# 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. [Feature #11537]

    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

- 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 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 extension. github.com/ruby/ruby/pull/1164