NEWS-2.1.0 - Documentation for Ruby 4.0
Description: NEWS-2.1.0: NEWS for Ruby 2. This document is a list of user visible feature changes made between releases except for bug fixes.
Keywords: ruby,documentation,NEWS-2.1.0

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# NEWS for Ruby 2.1.0

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 2.0.0 release

### Language changes

- Now the default values of keyword arguments can be omitted. Those “required keyword arguments” need giving explicitly at the call time.

- Added suffixes for integer and float literals: ‘r’, ‘i’, and ‘ri’.

  - “42r” and “3.14r” are evaluated as Rational(42, 1) and 3.14.rationalize, respectively. But exponential form with ‘r’ suffix like “6.022e+23r” is not accepted because it is misleading.

  - “42i” and “3.14i” are evaluated as Complex(0, 42) and Complex(0, 3.14), respectively.

  - “42ri” and “3.14ri” are evaluated as Complex(0, 42r) and Complex(0, 3.14r), respectively.

- def-expr now returns the symbol of its name instead of nil.

### Core classes updates (outstanding ones only)

- `Array`

  - New methods

    - `Array#to_h` converts an array of key-value pairs into a `Hash`.

- `Binding`

  - New methods

    - `Binding#local_variable_get(symbol)`

    - `Binding#local_variable_set(symbol, obj)`

    - `Binding#local_variable_defined?(symbol)`

- `Enumerable`

  - New methods

    - `Enumerable#to_h` converts a list of key-value pairs into a `Hash`.

- `Exception`

  - New methods

    - `Exception#cause` provides the previous exception which has been caught at where raising the new exception.

- `GC`

  - improvements:

    - introduced the generational `GC` a.k.a RGenGC.

  - added environment variables:

    - RUBY_GC_HEAP_INIT_SLOTS

    - RUBY_GC_HEAP_FREE_SLOTS

    - RUBY_GC_HEAP_GROWTH_FACTOR

    - RUBY_GC_HEAP_GROWTH_MAX_SLOTS

    - RUBY_GC_MALLOC_LIMIT_MAX

    - RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR

    - RUBY_GC_OLDMALLOC_LIMIT

    - RUBY_GC_OLDMALLOC_LIMIT_MAX

    - RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR

  - obsoleted environment variables:

    - RUBY_FREE_MIN (Use RUBY_GC_HEAP_FREE_SLOTS instead)

    - RUBY_HEAP_MIN_SLOTS (Use RUBY_GC_HEAP_INIT_SLOTS instead)

- `Integer`

  - New methods

    - Fixnum#bit_length

    - Bignum#bit_length

  - Bignum performance improvement

    - Use GMP if available. GMP is used only for several operations: multiplication, division, radix conversion, GCD

- `IO`

  - extended methods:

    - `IO#seek` supports SEEK_DATA and SEEK_HOLE as whence.

    - `IO#seek` accepts symbols (:CUR, :END, :SET, :DATA, :HOLE) for 2nd argument.

    - `IO#read_nonblock` accepts optional ‘exception: false` to return symbols

    - `IO#write_nonblock` accepts optional ‘exception: false` to return symbols

- `Kernel`

  - New methods:

    - Kernel#singleton_method

- Module

  - New methods:

    - `Module#using`, which activates refinements of the specified module only in the current class or module definition.

    - `Module#singleton_class?` returns true if the receiver is a singleton class or false if it is an ordinary class or module.

  - extended methods:

    - `Module#refine` is no longer experimental.

    - `Module#include` and `Module#prepend` are now public methods.

- Mutex

  - misc

    - Mutex#owned? is no longer experimental.

- `Numeric`

  - extended methods:

    - `Numeric#step` allows the limit argument to be omitted, in which case an infinite sequence of numbers is generated. Keyword arguments ‘to` and `by` are introduced for ease of use. `by` can be 0, in which case the same value will be generated indefinitely.

- Process

  - New methods:

    - alternative methods to $0/$0=:

      - `Process.argv0()` returns the original value of $0.

      - `Process.setproctitle()` sets the process title without affecting $0.

    - `Process.clock_gettime`

    - `Process.clock_getres`

- `String`

  - “literal”.freeze is now optimized to return the same object

  - New methods:

    - `String#scrub` and `String#scrub!` verify and fix invalid byte sequence. If you want to use this function with older Ruby, consider to use string-scrub.gem.

- `Symbol`

  - All symbols are now frozen.

- pack/unpack (Array/String)

  - Q! and q! directives for long long type if platform has the type.

- toplevel

  - extended methods:

    - main.using is no longer experimental. The method activates refinements in the ancestors of the argument module to support refinement inheritance by `Module#include`.

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

- `Hash`

  - incompatible changes:

    - `Hash#reject` will return plain `Hash` object in the future versions, that is the original object’s subclass, instance variables, default value, and taintedness will be no longer copied, so now warnings are emitted when called with such `Hash`.

- `IO`

  - incompatible changes:

    - open ignore internal encoding if external encoding is ASCII-8BIT.

- `Kernel#eval`, Kernel#instance_eval, and `Module#module_eval`.

  - Copies the scope information of the original environment, which means that private, protected, public, and module_function without arguments do not affect the environment outside the eval string. For example, ‘class Foo; eval “private”; def foo; end; end’ doesn’t make Foo#foo private.

- Kernel#untrusted?, untrust, and trust

  - These methods are deprecated and their behavior is the same as tainted?, taint, and untaint, respectively. If $VERBOSE is true, they show warnings.

- `Module#ancestors`

  - The ancestors of a singleton class now include singleton classes, in particular itself.

- `Module#define_method` and `Object#define_singleton_method`

  - Now they return the symbols of the defined methods, not the methods/procs themselves.

- `Numeric#quo`

  - Raises `TypeError` instead of `ArgumentError` if the receiver doesn’t have to_r method.

- `Proc`

  - Returning from lambda proc now always exits from the `Proc`, not from the method where the lambda is created. Returning from non-lambda proc exits from the method, same as the former behavior.

`String`

    * If invalid: :replace is specified for String#encode, replace
      invalid byte sequence even if the destination encoding equals to
      the source encoding.

### Stdlib updates (outstanding ones only)

- CGI::Util

  - All class methods modulized.

- `Digest`

  - extended methods:

    - `Digest::Class.file` takes optional arguments for its constructor

- Matrix

  - Added Vector#cross_product.

- Net::SMTP

  - Added Net::SMTP#rset to implement the RSET command

- objspace

  - new method:

    - `ObjectSpace.trace_object_allocations`

    - `ObjectSpace.trace_object_allocations_start`

    - `ObjectSpace.trace_object_allocations_stop`

    - `ObjectSpace.trace_object_allocations_clear`

    - `ObjectSpace.allocation_sourcefile`

    - `ObjectSpace.allocation_sourceline`

    - `ObjectSpace.allocation_class_path`

    - `ObjectSpace.allocation_method_id`

    - `ObjectSpace.allocation_generation`

    - `ObjectSpace.reachable_objects_from_root`

    - `ObjectSpace.dump`

    - `ObjectSpace.dump_all`

- `OpenSSL::BN`

  - extended methods:

    - `OpenSSL::BN.new` allows Fixnum/Bignum argument.

- open-uri

  - Support multiple fields with same field name (like Set-Cookie).

- `Pathname`

  - New methods:

    - `Pathname#write`

    - `Pathname#binwrite`

- rake

  - Updated to 10.1.0. Major changes include removal of the class namespace, Rake::DSL to hold the rake DSL methods and removal of support for legacy rake features.

    For a complete list of changes since rake 0.9.6 see:

    rake.rubyforge.org/doc/release_notes/rake-10_1_0_rdoc.html

    rake.rubyforge.org/doc/release_notes/rake-10_0_3_rdoc.html

- `RbConfig`

  - New constants:

    - RbConfig::SIZEOF is added to provide the size of C types.

- RDoc

  - Updated to 4.1.0. Major enhancements include a modified default template

  - and accessibility enhancements.

    For a list of minor enhancements and bug fixes see: github.com/rdoc/rdoc/blob/v4.1.0.preview.1/History.rdoc

- `Resolv`

  - New methods:

    - Resolv::DNS.fetch_resource

  - One-shot multicast DNS support

  - Support LOC resources

- REXML::Parsers::SAX2Parser

  - Fixes wrong number of arguments of entitydecl event. Document of the event says “an array of the entity declaration” but implementation passes two or more arguments. It is an implementation bug but it breaks backward compatibility.

- REXML::Parsers::StreamParser

  - Supports “entity” event.

- REXML::Text

  - REXML::Text#<< supports method chain like ‘text << “XXX” << “YYY”’.

  - REXML::Text#<< supports not “raw” mode.

- Rinda::RingServer, Rinda::RingFinger

  - Rinda now supports multicast sockets. See Rinda::RingServer and Rinda::RingFinger for details.

- RubyGems

  - Updated to 2.2.0. Notable new features include:

    - Gemfile or gem.deps.rb support including Gem.file.lock (experimental)

    - Improved, iterative resolver (compared to RubyGems 2.1 and earlier)

    - Support for a sharing a GEM_HOME across ruby platforms and versions

    For a complete list of enhancements and bug fixes see: github.com/rubygems/rubygems/tree/master/History.txt

- Set

  - New methods:

    - `Set#intersect?`

    - `Set#disjoint?`

- `Socket`

  - New methods:

    - `Socket.getifaddrs`

- `StringScanner`

  - extended methods:

    - `StringScanner#[]` supports named captures.

- Syslog::Logger

  - Added facility.

- `Tempfile`

  - New methods:

    - `Tempfile.create`

- `Timeout`

  - The exception to terminate the given block can no longer be rescued inside the block, by default, unless the exception class is given explicitly.

- `TSort`

  - New methods:

    - `TSort.tsort`

    - `TSort.tsort_each`

    - `TSort.strongly_connected_components`

    - `TSort.each_strongly_connected_component`

    - `TSort.each_strongly_connected_component_from`

- WEBrick

  - The body of a response may now be a `StringIO` or other IO-like that responds to readpartial and read.

- XMLRPC::Client

  - New methods:

    - XMLRPC::Client#http. It returns `Net::HTTP` for the client. Normally, it is not needed. It is useful when you want to change minor HTTP client options. You can change major HTTP client options by XMLRPC::Client methods. You should use XMLRPC::Client methods for changing major HTTP client options instead of XMLRPC::Client#http.

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

- Set

  - incompatible changes:

    - `Set#to_set` now returns self instead of generating a copy.

- `URI`

  - incompatible changes:

    - `URI.decode_www_form` follows current WHATWG URL Standard. It gets encoding argument to specify the character encoding. It now allows loose percent encoded strings, but denies ;-separator.

    - `URI.encode_www_form` follows current WHATWG URL Standard. It gets encoding argument to convert before percent encode. UTF-16 strings aren’t converted to UTF-8 before percent encode by default.

- curses

  - Removed. curses is now available as a gem. See rubygems.org/gems/curses for details.

### Built-in global variables compatibility issues

- $SAFE

  - $SAFE=4 is obsolete. If $SAFE is set to 4 or larger, an `ArgumentError` is raised.

### C API updates

- rb_gc_set_params() is deprecated. This is only used in Ruby internal.

- rb_gc_count() added. This returns the number of times `GC` occurred.

- rb_gc_stat() added. This allows access to specific `GC.stat()` values from C without any allocation overhead.

- rb_gc_latest_gc_info() added. This allows access to `GC.latest_gc_info()`.

- rb_postponed_job_register() added. Takes a function callback which is invoked when the VM is in a consistent state, i.e. to perform work from a C signal handler.

- rb_profile_frames() added. Provides low-cost access to the current ruby stack for callstack profiling.

- rb_tracepoint_new() supports new internal events accessible only from C:

  - RUBY_INTERNAL_EVENT_NEWOBJ

  - RUBY_INTERNAL_EVENT_FREEOBJ

  - RUBY_INTERNAL_EVENT_GC_START

  - RUBY_INTERNAL_EVENT_GC_END_MARK

  - RUBY_INTERNAL_EVENT_GC_END_SWEEP

  - Note that you *can not* specify “internal events” with normal events (such as RUBY_EVENT_CALL, RUBY_EVENT_RETURN) simultaneously.