NEWS for Ruby 2.3.0

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 2.2.0 release

Language changes

• frozen-string-literal pragma:

  • new pragma, frozen-string-literal has been experimentally introduced.

    Feature #8976

  • besides, –enable/–disable=frozen-string-literal options also have been introduced. [Feature #8976]

  • command line options –debug or –debug=frozen-string-literal enable additional debugging mode which shows created location with at frozen object error (RuntimeError).

    Feature #11725

• safe navigation operator:

  • new method call syntax, `object&.foo', method #foo is called on `object' if it is not nil. this is similar to `try!' in Active Support, except:

    • method name is syntactically required

      obj.try! {} # valid
      obj&. {}    # syntax error

    • arguments are evaluated only if a call is made:

      obj.try!(:foo, bar())  # bar() is always evaluated
      obj&.foo(bar())        # bar() is conditionally evaluated

    • attribute assignment is valid

      obj&.attr += 1

    Feature #11537

• the did_you_mean gem:

  • When a NameError or NoMethodError occurs because of a typo in the name, the did_you_mean gem automatically suggests other names similar to the method name.

    "Yuki".starts_with?("Y")
    # => NoMethodError: undefined method `starts_with?' for "Yuki":String
    #    Did you mean?  start_with?

• indented here document:

  • new string literal, here document starts with <<~. refer doc/syntax/literals.rdoc for more details.

    Feature #9098

Core classes updates (outstanding ones only)

• ARGF

  • ARGF.read_nonblock supports `exception: false' like IO#read_nonblock.

    Feature #11358

• Array

  • Array#bsearch_index [Feature #10730]

  • Array#dig [Feature #11643]

• Comparable

  • Comparable#== no longer rescues exceptions [Feature #7688]

• Encoding

  • new Encoding::IBM037 (alias ebcdic-cp-us; dummy)

• Enumerable

  • Enumerable#grep_v is added as inverse version of Enumerable#grep.

    Feature #11049

  • Enumerable#chunk_while [Feature #10769]

• Enumerator::Lazy

  • Enumerator::Lazy#grep_v [Feature #11773]

• File

  • File.mkfifo [Feature #11536]

  • Add File::TMPFILE corresponding to O_TMPFILE

• Hash

  • Hash#fetch_values [Feature #10017]

  • Hash#dig [Feature #11643]

  • Hash#<=, Hash#<, Hash#>=, Hash#> [Feature #10984]

  • Hash#to_proc [Feature #11653]

• IO

  • new mode flag File::SHARE_DELETE is available. this flag means to permit deleting opened file on Windows, but currently this affect only files opened as binary. [Feature #11218]

  • new option parameter `flags' is added. this parameter is bitwise-ORed to oflags generated by normal mode argument.

    Feature #11253

  • IO#advise no longer raises Errno::ENOSYS in cases where it was detected at build time but not available at runtime. [Feature #11806]

• Kernel

  • Kernel#loop, when stopped by a StopIteration exception, returns what the enumerator has returned instead of nil. [Feature #11498]

• Module

  • Module#deprecate_constant [Feature #11398]

• NameError

  • NameError#receiver is added to take the receiver object. [Feature #10881]

• Numeric

  • Numeric#positive? and Numeric#negative? are added, which return true when the receiver is positive and negative respectively.

    Feature #11151

• Proc

  • Proc#call (and also #[], #===, #yield) are optimized. Backtrace doesn't show each method (show block lines directly). TracePoint also ignores these calls. [Feature #11569]

• Queue (Thread::Queue)

  • Queue#close is added to notice a termination. [Feature #10600]

• Regexp/String: Updated Unicode version from 7.0.0 to 8.0.0

• RubyVM::InstructionSequence

  • add the following methods as a primitive tool of iseq loader. See sample/iseq_loader.rb for usage. Note that loader does not have verifier so it is easy to cause critical problem by loading modified/broken binary data. See [Feature #11788] for more details. (experimental feature)

    • RubyVM::InstructionSequence#to_binary(extra_data = nil)

    • RubyVM::InstructionSequence.load_from_binary(binary)

    • RubyVM::InstructionSequence.load_from_binary_extra_data(binary)

• String

  • String#+@ and String#-@ are added to get mutable/frozen strings.

    Feature #11782

  • String.new now accepts new option parameter `encoding'.

    Feature #11785

• Struct

  • Struct#dig [Feature #11688]

• Thread

  • Thread#name, Thread#name= are added to handle thread names [Feature #11251]

Core classes compatibility issues (excluding feature bug fixes)

• Array

  • Array#select!, Array#keep_if, Array#reject!, and Array#delete_if no longer changes the receiver array instantly every time the block is called. [Feature #10714]

  • Array#flatten and Array#flatten! no longer try to call #to_ary method on elements beyond the given level. [Bug #10748]

  • Array#inspect doesn't raise error even if its content returns a string which is not compatible with Encoding.default_external as inspected result. [Feature #11801]

• Enumerable

  • Enumerable#chunk and Enumerable#slice_before no longer takes the initial_state argument. [Feature #10958] Use a local variable instead to maintain a state.

• File::Stat

  • On Windows File::Stat#ino always returned 0, but now returns BY_HANDLE_FILE_INFORMATION.nFileIndexHigh/Low. [Feature #11216]

• Hash

  • Hash#inspect doesn't raise error even if its content returns a string which is not compatible with Encoding.default_external as inspected result. [Feature #11801]

• IO

  • IO#close doesn't raise when the IO object is closed. [Feature #10718]

  • IO#each_codepoint raises an exception at incomplete character before EOF when conversion takes place. [Bug #11444]

• Module

  • Module#define_method and Object.define_singleton_method now require method body, Proc, Method, or a block, and raise ArgumentError if no block is given directly. [Bug #11283]

• pack/unpack (Array/String)

  • j and J directives for pointer width integer type. [Feature #11215]

Stdlib updates (outstanding ones only)

• Logger

  • Logger#level= now supports symbol and string levels such as :debug, :info, :warn, :error, :fatal (case insensitive) [Feature #11695]

  • Logger#reopen is added to reopen a log device. [Feature #11696]

• io/wait

  • IO#wait_readable no longer checks FIONREAD, it may be used for non-bytestream IO such as listen sockets.

• Net::FTP

  • Net::FTP#mlst is added.

  • Net::FTP#mlsd is added.

• nkf

  • Merge nkf 2.1.4.

• ObjectSpace (objspace)

  • ObjectSpace.count_symbols is added.

  • ObjectSpace.count_imemo_objects is added.

  • ObjectSpace.internal_class_of is added.

  • ObjectSpace.internal_super_of is added.

• OpenSSL

  • OpenSSL::SSL::SSLSocket#accept_nonblock and OpenSSL::SSL::SSLSocket#connect_nonblock supports `exception: false`.

    Feature #10532

• Pathname

  • Pathname#descend and Pathname#ascend supported blockless form.

    Feature #11052

• Socket

  • Socket#connect_nonblock, Socket#accept_nonblock, TCPServer#accept_nonblock, UNIXServer#accept_nonblock, BasicSocket#recv_nonblock, BasicSocket#recvmsg_nonblock, BasicSocket#sendmsg_nonblock all support `exception: false` to return :wait_readable or :wait_writable symbols instead of raising IO::WaitReadable or IO::WaitWritable exceptions

    Feature #10532

    Feature #11229

  • BasicSocket#recv and BasicSocket#recv_nonblock allow an output String buffer argument like IO#read and IO#read_nonblock to reduce GC overhead [Feature #11242]

• StringIO

  • In read-only mode, StringIO#set_encoding no longer sets the encoding of its buffer string. Setting the encoding of the string directly without StringIO#set_encoding may cause unpredictable behavior now.

    Bug #11827

• timeout

  • Object#timeout is now warned as deprecated when called.

Stdlib compatibility issues (excluding feature bug fixes)

• ext/coverage/coverage.c

  • Coverage.peek_result: new method to allow coverage to be captured without stopping the coverage tool. [Feature #10816]

• Fiddle

  • Fiddle::Function#call releases the GVL. [Feature #11607]

• io-console

  • Update to io-console 0.4.5, and change the license to BSD 2-clause “Simplified” License.

• lib/base64.rb

  • Base64.urlsafe_encode64: added a “padding” option to suppress the padding character (“=”). [Feature #10740]

  • Base64.urlsafe_decode64: now it accepts not only correctly-padded input but also unpadded input. [Feature #10740]

• lib/drb/drb.rb

  • removed unused argument. github.com/ruby/ruby/pull/515

• lib/matrix.rb

  • Add Vector#round. github.com/ruby/ruby/pull/802

• lib/webrick/utils.rb

  • removed unused argument. github.com/ruby/ruby/pull/356

• Net::FTP

  • Connections are in passive mode per default now. The default mode can be changed by Net::FTP.default_passive=. [Feature #11612]

• Net::HTTP

  • default value of Net::HTTP#open_timeout is now 60 (was nil).

• Net::Telnet

  • Net::Telnet is extracted to net-telnet gem. It's unmaintain code.

    Feature #11083

• Psych

  • Updated to Psych 2.0.17

• Rake

  • Rake is removed from stdlib. [Feature #11025]

• RDoc

  • Updated to RDoc 4.2.1. For full release notes see:

    github.com/rdoc/rdoc/blob/master/History.rdoc#421–2015-12-22

• RubyGems

  • Updated to RubyGems 2.5.1. For full release notes see:

    docs.seattlerb.org/rubygems/History_txt.html#label-2.5.0+-2F+2015-11-03 and docs.seattlerb.org/rubygems/History_txt.html#label-2.5.1+-2F+2015-12-10

Built-in global variables compatibility issues

• $SAFE

  • $SAFE=2 and $SAFE=3 are obsolete. If $SAFE is set to 2 or larger, an ArgumentError is raised. [Feature #5455]

C API updates

• rb_define_class_id_under() now raises a TypeError exception when the class is already defined but its superclass does not match the given superclass, as well as definitions in ruby level.

• rb_timespec_now() is added to fetch current datetime as struct timespec.

  Feature #11558

• rb_time_timespec_new() is added to create a time object with epoch, nanosecond, and UTC/localtime/time offset arguments. [Feature #11558]

• rb_autoload() deprecated, use rb_funcall() instead. [Feature #11664]

• rb_compile_error_with_enc(), rb_compile_error(), and rb_compile_bug() deprecated. these functions are exposed but only for internal use. external libraries should not use them.

Supported platform changes

• OS/2 is no longer supported

• BeOS is no longer supported

• Borland-C is no longer supported

• Haiku now stable and best effort

Implementation improvements

• Optimize Proc#call to eliminate method frame construction.

  Feature #11569

• Reconsidering method entry data structure.

  Bug #11278

• Introducing new table data structure for ID keys tables used by method table and so on. New table structure is simple and fast than st_table. [Feature #11420]

• Machine code level tuning for object allocation and method calling code. r52099, r52254

• RubyVM::InstructionSequence is extended for future improvement.

  Feature #11788

• Case dispatch is now optimized for all special constant literals including nil, true, and false. Previously, only literal strings, symbols, integers and floats compiled to optimized case dispatch.

  Feature #11769

• Instance variables on non-pure Ruby classes (T_DATA, T_FILE, etc..) is less expensive to store than before. [Feature #11170]

• All accesses to members of big Struct objects are performed in constant-time. Previously, Struct elements beyond the first 10 10 elements used a linear scan. [Feature #10585]

• The Set class got several speed up.

  Misc #10754], [r52591

• Socket and I/O-related improvements

  • Calling overhead of most of new keyword-using I/O methods in

    Feature #11229

    is reduced by avoiding the inefficient C API

    to parse keywords. [Feature #11339]

  • The standard library is updated to use the improved exception-free non-blocking I/O from [Feature #11229]. This has the additional benefit of quieter $DEBUG output in addition to reducing expensive exceptions. [Feature #11044]

  • (Linux-only) waiting on a single FD anywhere in the stdlib no longer uses select(2), making it immune to slowdowns with high-numbered FDs.

    Feature #11081

    Feature #11377

• CGI.escapeHTML is optimized with C extention. github.com/ruby/ruby/pull/1164