NEWS for Ruby 4.1.0

This document is a list of user-visible feature changes since the 4.0.0 release, except for bug fixes.

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

Language changes

Core classes updates

Note: We're only listing outstanding class updates.

• Array

  • Array#pack accepts a new format R and r for unpacking unsigned and signed LEB128 encoded integers. [Feature #21785]

• ENV

  • ENV.fetch_values is added. It returns an array of values for the given names, raising KeyError for missing names unless a block is given. [[Feature #21781]]

• Kernel

  • Kernel#autoload_relative and Module#autoload_relative are added. These methods work like autoload, but resolve the file path relative to the file where the method is called, similar to require_relative. This makes it easier to autoload constants from files in the same directory without hardcoding absolute paths or manipulating $LOAD_PATH. [Feature #15330]

• MatchData

  • MatchData#integer_at is added. It converts the matched substring to integer and return the result. [Feature #21932]

• Regexp

  • All instances of Regexp are now frozen, not just literals. Subclasses of Regexp are not frozen for compatibility. [Feature #8948]

• Set

  • A deprecated behavior, Set#to_set, Range#to_set, and Enumerable#to_set accepting arguments, was removed. [Feature #21390]

Stdlib updates

The following bundled gems are added.

We only list stdlib changes that are notable feature changes.

Other changes are listed in the following sections. We also listed release history from the previous bundled version that is Ruby 3.4.0 if it has GitHub releases.

The following bundled gems are promoted from default gems.

• tsort 0.2.0
• win32-registry 0.1.2

The following default gem is added.

The following default gems are updated.

• RubyGems 4.1.0.dev
• bundler 4.1.0.dev
• json 2.19.3
  • 2.18.0 to v2.18.1, v2.19.0, v2.19.1, v2.19.2, v2.19.3
• openssl 4.0.1
  • 4.0.0 to v4.0.1
• prism 1.9.0
  • 1.8.1 to v1.9.0
• resolv 0.7.1
  • 0.7.0 to v0.7.1
• stringio 3.2.1.dev
• strscan 3.1.7.dev
  • 3.1.6 to v3.1.7
• syntax_suggest 2.0.3
• timeout 0.6.1
  • 0.6.0 to v0.6.1
• zlib 3.2.3
  • 3.2.2 to v3.2.3

The following bundled gems are updated.

• minitest 6.0.3
• test-unit 3.7.7
  • 3.7.5 to 3.7.6, 3.7.7
• net-imap 0.6.3
  • 0.6.2 to v0.6.3
• rbs 4.0.2
  • 3.10.0 to v3.10.1, v3.10.2, v3.10.3, v3.10.4, v4.0.0.dev.5, v4.0.0, v4.0.2
• mutex_m 0.3.0
• bigdecimal 4.1.1
  • 4.0.1 to v4.1.0, v4.1.1
• resolv-replace 0.2.0
  • 0.1.1 to v0.2.0
• syslog 0.4.0
  • 0.3.0 to v0.4.0
• repl_type_completor 0.1.15
  • 0.1.12 to v0.1.13, v0.1.14, v0.1.15
• pstore 0.2.1
  • 0.2.0 to v0.2.1
• rdoc 7.2.0
  • 7.0.3 to v7.1.0, v7.2.0
• win32ole 1.9.3
  • 1.9.2 to v1.9.3
• irb 1.17.0
  • 1.16.0 to v1.17.0

RubyGems and Bundler

Ruby 4.0 bundled RubyGems and Bundler version 4. see the following links for details.

Supported platforms

Compatibility issues

Stdlib compatibility issues

C API updates

Embedded TypedData

• The RUBY_TYPED_EMBEDDABLE flag is now public and documented and can be used by C extensions. It allows allocating C structs directly into Ruby object slots, which reduces pointer chasing, and in some case memory usage. See the C extension documentation for details. [Feature #21853]

• Added new C23 inspired allocator functions, that takes the previous memory size. This allow the Ruby GC to better keep track of memory usage, improving its heuristics. It also improves the performance of system allocators that support C23 free_sized.

However, it is important to note that passing an incorrect size to these function is undefined behavior and may result in crashes or memory leaks.

• ruby_xfree_sized(void *ptr, size_t size)
• ruby_xrealloc_sized(void *ptr, size_t newsiz, size_t oldsiz)
• ruby_xrealloc2_sized(void *ptr, size_t newelems, size_t newsiz, size_t oldelems)

[Feature #21861]

Implementation improvements

Ractor

A lot of work has gone into making Ractors more stable, performant, and usable. These improvements bring Ractor implementation closer to leaving experimental status.

JIT