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 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.