where a + constant is defined. [Feature #10771] + + * Added Module#ruby2_keywords for marking a method as passing keyword + arguments through a regular argument splat, useful when delegating + all arguments to another method in a way that can be backwards + compatible with older Ruby versions. [Bug #16154] + + Modified methods:: + + * Module#autoload? now takes an +inherit+ optional argument, like + Module#const_defined?. [Feature #15777] + + * Module#name now always returns a frozen String. The returned String is + always the same for a given Module. This change is + experimental. [Feature #16150] + +NilClass / TrueClass / FalseClass:: + + Modified methods:: + + * NilClass#to_s, TrueClass#to_s, and FalseClass#to_s now always return a + frozen String. The returned String is always the same for each of these + values. This change is experimental. [Feature #16150] + +ObjectSpace::WeakMap:: + + Modified method:: + + * ObjectSpace::WeakMap#[]= now accepts special objects as either key or + values. [Feature #16035] + +Proc:: + + New method:: + + * Added Proc#ruby2_keywords for marking the proc as passing keyword + arguments through a regular argument splat, useful when delegating + all arguments to another method or proc in a way that can be backwards + compatible with older Ruby versions. [Feature #16404] + +Range:: + + New method:: + + * Added Range#minmax, with a faster implementation than Enumerable#minmax. + It returns a maximum that now corresponds to Range#max. [Bug #15807] + + Modified method:: + + * Range#=== now uses Range#cover? for String arguments, too (in Ruby 2.6, it was + changed from Range#include? for all types except strings). [Bug #15449] + + +RubyVM:: + + Removed method:: + + * +RubyVM.resolve_feature_path+ moved to + $LOAD_PATH.resolve_feature_path. [Feature #15903] [Feature #15230] + +String:: + + Unicode:: + + * Update Unicode version and Emoji version from 11.0.0 to + 12.0.0. [Feature #15321] + + * Update Unicode version to 12.1.0, adding support for + U+32FF SQUARE ERA NAME REIWA. [Feature #15195] + + * Update Unicode Emoji version to 12.1. [Feature #16272] + +Symbol:: + + New methods:: + + * Added Symbol#start_with? and Symbol#end_with? methods. [Feature #16348] + +Time:: + + New methods:: + + * Added Time#ceil method. [Feature #15772] + + * Added Time#floor method. [Feature #15653] + + Modified method:: + + * Time#inspect is separated from Time#to_s and it shows + the time's sub second. [Feature #15958] + +UnboundMethod:: + + New method:: + + * Added UnboundMethod#bind_call method. [Feature #15955] + + umethod.bind_call(obj, ...) is semantically equivalent + to umethod.bind(obj).call(...). This idiom is used in + some libraries to call a method that is overridden. The added + method does the same without allocation of an intermediate Method + object. + + class Foo + def add_1(x) + x + 1 + end + end + class Bar < Foo + def add_1(x) # override + x + 2 + end + end + + obj = Bar.new + p obj.add_1(1) #=> 3 + p Foo.instance_method(:add_1).bind(obj).call(1) #=> 2 + p Foo.instance_method(:add_1).bind_call(obj, 1) #=> 2 + +Warning:: + + New methods:: + + * Added Warning.[] and Warning.[]= to manage emitting/suppressing + some categories of warnings. [Feature #16345] [Feature #16420] + +$LOAD_PATH:: + + New method:: + + * Added $LOAD_PATH.resolve_feature_path. [Feature #15903] [Feature #15230] + +=== Stdlib updates (outstanding ones only) + +Bundler:: + + * Upgrade to Bundler 2.1.2. + See https://github.com/bundler/bundler/releases/tag/v2.1.2 + +CGI:: + + * CGI.escapeHTML becomes 2~5x faster when there is at least one escaped character. + See https://github.com/ruby/ruby/pull/2226 + +CSV:: + + * Upgrade to 3.1.2. + See https://github.com/ruby/csv/blob/master/NEWS.md. + +Date:: + + * Date.jisx0301, Date#jisx0301, and Date.parse support the new Japanese + era. [Feature #15742] + +Delegator:: + + * Object#DelegateClass accepts a block and module_evals it in the context + of the returned class, similar to Class.new and Struct.new. + +ERB:: + + * Prohibit marshaling ERB instance. + +IRB:: + + * Introduce syntax highlighting inspired by the Pry gem to Binding#irb + source lines, REPL input, and inspect output of some core-class objects. + + * Introduce multiline editing mode provided by Reline. + + * Show documentation when completion. + + * Enable auto indent and save/load history by default. + +JSON:: + + * Upgrade to 2.3.0. + +Net::FTP:: + + * Add Net::FTP#features to check available features, and Net::FTP#option to + enable/disable each of them. [Feature #15964] + +Net::HTTP:: + + * Add +ipaddr+ optional parameter to Net::HTTP#start to replace the address for + the TCP/IP connection. [Feature #5180] + +Net::IMAP:: + + * Add Server Name Indication (SNI) support. [Feature #15594] + +open-uri:: + + * Warn open-uri's "open" method at Kernel. + Use URI.open instead. [Misc #15893] + + * The default charset of "text/*" media type is UTF-8 instead of + ISO-8859-1. [Bug #15933] + +OptionParser:: + + * Now show "Did you mean?" for unknown options. [Feature #16256] + + test.rb: + + require "optparse" + OptionParser.new do |opts| + opts.on("-f", "--foo", "foo") {|v| } + opts.on("-b", "--bar", "bar") {|v| } + opts.on("-c", "--baz", "baz") {|v| } + end.parse! + + example: + + $ ruby test.rb --baa + Traceback (most recent call last): + test.rb:7:in `
': invalid option: --baa (OptionParser::InvalidOption) + Did you mean? baz + bar + +Pathname:: + + * Pathname.glob now delegates 3 arguments to Dir.glob + to accept +base+ keyword. [Feature #14405] + +Racc:: + + * Merge 1.4.15 from upstream repository and added cli of racc. + +Reline:: + + * New stdlib that is compatible with the readline stdlib but is + implemented in pure Ruby. It also provides a multiline editing mode. + +REXML:: + + * Upgrade to 3.2.3. + See https://github.com/ruby/rexml/blob/master/NEWS.md. + +RSS:: + + * Upgrade to RSS 0.2.8. + See https://github.com/ruby/rss/blob/master/NEWS.md. + +RubyGems:: + + * Upgrade to RubyGems 3.1.2. + * https://github.com/rubygems/rubygems/releases/tag/v3.1.0 + * https://github.com/rubygems/rubygems/releases/tag/v3.1.1 + * https://github.com/rubygems/rubygems/releases/tag/v3.1.2 + +StringScanner:: + + * Upgrade to 1.0.3. + See https://github.com/ruby/strscan/blob/master/NEWS.md. + +=== Compatibility issues (excluding feature bug fixes) + +* The following libraries are no longer bundled gems. + Install corresponding gems to use these features. + * CMath (cmath gem) + * Scanf (scanf gem) + * Shell (shell gem) + * Synchronizer (sync gem) + * ThreadsWait (thwait gem) + * E2MM (e2mmap gem) + +Proc:: + * The Proc#to_s format was changed. [Feature #16101] + +Range:: + * Range#minmax used to iterate on the range to determine the maximum. + It now uses the same algorithm as Range#max. In rare cases (e.g. + ranges of Floats or Strings), this may yield different results. [Bug #15807] + +=== Stdlib compatibility issues (excluding feature bug fixes) + +* Promote stdlib to default gems + * The following default gems were published on rubygems.org + * benchmark + * cgi + * delegate + * getoptlong + * net-pop + * net-smtp + * open3 + * pstore + * readline + * readline-ext + * singleton + * The following default gems were only promoted at ruby-core, + but not yet published on rubygems.org. + * monitor + * observer + * timeout + * tracer + * uri + * yaml +* The did_you_mean gem has been promoted up to a default gem from a bundled gem + +pathname:: + + * Kernel#Pathname when called with a Pathname argument now returns + the argument instead of creating a new Pathname. This is more + similar to other Kernel methods, but can break code that modifies + the return value and expects the argument not to be modified. + +profile.rb, Profiler__:: + + * Removed from standard library. It was unmaintained since Ruby 2.0.0. + +=== C API updates + +* Many *_kw functions have been added for setting whether + the final argument being passed should be treated as keywords. You + may need to switch to these functions to avoid keyword argument + separation warnings, and to ensure correct behavior in Ruby 3. + +* The : character in rb_scan_args format string is now + treated as keyword arguments. Passing a positional hash instead of + keyword arguments will emit a deprecation warning. + +* C API declarations with +ANYARGS+ are changed not to use +ANYARGS+. + See https://github.com/ruby/ruby/pull/2404 + +=== Implementation improvements + +Fiber:: + + * Allow selecting different coroutine implementations by using + +--with-coroutine=+, e.g. + + $ ./configure --with-coroutine=ucontext + $ ./configure --with-coroutine=copy + + * Replace previous stack cache with fiber pool cache. The fiber pool + allocates many stacks in a single memory region. Stack allocation + becomes O(log N) and fiber creation is amortized O(1). Around 10x + performance improvement was measured in micro-benchmarks. + https://github.com/ruby/ruby/pull/2224 + +File:: + * File.realpath now uses realpath(3) on many platforms, which can + significantly improve performance. [Feature #15797] + +Hash:: + * Change data structure of small Hash objects. [Feature #15602] + +Monitor:: + * Monitor class is written in C-extension. [Feature #16255] + +Thread:: + + * VM stack memory allocation is now combined with native thread stack, + improving thread allocation performance and reducing allocation related + failures. Around 10x performance improvement was measured in micro-benchmarks. + +JIT:: + + * JIT-ed code is recompiled to less-optimized code when an optimization assumption is invalidated. + + * Method inlining is performed when a method is considered as pure. + This optimization is still experimental and many methods are NOT considered as pure yet. + + * The default value of +--jit-max-cache+ is changed from 1,000 to 100. + + * The default value of +--jit-min-calls+ is changed from 5 to 10,000. + +RubyVM:: + + * Per-call-site method cache, which has been there since around 1.9, was + improved: cache hit rate raised from 89% to 94%. + See https://github.com/ruby/ruby/pull/2583 + +RubyVM::InstructionSequence:: + + * RubyVM::InstructionSequence#to_binary method generates compiled binary. + The binary size is reduced. [Feature #16163] + +=== Miscellaneous changes + +* Support for IA64 architecture has been removed. Hardware for testing was + difficult to find, native fiber code is difficult to implement, and it added + non-trivial complexity to the interpreter. [Feature #15894] + +* Require compilers to support C99. [Misc #15347] + + * Details of our dialect: https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/C99 + +* Ruby's upstream repository is changed from Subversion to Git. + + * https://git.ruby-lang.org/ruby.git + + * RUBY_REVISION class is changed from Integer to String. + + * RUBY_DESCRIPTION includes Git revision instead of Subversion's one. + +* Support built-in methods in Ruby with the _\_builtin_ syntax. [Feature #16254] + + Some methods are defined in *.rb (such as trace_point.rb). + For example, it is easy to define a method which accepts keyword arguments.