# -*- rdoc -*-

= NEWS for Ruby 2.2.0

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.

== Changes since the 2.1.0 release

=== Language changes

* nil/true/false
  * nil/true/false objects are frozen. [Feature #8923]

* Hash literal
  * Symbol key followed by a colon can be quoted. [Feature #4276]

* default argument
  fixed a very longstanding bug that an optional argument was not
  accessible in its default value expression.  [Bug #9593]

=== Core classes updates (outstanding ones only)

* Binding
  * New methods:
    * Binding#local_variables
    * Binding#receiver

* Dir
  * New methods:
    * Dir#fileno

* Enumerable
  * New methods:
    * Enumerable#slice_after
    * Enumerable#slice_when
  * Extended methods:
    * min, min_by, max and max_by supports optional argument to return
      multiple elements.

* Float
  * New methods:
    * Float#next_float
    * Float#prev_float

* File
  * New methods:
    * File.birthtime
    * File#birthtime

* File::Stat
  * New methods:
    * File::Stat#birthtime

* GC
  * GC.latest_gc_info returns :state to represent current GC status.
  * Improvements
    * Introduce incremental marking for major GC. [Feature #10137]

* IO
  * Improvements
    * IO#read_nonblock and IO#write_nonblock for pipes on Windows are supported.

* Kernel
  * New methods:
    * Kernel#itself
  * Improvements
    * Kernel#throw raises UncaughtThrowError, subclass of ArgumentError when
      there is no corresponding catch block, instead of ArgumentError.

* Process
  * Extended method:
    * Process execution methods such as Process.spawn opens the file in write
      mode for redirect from [:out, :err].

* String
  * New methods:
    * String#unicode_normalize
    * String#unicode_normalize!
    * String#unicode_normalized?

* Symbol
  * Improvements
    * Most symbols which are returned by String#to_sym and
      String#intern are GC-able.

* Method
  * New methods:
    * Method#curry([ arity ]) returns a curried Proc.
    * Method#super_method returns a Method of superclass, which would be called
      when super is used.

=== Core classes compatibility issues (excluding feature bug fixes)

* Enumerable
  * Enumerable#slice_before's state management deprecated.
  * Enumerable#chunk's state management deprecated.

* GC
  * incompatible changes:
    * Rename GC.stat entries. [Feature #9924]
      See https://docs.google.com/spreadsheets/d/11Ua4uBr6o0k-nORrZLEIIUkHJ9JRzRR0NyZfrhEEnc8/edit?usp=sharing

* Hash
  * incompatible changes:
    * Change overriding policy for duplicated key. [Bug #10315]
      { **hash1, **hash2 } contains values of hash2 for duplicated keys.

* IO
  * incompatible changes:
    * When flushing file IO with IO#flush, you cannot assume that the metadata
      of the file is updated immediately.  On some platforms (especially
      Windows), it is delayed until the filesystem load is decreased.
      Use IO#fsync if you want to guarantee updating metadata.

* Math
  * incompatible changes:
    * Math.log now raises Math::DomainError instead of returning NaN if the
      base is less than 0, and returns NaN instead of -infinity if both of
      two arguments are 0.
    * Math.atan2 now returns values like as expected by C99 if both two
      arguments are infinity.

* Proc
  * incompatible changes:
    * ArgumentError is no longer raised when lambda Proc is passed as a
      block, and the number of yielded arguments does not match the formal
      arguments of the lambda, if just an array is yielded and its length
      matches.

* Process
  * Process execution methods such as Process.spawn opens the file in write
    mode for redirect from [:out, :err].
    Before Ruby 2.2, it was opened in read mode.

=== Stdlib updates (outstanding ones only)

* Continuation
  * callcc is obsolete. use Fiber instead.

* Digest

  * Digest() should now be thread-safe.  If you have a problem with
    regard to on-demand loading under a multi-threaded environment,
    preload "digest/*" modules on boot or use this method instead of
    directly referencing Digest::*.
  * Digest::HMAC has been removed just as previously noticed.

* DL
  * DL has been removed from stdlib. Please use Fiddle instead!

* Etc
  * New methods:
    * Etc.uname
    * Etc.sysconf
    * Etc.confstr
    * IO#pathconf
    * Etc.nprocessors

* Find, Pathname
  * Extended methods:
    * find method accepts "ignore_error" keyword argument.

* Matrix
  * New methods:
    * Matrix#first_minor(row, column) returns the submatrix obtained
      by deleting the specified row and column.
    * Matrix#cofactor(row, column) returns the (row, column) cofactor
      which is obtained by multiplying the first minor by (-1)**(row + column).
    * Matrix#adjugate returns the adjugate of the matrix.
    * hstack and vstack are new instance and class methods to stack matrices
      horizontally and vertically.
    * Matrix#laplace_expansion(row_or_column: num) returns the laplace_expansion
      along the +num+ -th row or column.
    * Vector.basis(size:, index:) returns the specified basis vector.
    * Unary - and + added for Vector and Matrix.
    * Vector#cross_product generalized to arbitrary dimensions.
    * Vector#dot and #cross are aliases for #inner_product and #cross_product.
    * Vector#angle_with returns the angle with its argument
    * New instance and class method independent? to test linear independence.

* Pathname
  * Pathname#/ is aliased to Pathname#+.
  * New methods:
    * Pathname#birthtime

* Rake
  * Updated to Rake 10.4.0.  For full release notes see:

    http://docs.seattlerb.org/rake/History_rdoc.html#label-10.4.0

* RubyGems
  * Updated to RubyGems 2.4.2.  For full release notes see:

    http://docs.seattlerb.org/rubygems/History_txt.html#label-2.4.2+%2F+2014-10-01

* TSort
  * TSort.tsort_each, TSort.each_strongly_connected_component and
    TSort.each_strongly_connected_component_from returns an enumerator if
    no block given.

* XMLRPC
  * Added new parser class named LibXMLStreamParser.

=== Stdlib compatibility issues (excluding feature bug fixes)

* lib/mathn.rb
  * Show deprecated warning [Feature #10169]

* ext/date/lib/date/format.rb
  * Removed because it's empty file.

* Digest
  * Digest::HMAC has finally ceased to exist.  Use OpenSSL::HMAC or an external gem instead.

* time.rb
  * Time.parse, Time.strptime, Time.rfc2822, Time.xmlschema may produce
    fixed-offset Time objects.
    It is happen when usual localtime doesn't preserve the offset from UTC.
  * Time.httpdate produces always UTC Time object.
  * Time.strptime raises ArgumentError when no date information.

* lib/rational.rb
  * Removed because it is deprecated from 2009.

* lib/complex.rb
  * Removed because it is deprecated from 2009.

* lib/prettyprint.rb
  * Removed PrettyPrint#first?

* lib/minitest/*.rb
  * Removed because it conflicts to minitest 5. [Feature #9711]

* lib/test/**/*.rb
  * Removed because it conflicts to minitest 5, and it was just an wrapper
    of minitest 4. [Feature #9711]

* lib/uri
  * support RFC 3986. [Feature #2542]

* GServer
  * GServer is extracted to gserver gem. It's unmaintain code.

* Logger
  * Logger::Application is extracted to logger-application gem. It's unmaintain code.

* ObjectSpace (after requiring "objspace")
  * ObjectSpace.memsize_of(obj) returns a size includes sizeof(RVALUE). [Bug #8984]

* Prime
  * incompatible changes:
    * Prime.prime? now returns false for negative numbers. This method
      should not be used to know the number is composite or not. [Bug #7395]

* Psych
  * Removed Psych::EngineManager [Bug #8344]

=== Built-in global variables compatibility issues

=== C API updates

* Deprecated APIs removed.  [Feature #9502]

  Check_SafeStr -> SafeStringValue
  rb_check_safe_str -> SafeStringValue
  rb_quad_pack -> rb_integer_pack
  rb_quad_unpack -> rb_integer_unpack
  rb_read_check : access struct FILE internal. no replacement.
  rb_struct_iv_get : internal function. no replacement.
  struct rb_blocking_region_buffer : internal type. no replacement.
  rb_thread_blocking_region_begin -> rb_thread_call_without_gvl family
  rb_thread_blocking_region_end -> rb_thread_call_without_gvl family
  TRAP_BEG -> rb_thread_call_without_gvl family
  TRAP_END -> rb_thread_call_without_gvl family
  rb_thread_select -> rb_thread_fd_select
  struct rb_exec_arg : internal type. no replacement.
  rb_exec : internal function. no replacement.
  rb_exec_arg_addopt : internal function. no replacement.
  rb_exec_arg_fixup : internal function. no replacement.
  rb_exec_arg_init : internal function. no replacement.
  rb_exec_err : internal function. no replacement.
  rb_fork : internal function. no replacement.
  rb_fork_err : internal function. no replacement.
  rb_proc_exec_n : internal function. no replacement.
  rb_run_exec_options : internal function. no replacement.
  rb_run_exec_options_err : internal function. no replacement.
  rb_thread_blocking_region -> rb_thread_call_without_gvl family
  rb_thread_polling -> rb_thread_wait_for
  rb_big2str0 : internal function. no replacement.
  rb_big2ulong_pack -> rb_integer_pack
  rb_gc_set_params : internal function. no replacement.
  rb_io_mode_flags -> rb_io_modestr_fmode
  rb_io_modenum_flags -> rb_io_oflags_fmode

* struct RBignum is hidden.  [Feature #6083]
  Use rb_integer_pack and rb_integer_unpack instead.

* struct RRational is hidden.  [Feature #9513]
  Use rb_rational_num and rb_rational_den instead.

* rb_big_new and rb_big_resize takes a size_t instead of long.

* rb_num2long returns a long instead of SIGNED_VALUE.

* rb_num2ulong returns an unsigned long instead of VALUE.

* st hash table uses power-of-two sizes for speed [Feature #9425].
  Lookups are 10-25% faster if using appropriate hash functions.
  However, weaknesses in hash distribution can no longer be masked
  by prime number-sized tables, so extensions may need to tweak
  hash functions to ensure good distribution.

* rb_sym2str() added. This is almost same as `rb_id2str(SYM2ID(sym))`
  but not pinning a dynamic symbol.

* rb_str_cat_cstr() added. This is the same as `rb_str_cat2()`.

* `rb_str_substr()` and `rb_str_subseq()` will share middle of a string,
  but not only the end of a string, in the future.  Therefore, result
  strings may not be NUL-terminated, `StringValueCStr()` is needed
  calling to obtain a NUL-terminated C string.

* rb_tracepoint_new() supports new internal events accessible only from C:
  * RUBY_INTERNAL_EVENT_GC_ENTER
  * RUBY_INTERNAL_EVENT_GC_EXIT
    r47528

* rb_hash_delete() now does not call the block given to the current method.

* rb_extract_keywords() and rb_get_kwargs() exported.  See README.EXT
  for details.

=== Build system updates

* jemalloc is optionally supported via `./configure --with-jemalloc`
  jemalloc may be suitable when system malloc is slow or prone
  to fragmentation.  [Feature #9113]

=== Implementation changes

* GC
    * Most symbols which are returned by String#to_sym and
      String#intern are GC-able [Feature #9634]
    * Introduce incremental marking for major GC. [Feature #10137]
    * Enable lazy sweep on GC caused by malloc().

* VM
    * Use frozen string literals for Hash#[] and Hash#[]=
    * Fast keyword arguments passing [Feature #10440]
    * Allow to receive huge splatted array by a rest argument [Feature #10440]

* Process
    * Process creation methods, such as spawn(), uses vfork() system call.
      vfork() is faster than fork() when the parent process uses huge memory.
