NEWS for Ruby 2.5.0

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.$FEATURE_OR_BUG_NUMBER)

Changes since the 2.4.0 release

Language changes

  • Top-level constant look-up is removed. [Feature #11547]

  • rescue/else/ensure are allowed inside do/end blocks. [Feature #12906]

  • refinements take place in string interpolations. [Feature #13812]

Core classes updates (outstanding ones only)

Stdlib updates (outstanding ones only)

  • BigDecimal

    • Update to BigDecimal 1.3.4

    • The following features are added:

      • BigDecimal::VERSION

    • The following features have been deprecated, and are planned to be removed in the version 1.4.0:

    • BigDecimal#clone and dup now do not make a new instance, but returns the receiver itself.

  • Coverage

    • Support branch coverage and method coverage measurement. [Feature #13901] Branch coverage tells you which branches are executed, and which not. Method coverage tells you which methods are invoked, and which not. By running a test suite with this new feature, you can know which branches and methods are executed by a test, and evaluate total coverage of a test suite more strictly.

      You can specify the measuring target by an option to `Coverage.start`:

      Coverage.start(lines: true, branches: true, methods: true)

      After some Ruby files are loaded, you can use `Coverage.result` to get the coverage result:

      #=> { "/path/to/file.rb"=>
      #     { :lines => [1, 2, 0, nil, ...],
      #       :branches =>
      #         { [:if, 0, 2, 1, 6, 4] =>
      #             { [:then, 1, 3, 2, 3, 8] => 0,
      #               [:else, 2, 5, 2, 5, 8] => 2
      #             }
      #         },
      #       :methods => {
      #          [Object, :foo, 1, 0, 7, 3] => 2
      #       }
      #     }
      #   }

      The result type of line coverage is not changed; it is just an array that contains numbers, which means the count that each line was executed, or `nil`s, which means that the line is not relevant.

      The result type of branch coverage is:

      { (jump base) => { (jump target) => (counter) } }

      where jump base and targets have the format

      [type, unique-id, start lineno, start column, end lineno, end column]

      For example, `[:if, 0, 2, 1, 6, 4]` reads an `if` statement that ranges from line 2 and column 1, to line 6 and column 4. `[:then, 1, 3, 2, 3, 8]` reads a `then` clause that ranges from line 3 and column 2, to line 3 and column 8. Note that lineno starts from 1, and that columnno starts from 0. So, the above example shows a branch from the `if` to the `then` was never executed, and a branch from the `if` to the `else` was executed twice.

      The result type of method coverage is:

      { (method key) => (counter) }

      where method key has the format

      [class, method-name, start lineno, start column, end lineno, end column]

      For example, `[Object, :foo, 1, 0, 7, 3]` reads `Object#foo` that ranges from line 1 and column 0, to line 7 and column 3. The above example shows this `Object#foo` was invoked twice.

      Note: To keep compatibility, passing no option to `Coverage.start` will measure only line coverage, and `Coverage.result` will return the old format:

      #=> { "/path/to/file.rb"=> [1, 2, 0, nil, ...] }
  • DRb

  • ERB

    • Add ERB#result_with_hash to render a template with local variables passed with a Hash object. [Feature #8631]

    • Default template file encoding is changed from ASCII-8BIT to UTF-8 in erb command. [Bug #14095]

    • Carriage returns are changed to be trimmed properly if trim_mode is specified and used. Duplicated newlines will be removed on Windows. [Bug #5339] [Bug #11464]

  • IPAddr

  • IRB

    • Print backtrace and error message in reverse order [Feature #8661] [experimental]

    • `binding.irb` automatically requires irb and runs [Bug #13099] [experimental]

    • `binding.irb` on its start shows source around the line where it was called

      Feature #14124
  • Matrix

  • Net::HTTP

    • supports no_proxy parameter [Feature #11195]

    • Net::HTTP#{min_version,max_version}, [Feature #9450]

    • Add more HTTP status classes

    • Net::HTTP::STATUS_CODES is added as HTTP Status Code Repository [Misc #12935]

    • Net::HTTP#{proxy_user,proxy_pass} reflect http_proxy environment variable if the system's environment variable is multiuser safe. [Bug #12921]

  • open-uri

    • method defined as an alias to open-uri's open-uri's will be deprecated in future.

  • OpenSSL

    • Updated Ruby/OpenSSL from version 2.0 to 2.1. Changes are noted in “Version 2.1.0” section in ext/openssl/

  • Pathname

  • Psych

  • RbConfig

    • RbConfig::LIMITS is added to provide the limits of C types. This is available when rbconfig/sizeof is loaded.

  • Ripper

  • RDoc

    • Update to RDoc 6.0.1.

      • Replace IRB based lexer with Ripper.

      • Support many new syntaxes of Ruby from the past few years.

      • Use “frozen_string_literal: true”. This reduces document generation time by 5%.

      • Support did_you_mean.

  • Rubygems

  • SecureRandom

    • New method:

      • SecureRandom.alphanumeric

  • Set

    • New methods:

  • StringIO

  • StringScanner

  • URI

    • Relative path operations no longer collapse consecutive slashes to a single slash. [Bug #8352]

  • WEBrick

    • Add Server Name Indication (SNI) support [Feature #13729]

    • support Proc objects as body responses [Feature #855]

    • released as a RubyGem [Feature #13173]

    • avoid unintended behavior from Kernel#open [Misc #14216]

  • Zlib

Compatibility issues (excluding feature bug fixes)

Stdlib compatibility issues (excluding feature bug fixes)

  • Gemification

    • Promote following standard libraries to default gems.

      • cmath

      • csv

      • date

      • dbm

      • etc

      • fcntl

      • fiddle

      • fileutils

      • gdbm

      • ipaddr

      • scanf

      • sdbm

      • stringio

      • strscan

      • webrick

      • zlib

  • Logger

    •“| command”) had been working to open a command unintentionally. It was prohibited, and now Logger#initialize treats a String argument only as a filename, as its specification.

      Bug #14212
  • Net::HTTP

    • Net::HTTP#start now passes :ENV to p_addr by default. [Bug #13351] To avoid this, pass nil explicitly.

  • mathn.rb

    • Removed from stdlib. [Feature #10169]

  • Rubygems

    • Removed “ubygems.rb” file from stdlib. It's needless since Ruby 1.9.

C API updates

Supported platform changes

Implementation improvements

  • (This might not be a “user visible feature change” but) Hash class's hash function is now SipHash13. [Feature #13017]

  • SecureRandom now prefers OS-provided sources than OpenSSL. [Bug #9569]

  • Mutex rewritten to be smaller and faster [Feature #13517]

  • Performance of block passing using block parameters is improved by lazy Proc allocation [Feature #14045]

  • Dynamic instrumentation for TracePoint hooks instead of using “trace” instruction to avoid overhead [Feature #14104]

  • ERB now generates code from a template which runs 2 times faster than Ruby 2.4

Miscellaneous changes

  • Print backtrace and error message in reverse order if STDERR is unchanged and a tty.

    Feature #8661
  • Print error message in bold/underlined text if STDERR is unchanged and a tty.

    Feature #14140
  • configure option –with-ext now mandates its arguments. So for instance if you run ./configure –with-ext=openssl,+ then the openssl library is guaranteed compiled, otherwise the build fails abnormally.

    Note however to always add the “,+” at the end of the argument. Otherwise nothing but openssl are built. [Feature #13302]