NEWS for Ruby 3.4.0¶ ↑

This document is a list of user-visible feature changes since the 3.3.0 release, except for bug fixes.

Note that each entry is kept to a minimum, see links for details.

Language changes¶ ↑

• String literals in files without a frozen_string_literal comment now behave as if they were frozen. If they are mutated a deprecation warning is emitted. These warnings can be enabled with -W:deprecated or by setting Warning[:deprecated] = true. To disable this change, you can run Ruby with the --disable-frozen-string-literal command line argument. [Feature #20205]

• it is added to reference a block parameter. [Feature #18980]

• Keyword splatting nil when calling methods is now supported. **nil is treated similarly to **{}, passing no keywords, and not calling any conversion methods. [Bug #20064]

• Block passing is no longer allowed in index. [Bug #19918]

• Keyword arguments are no longer allowed in index. [Bug #20218]

Core classes updates¶ ↑

Note: We’re only listing outstanding class updates.

• Exception

• Exception#set_backtrace now accepts arrays of Thread::Backtrace::Location. Kernel#raise, Thread#raise and Fiber#raise also accept this new format. [Feature #13557]

• Range

• Range#size now raises TypeError if the range is not iterable. [Misc #18984]

Stdlib updates¶ ↑

The following default gems are updated.

• RubyGems 3.6.0.dev

• bundler 2.6.0.dev

• erb 4.0.4

• fiddle 1.1.3

• io-console 0.7.2

• irb 1.12.0

• json 2.7.2

• net-http 0.4.1

• optparse 0.5.0

• prism 0.25.0

• rdoc 6.6.3.1

• reline 0.5.2

• resolv 0.4.0

• stringio 3.1.1

• strscan 3.1.1

The following bundled gems are updated.

• minitest 5.22.3

• rake 13.2.1

• test-unit 3.6.2

• net-ftp 0.3.4

• net-imap 0.4.10

• net-smtp 0.5.0

• rbs 3.4.4

• typeprof 0.21.11

• debug 1.9.2

The following bundled gems are promoted from default gems.

• mutex_m 0.2.0

• getoptlong 0.2.1

• base64 0.2.0

• bigdecimal 3.1.7

• observer 0.1.2

• abbrev 0.1.2

• resolv-replace 0.1.1

• rinda 0.2.0

• drb 2.2.1

• nkf 0.2.0

• syslog 0.1.2

• csv 3.3.0

See GitHub releases like GitHub Releases of Logger or changelog for details of the default gems or bundled gems.

Supported platforms¶ ↑

Compatibility issues¶ ↑

• Error messages and backtrace displays have been changed.

• Use a single quote instead of a backtick as a opening quote. Feature #16495

• Display a class name before a method name (only when the class has a permanent name). Feature #19117

• Kernel#caller, Thread::Backtrace::Location‘s methods, etc. are also changed accordingly. “ Old: test.rb:1:infoo’: undefined method time' for an instance of Integer from test.rb:2:in<main>‘

New: test.rb:1:in ‘Object#foo’: undefined method ‘time’ for an instance of Integer from test.rb:2:in ‘<main>’ “‘

Stdlib compatibility issues¶ ↑

C API updates¶ ↑

• rb_newobj and rb_newobj_of (and corresponding macros RB_NEWOBJ, RB_NEWOBJ_OF, NEWOBJ, NEWOBJ_OF) have been removed. [Feature #20265]

• Removed deprecated function rb_gc_force_recycle. [Feature #18290]

Implementation improvements¶ ↑

• Array#each is rewritten in Ruby for better performance [Feature #20182].

JIT¶ ↑

Miscellaneous changes¶ ↑

• Passing a block to a method which doesn't use the passed block will show a warning on verbose mode (-w). [Feature #15554]

• Redefining some core methods that are specially optimized by the interpeter and JIT like String.freeze or Integer#+ now emits a performance class warning (-W:performance or Warning[:performance] = true). [[Feature #20429]]