# NEWS for Ruby 2.0.0¶ ↑

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 1.9.3 release¶ ↑

### Language changes¶ ↑

- Added keyword arguments.

- Added %i and %I for symbol list creation (similar to %w and %W).

- Default source encoding is changed to UTF-8. (was US-ASCII)

- No warning for unused variables starting with ‘_’

### Core classes updates (outstanding ones only)¶ ↑

- `ARGF`

  - added method:

    - added ARGF#codepoints and `ARGF#each_codepoint`, like the corresponding methods for `IO`.

- `Array`

  - added method:

    - added `Array#bsearch` for binary search.

  - incompatible changes:

    - random parameter of `Array#shuffle!` and `Array#sample` now will be called with one argument, maximum value.

    - when given `Range` arguments, `Array#values_at` now returns nil for each value that is out-of-range.

- `Enumerable`

  - added method:

    - added `Enumerable#lazy` method for lazy enumeration.

- `Enumerator`

  - added method:

    - added `Enumerator#size` for lazy size evaluation.

  - extended method:

    - `Enumerator.new` accept an argument for lazy size evaluation.

  - new class `Enumerator::Lazy` for lazy enumeration

- `ENV`

  - aliased method:

    - `ENV.to_h` is a new alias for `ENV.to_hash`

- `Fiber`

  - incompatible changes:

    - `Fiber#resume` cannot resume a fiber which invokes “Fiber#transfer”.

- `File`

  - extended method:

    - `File.fnmatch?` now expands braces in the pattern if File::FNM_EXTGLOB option is given.

- `GC`

  - improvements:

    - introduced the bitmap marking which suppresses to copy a memory page with Copy-on-Write.

    - introduced the non-recursive marking which avoids unexpected stack overflow.

- `GC::Profiler`

  - added method:

    - added `GC::Profiler.raw_data` which returns raw profile data for `GC`.

- `Hash`

  - added method:

    - added `Hash#to_h` as explicit conversion method, like `Array#to_a`.

  - extended method:

    - `Hash#default_proc=` can be passed nil to clear the default proc.

- `IO`

  - deprecated methods:

    - IO#lines, bytes, chars and codepoints are deprecated.

- `Kernel`

  - added method:

    - added `Kernel#Hash` conversion method like Array() or Float().

    - added Kernel#__dir__ which returns the absolute path of the directory of the file from which this method is called.

    - added `Kernel#caller_locations` which returns an array of frame information objects.

  - extended method:

    - `Kernel#warn` accepts multiple args in like puts.

    - `Kernel#caller` accepts second optional argument ‘n’ which specify required caller size.

    - Kernel#to_enum and enum_for accept a block for lazy size evaluation.

  - incompatible changes:

    - system() and exec() close non-standard file descriptors (The default of :close_others option is changed to true by default.)

    - respond_to? against a protected method now returns false unless the second argument is true.

    - __callee__ has returned to the original behavior, and now returns the called name but not the original name in an aliased method.

    - Kernel#inspect does not call to_s anymore (it used to call redefined to_s).

- `LoadError`

  - added method:

    - added `LoadError#path` method to return the file name that could not be loaded.

- `Module`

  - added method:

    - added `Module#prepend` which is similar to `Module#include`, however a method in the prepended module overrides the corresponding method in the prepending module.

    - added `Module.prepended` and `Module.prepend_features`, similar to included and append_features.

    - added `Module#refine`, which extends a class or module locally. [experimental]

  - extended method:

    - `Module#define_method` accepts a `UnboundMethod` from a `Module`.

    - `Module#const_get` accepts a qualified constant string, e.g. Object.const_get(“Foo::Bar::Baz”)

- Mutex

  - added method:

    - added Mutex#owned? which returns the mutex is held by current thread or not. [experimental]

  - incompatible changes:

    - Mutex#lock, Mutex#unlock, Mutex#try_lock, Mutex#synchronize and Mutex#sleep are no longer allowed to be used from trap handler and raise a `ThreadError` in such case.

    - Mutex#sleep may spurious wakeup. Check after wakeup.

- `NilClass`

  - added method:

    - added nil.to_h which returns {}

- `ObjectSpace::WeakMap`

  - new low level class to hold weak references to objects.

- `Proc`

  - incompatible change:

    - removed `Proc#==` and eql? so two procs are == only when they are the same object.

- `Process`

  - added method:

    - added getsid for getting session id (unix only).

- `Range`

  - added method:

    - added `Range#size` for lazy size evaluation.

    - added `Range#bsearch` for binary search.

- `RubyVM` (MRI specific)

  - added `RubyVM::InstructionSequence.of` to get the instruction sequence from a method or a block.

  - added `RubyVM::InstructionSequence#path`, absolute_path, label, base_label and first_lineno to retrieve information from where the instruction sequence was defined.

  - added Environment variables to specify stack usage:

    - RUBY_THREAD_VM_STACK_SIZE: vm stack size used at thread creation. default: 128KB (32bit CPU) or 256KB (64bit CPU).

    - RUBY_THREAD_MACHINE_STACK_SIZE: machine stack size used at thread creation. default: 512KB or 1024KB.

    - RUBY_FIBER_VM_STACK_SIZE: vm stack size used at fiber creation. default: 64KB or 128KB.

    - RUBY_FIBER_MACHINE_STACK_SIZE: machine stack size used at fiber creation. default: 256KB or 512KB.

    These variables are checked only at launched time.

  - added constant DEFAULT_PARAMS to get above default parameters.

- `Signal`

  - added method:

    - added `Signal.signame` which returns signal name

  - incompatible changes:

    - `Signal.trap` raises `ArgumentError` when :SEGV, :BUS, :ILL, :FPE, :VTALRM are specified.

- `String`

  - added method:

    - added `String#b` returning a copied string whose encoding is ASCII-8BIT.

  - change return value:

    - `String#lines` now returns an array instead of an enumerator.

    - `String#chars` now returns an array instead of an enumerator.

    - `String#codepoints` now returns an array instead of an enumerator.

    - `String#bytes` now returns an array instead of an enumerator.

- `Struct`

  - added method:

    - added `Struct#to_h` returning values with keys corresponding to the instance variable names.

- `Thread`

  - added method:

    - added `Thread#thread_variable_get` for getting thread local variables (these are different than `Fiber` local variables).

    - added `Thread#thread_variable_set` for setting thread local variables.

    - added `Thread#thread_variables` for getting a list of the thread local variable keys.

    - added `Thread#thread_variable?` for testing to see if a particular thread variable has been set.

    - added `Thread.handle_interrupt` as well as instance and singleton methods pending_interrupt? for asynchronous handling of exceptions

    - added `Thread#backtrace_locations` which returns similar information of `Kernel#caller_locations`.

  - new class `Thread::Backtrace::Location` to hold backtrace location information. These are returned by `Thread#backtrace_locations` and `Kernel#caller_locations`.

  - incompatible changes:

    - `Thread#join` and `Thread#value` now raises a `ThreadError` if target thread is the current or main thread.

- `Time`

  - change return value:

    - `Time#to_s` now returns US-ASCII encoding instead of BINARY.

- `TracePoint`

  - new class. This class is replacement of set_trace_func. Easy to use and efficient implementation.

- toplevel

  - added method:

    - added main.define_method which defines a global function.

    - added main.using, which imports refinements into the current file or eval string. [experimental]

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

- `Array#values_at`

  See above.

- `String#lines`

- `String#chars`

- `String#codepoints`

- `String#bytes`

  These methods no longer return an `Enumerator`, although passing a block is still supported for backwards compatibility.

  Code like str.lines.with_index(1) { |line, lineno| … } no longer works because str.lines returns an array. Replace lines with each_line in such cases.

- IO#lines

- IO#chars

- IO#codepoints

- IO#bytes

- ARGF#lines

- ARGF#chars

- ARGF#bytes

- StringIO#lines

- StringIO#chars

- StringIO#codepoints

- StringIO#bytes

- Zlib::GzipReader#lines

- Zlib::GzipReader#bytes

  These methods are deprecated in favor of each_line, each_byte, each_char and each_codepoint.

- `Proc#==`

- `Proc#eql?`

  These methods were removed. Two procs are == only when they are the same object.

- Fixnum

- Bignum

- `Float`

  Fixnums, Bignums and Floats are frozen.

- `Signal.trap`

  See above.

- Merge Onigmo. github.com/k-takata/Onigmo

- The :close_others option is true by default for system() and exec(). Also, the close-on-exec flag is set by default for all new file descriptors. This means file descriptors doesn’t inherit to spawned process unless explicitly requested such as system(…, fd=>fd).

- Kernel#respond_to? against a protected method now returns false unless the second argument is true.

- Kernel#respond_to_missing?

- Kernel#initialize_clone

- Kernel#initialize_dup

  These methods are now private.

- `Thread#join`, `Thread#value`

  See above.

- Mutex#lock, Mutex#unlock, Mutex#try_lock, Mutex#synchronize and Mutex#sleep

  See above.

### Stdlib updates (outstanding ones only)¶ ↑

- cgi

  - Add HTML5 tag maker.

  - `CGI#header` has been renamed to `CGI#http_header` and aliased to `CGI#header`.

  - When HTML5 tagmaker called, overwrite `CGI#header`, `CGI#header` function is to create a <header> element.

- `CSV`

  - Removed CSV::dump and CSV::load to protect users from dangerous serialization vulnerability

- iconv

  - Iconv has been removed. Use `String#encode` instead.

- io/console

  - new methods:

    - added `IO#cooked` which sets the terminal to cooked mode within the given block.

    - added `IO#cooked!` which sets the terminal to cooked.

  - extended method:

    - `IO#raw`, `IO#raw!`, and `IO#getch` accept keyword arguments, :min and :time.

- io/wait

  - new features:

    - added `IO#wait_writable` method.

    - added `IO#wait_readable` method as alias of `IO#wait`.

- json

  - updated to 1.7.7.

- net/http

  - new features:

    - Proxies are now automatically detected from the http_proxy environment variable. See `Net::HTTP::new` for details.

    - gzip and deflate compression are now requested for all requests by default. See `Net::HTTP` for details.

    - SSL sessions are now reused across connections for a single instance. This speeds up connection by using a previously negotiated session.

    - Requests may be created from a `URI` which sets the request_uri and host header of the request (but does not change the host connected to).

    - Responses contain the `URI` requested which allows easier implementation of redirect following.

  - new methods:

    - `Net::HTTP#local_host`

    - `Net::HTTP#local_host=`

    - `Net::HTTP#local_port`

    - `Net::HTTP#local_port=`

  - extended method:

    - `Net::HTTP#connect` uses local_host and local_port if specified.

- net/imap

  - new methods:

    - Net::IMAP.default_port

    - Net::IMAP.default_imap_port

    - Net::IMAP.default_tls_port

    - Net::IMAP.default_ssl_port

    - Net::IMAP.default_imaps_port

- objspace

  - new method:

    - `ObjectSpace.reachable_objects_from(obj)`

- openssl

  - Consistently raise an error when trying to encode nil values. All instances of `OpenSSL::ASN1::Primitive` now raise `TypeError` when calling to_der on an instance whose value is nil. All instances of `OpenSSL::ASN1::Constructive` raise `NoMethodError` in the same case. Constructing such values is still permitted.

  - TLS 1.1 & 1.2 support by setting OpenSSL::SSL::SSLContext#ssl_version to :TLSv1_2, :TLSv1_2_server, :TLSv1_2_client or :TLSv1_1, :TLSv1_1_server :TLSv1_1_client. The version being effectively used can be queried with OpenSSL::SSL#ssl_version. Furthermore, it is also possible to blacklist the new TLS versions with OpenSSL::SSL::OP_NO_TLSv1_1 and OpenSSL::SSL::OP_NO_TLSv1_2.

  - Added `OpenSSL::SSL::SSLContext#renegotiation_cb`. A user-defined callback may be set which gets called whenever a new handshake is negotiated. This also allows to programmatically decline (client) renegotiation attempts.

  - Support for “0/n” splitting of records as BEAST mitigation via OpenSSL::SSL::OP_DONT_INSERT_EMPTY_FRAGMENTS.

  - The default options for `OpenSSL::SSL::SSLContext` have changed to OpenSSL::SSL::OP_ALL & ~OpenSSL::SSL::OP_DONT_INSERT_EMPTY_FRAGMENTS instead of OpenSSL::SSL::OP_ALL only. This enables the countermeasure for the BEAST attack by default.

  - `OpenSSL` requires passwords for decrypting PEM-encoded files to be at least four characters long. This led to awkward situations where an export with a password with fewer than four characters was possible, but accessing the file afterwards failed. `OpenSSL::PKey::RSA`, `OpenSSL::PKey::DSA` and `OpenSSL::PKey::EC` therefore now enforce the same check when exporting a private key to PEM with a password - it has to be at least four characters long.

  - SSL/TLS support for the Next Protocol Negotiation extension. Supported with `OpenSSL` 1.0.1 and higher.

  - OpenSSL::OPENSSL_FIPS allows client applications to detect whether `OpenSSL` is FIPS-enabled. `OpenSSL.fips_mode=` allows turning on and off FIPS mode manually in order to adapt to situations where FIPS mode would be an explicit requirement.

  - Authenticated Encryption with Associated Data (AEAD) is supported via Cipher#auth_data= and Cipher#auth_tag/Cipher#auth_tag=. Currently (`OpenSSL` 1.0.1c), only GCM mode is supported.

- ostruct

  - new methods:

    - `OpenStruct#[]`, []=

    - `OpenStruct#each_pair`

    - `OpenStruct#eql?`

    - `OpenStruct#hash`

    - `OpenStruct#to_h` converts the struct to a hash.

  - extended method:

    - `OpenStruct.new` also accepts an `OpenStruct` / `Struct`.

- pathname

  - extended method:

    - `Pathname#find` returns an enumerator if no block is given.

- rake

  - rake has been updated to version 0.9.5.

    This version is backwards-compatible with previous rake versions and contains many bug fixes.

    See rake.rubyforge.org/doc/release_notes/rake-0_9_5_rdoc.html for a list of changes in rake 0.9.3, 0.9.4 and 0.9.5.

- `RDoc`

  - `RDoc` has been updated to version 4.0

    This version is largely backwards-compatible with previous rdoc versions. The most notable change is an update to the ri data format (ri data must be regenerated for gems shared across rdoc versions). Further API changes are internal and won’t affect most users.

    Notable changes include:

    - Page support for ri. Try ‘ri ruby:` for a list of pages in ruby or `ri ruby:syntax/literals` for the syntax documentation for literals.

      This also works for gems such as ‘ri rspec:README` for the rspec gem’s README file.

    - Markdown support. See ri `RDoc::Markdown` for details.

    See github.com/rdoc/rdoc/blob/master/History.rdoc for a full list of changes in rdoc 4.0.

- resolv

  - new methods:

    - `Resolv::DNS#timeouts=`

    - Resolv::DNS::Config#timeouts=

- rexml

  - REXML::Document#write supports `Hash` arguments.

  - REXML::Document#write supports new :encoding option. It changes XML document encoding. Without :encoding option, encoding in XML declaration is used for XML document encoding.

- RubyGems

  - Updated to 2.0.0

    RubyGems 2.0.0 features the following improvements:

    - Improved support for default gems shipping with ruby 2.0.0+

    - A gem can have arbitrary metadata through `Gem::Specification#metadata`

    - ‘gem search` now defaults to –remote and is anchored like gem list.

    - Added –document to replace –rdoc and –ri. Use –no-document to disable documentation, –document=rdoc to only generate rdoc.

    - Only ri-format documentation is generated by default.

    - ‘gem server` uses `RDoc::Servlet` from `RDoc` 4.0 to generate HTML documentation.

    For an expanded list of updates and bug fixes see: github.com/rubygems/rubygems/blob/master/History.txt

- shellwords

  - `Shellwords#shellescape` now stringifies the given object using to_s.

  - `Shellwords#shelljoin` accepts non-string objects in the given array, each of which is stringified using to_s.

- stringio

  - deprecated methods:

    - StringIO#lines, bytes, chars and codepoints are deprecated.

- syslog

  - Added `Syslog::Logger` which provides a `Logger` API atop `Syslog`.

  - Syslog::Priority, `Syslog::Level`, `Syslog::Option` and `Syslog::Macros` are introduced for easy detection of available constants on a running system.

- tmpdir

  - incompatible changes:

    - `Dir.mktmpdir` uses `FileUtils.remove_entry` instead of `FileUtils.remove_entry_secure`. This means that applications should not change the permission of the created temporary directory to make writable from other users.

- yaml

  - Syck has been removed. `YAML` now completely depends on libyaml being installed.

  - libyaml is now bundled with ruby, for cases where the library is not installed locally.

- zlib

  - Added streaming support for `Zlib::Inflate` and `Zlib::Deflate`. This allows processing of a stream without the use of large amounts of memory.

  - Added support for the new deflate strategies Zlib::RLE and Zlib::FIXED.

  - `Zlib` streams are now processed without the GVL. This allows gzip, zlib and deflate streams to be processed in parallel.

  - deprecated methods:

    - Zlib::GzipReader#lines and bytes are deprecated.

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

- `OpenStruct` new methods can conflict with custom attributes named “each_pair”, “eql?”, “hash” or “to_h”.

- `Dir.mktmpdir` in lib/tmpdir.rb

  See above.

### C API updates¶ ↑

- NUM2SHORT() and NUM2USHORT() added. They are similar to NUM2INT, but short.

- rb_newobj_of() and NEWOBJ_OF() added. They create a new object of a given class.