October 2025 - ruby-core - ml.ruby-lang.org

[ruby-core:123560] [Ruby Bug#21651] replacing a string with one backslash with two backslashes
by tdrive (Stanislav Boldaev) 28 Oct '25

28 Oct '25

Issue #21651 has been reported by tdrive (Stanislav Boldaev). ---------------------------------------- Bug #21651: replacing a string with one backslash with two backslashes https://bugs.ruby-lang.org/issues/21651 * Author: tdrive (Stanislav Boldaev) * Status: Open * ruby -v: 3.4.4 * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ruby 2.7.8p225 (2023-03-30 revision 1f4d455848) [x86_64-linux] ruby 3.4.4 (2025-05-14 revision a38531fd3f) +PRISM [x86_64-linux] ``` irb(main):002> "\\".gsub("\\", "\\\\") => "\\" irb(main):003> "\\".gsub("\\", "\\ \\") => "\\ \\" ``` The replacement is happening, as you can see from the version with the space, but why is the result so strange without the space? Similar code works fine in JS: ``` "\\".replace("\\", "\\\\") > '\\\\' ``` How to replace one backslash with two backslashes? -- https://bugs.ruby-lang.org/

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[ruby-core:123558] [Ruby Bug#21650] Performance regression: `Rational#floor(ndigits)` extremely slow for huge ndigits in Ruby 3.4 (ok in 3.2)
by koilanetroc (Oleg Tolmashov) 28 Oct '25

28 Oct '25

Issue #21650 has been reported by koilanetroc (Oleg Tolmashov). ---------------------------------------- Bug #21650: Performance regression: `Rational#floor(ndigits)` extremely slow for huge ndigits in Ruby 3.4 (ok in 3.2) https://bugs.ruby-lang.org/issues/21650 * Author: koilanetroc (Oleg Tolmashov) * Status: Open * ruby -v: ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [arm64-darwin24] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ## Summary `Rational#floor(ndigits)` with a very large positive ndigits takes tens of seconds in Ruby 3.4, while it returns essentially instantly in Ruby 3.2. Reproducible on macOS and Linux. Looks like a missing fast‑path for rationals whose decimal expansion terminates. ## Steps to reproduce ```ruby require "benchmark" puts RUBY_DESCRIPTION t = Benchmark.realtime { (2 ** -3).floor(2 ** 31) } puts "elapsed: #{t.round(3)}s" ``` Also reproduces with the explicit rational form: ```ruby Benchmark.realtime { Rational(1, 8).floor(2 ** 31) } ``` ### Results on my machine Ruby 3.2.8: ``` ruby 3.2.8 (2025-03-26 revision 13f495dc2c) [arm64-darwin24] slow_math.rb:4: warning: in a**b, b may be too big elapsed: 0.0s ``` Ruby 3.4.7: ``` ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [arm64-darwin24] elapsed: 39.214s ``` ## Actual behavior On Ruby 3.4.x this call takes ~tens of seconds (e.g., ~40s on my machine), consuming CPU. Same on macOS and Linux. ## Expected behavior The method should return quickly (ideally O(1)). -- https://bugs.ruby-lang.org/

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[ruby-core:123506] [Ruby Misc#21646] Propose Luke Gruber as a Ruby committer
by jhawthorn (John Hawthorn) 28 Oct '25

28 Oct '25

Issue #21646 has been reported by jhawthorn (John Hawthorn). ---------------------------------------- Misc #21646: Propose Luke Gruber as a Ruby committer https://bugs.ruby-lang.org/issues/21646 * Author: jhawthorn (John Hawthorn) * Status: Open ---------------------------------------- I'd like to propose adding Luke Gruber (@luke-gru) as a Ruby committer. He's been contributing to CRuby since 2019 fixing a variety of bugs and being active on redmine both filing and fixing issues. For the past few years he's made a lot of improvements to help stabilize Ractors and we've been working together on this for the past several months. A small sample of his work (more from [@luke-gruber and @luke-gru on GitHub](https://github.com/search?q=repo%3Aruby%2Fruby%20is%3Apr%20author%3…) * Fixed a complex lock-ordering issue that caused Ractors to deadlock [ruby/ruby#13682](https://github.com/ruby/ruby/pull/13682) * Optimizing `Regexp#match` to avoid allocations [ruby/ruby#9398](https://github.com/ruby/ruby/pull/9398) * Fixed issues with moving objects to a Ractor [ruby/ruby#9394](https://github.com/ruby/ruby/pull/9394) [ruby/ruby#9996](https://github.com/ruby/ruby/pull/9996) * Fixed a GC+Ractor+tracing bug that crashed on CI [ruby/ruby#14596](https://github.com/ruby/ruby/pull/14596) * Fixed a bug where Mutexes locked by finished Fibers could segv [ruby/ruby#14262](https://github.com/ruby/ruby/pull/14262) * Fixed String#crypt inside Ractors [ruby/ruby#13567](https://github.com/ruby/ruby/pull/13567) It would be helpful to me and to Ruby if he had commit access to merge changes more easily. I would help with onboarding :) -- https://bugs.ruby-lang.org/

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[ruby-core:123279] [Ruby Misc#21609] Propose Stan Lo (@st0012) as a core committer
by tekknolagi (Maxwell Bernstein) 28 Oct '25

28 Oct '25

Issue #21609 has been reported by tekknolagi (Maxwell Bernstein). ---------------------------------------- Misc #21609: Propose Stan Lo (@st0012) as a core committer https://bugs.ruby-lang.org/issues/21609 * Author: tekknolagi (Maxwell Bernstein) * Status: Open ---------------------------------------- ## Proposal I'd like to propose Stan Lo (@st0012) as a committer. He's been doing excellent work on ZJIT for the past couple of months, making sure we're compatible with the test suite, analyzing benchmark data, and optimizing the generated code. Especially since he has been contributing to Ruby for years now and knows the community, I think he should be able to merge his own changes. Here is Stan's message: ## Stan Lo's message I have been contributing to Ruby and core Ruby tools since 2021\. My main contributions have been: ### ZJIT Contributions ([60+ PRs](https://github.com/ruby/ruby/pulls?q=is%3Apr+author%3Ast0012+ZJIT+is%3…) - Made ZJIT work with TracePoint ([\#14407](https://github.com/ruby/ruby/pull/14407), [\#14420](https://github.com/ruby/ruby/pull/14420)) - Built infrastructure for annotating builtin functions ([\#14078](https://github.com/ruby/ruby/pull/14078)) - Implemented invalidation for method redefinition ([\#13875](https://github.com/ruby/ruby/pull/13875)), stable constants ([\#13998](https://github.com/ruby/ruby/pull/13998)), single Ractor mode ([\#14121](https://github.com/ruby/ruby/pull/14121)) - Supported compiling instructions: `concatstrings` ([\#14154](https://github.com/ruby/ruby/pull/14154)), `opt_and`/`opt_or` ([\#13830](https://github.com/ruby/ruby/pull/13830)), `invokeblock` ([\#14496](https://github.com/ruby/ruby/pull/14496)), `opt_case_dispatch` ([\#14433](https://github.com/ruby/ruby/pull/14433)) - Expanded test infrastructure to run against all Ruby tests ([\#13950](https://github.com/ruby/ruby/pull/13950)) ### Core Ruby Tools - **IRB** \- [All-time \#1 contributor](https://github.com/ruby/irb/graphs/contributors) and maintainer since 2022 - Implemented major features across Ruby 3.2-3.4: `cd` command, `edit` command, `show_cmds`, pager support, integration with `ruby/debug`…etc. - **RDoc** \- Maintainer since 2024 - Redesigned the default theme for Ruby 3.4+ ([\#1191](https://github.com/ruby/rdoc/pull/1191), [\#1157](https://github.com/ruby/rdoc/pull/1157)) - Created docs.ruby-lang.org with new homepage ([\#12227](https://github.com/ruby/ruby/pull/12227)) and greatly improved standard library page ([\#12404](https://github.com/ruby/ruby/pull/12404)) - **Debug** \- [\#2 contributor with 400+ commits](https://github.com/ruby/debug/graphs/contributors) - IRB integration ([\#1024](https://github.com/ruby/debug/pull/1024)) - `outline` command ([\#173](https://github.com/ruby/debug/pull/173)) - Backtrace filtering ([\#138](https://github.com/ruby/debug/pull/138)) I would like to continue contributing to ZJIT, IRB, RDoc, and other parts of Ruby. Being a committer would make it easier to maintain these critical tools and contribute to ZJIT's ongoing development. -- https://bugs.ruby-lang.org/

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[ruby-core:123549] [Ruby Bug#21649] Ractors can access non-shareable object through singleton classes
by jhawthorn (John Hawthorn) 27 Oct '25

27 Oct '25

Issue #21649 has been reported by jhawthorn (John Hawthorn). ---------------------------------------- Bug #21649: Ractors can access non-shareable object through singleton classes https://bugs.ruby-lang.org/issues/21649 * Author: jhawthorn (John Hawthorn) * Status: Open * Assignee: ractor * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- If we send a non-shareable object into a Ractor, it needs to be copied. ``` ❯ ruby -W0 -e 'Ractor.new(p(Object.new)) { |o| p(o) }.join' #<Object:0x00000001240f8cf8> #<Object:0x00000001240f8870> ``` However we're able to instead smuggle it through a singleton class to unsafely get a mutable reference to the same object in both Ractors. ``` ❯ ruby -W0 -e 'Ractor.new(p(Object.new).singleton_class) { |o| p(o.attached_object) }.join' #<Object:0x0000000120768c40> #<Object:0x0000000120768c40> ``` I think we should probably make singleton classes copy the shareability of their attached object. -- https://bugs.ruby-lang.org/

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[ruby-core:123541] [Ruby Feature#15381] Let double splat call `to_h` implicitly
by sanjioh (Fabio Sangiovanni) 25 Oct '25

25 Oct '25

Issue #15381 has been updated by sanjioh (Fabio Sangiovanni). jeremyevans0 (Jeremy Evans) wrote in #note-11: > […] Maybe in Ruby 4? Bringing this up since it seems that this year’s Ruby version will be 4.0. Is this change going to be considered for inclusion in the new release? ---------------------------------------- Feature #15381: Let double splat call `to_h` implicitly https://bugs.ruby-lang.org/issues/15381#change-114919 * Author: sawa (Tsuyoshi Sawada) * Status: Open ---------------------------------------- The single splat calls `to_a` implicitly on the object (if it is not an array already) so that, for example, we have the convenience of writing conditions in an array literal: ```ruby a = [ *(:foo if some_condition), *(:bar if another_condition), ] ``` And the ampersand implicitly calls `to_proc` on the object (if it is not a proc already) so that we can substitute a block with an ampersand followed by a symbol: ```ruby some_method(&:some_method_name) ``` Unlike the single splat and ampersand, the double splat does not seem to implicitly call a corresponding method. I propose that the double splat should call `to_h` implicitly on the object if it not already a Hash so that we can, for example, write a condition in a hash literal as follows: ```ruby h = { **({a: 1} if some_condition), **({b: 2) if another_condition), } ``` There may be some other benefits of this feature that I have not noticed yet. -- https://bugs.ruby-lang.org/

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[ruby-core:122883] [Ruby Bug#21522] Accessing outer locals via eval in a Ractor returns false
by tenderlovemaking (Aaron Patterson) 24 Oct '25

24 Oct '25

Issue #21522 has been reported by tenderlovemaking (Aaron Patterson). ---------------------------------------- Bug #21522: Accessing outer locals via eval in a Ractor returns false https://bugs.ruby-lang.org/issues/21522 * Author: tenderlovemaking (Aaron Patterson) * Status: Open * Assignee: ractor * ruby -v: ruby 3.5.0dev (2025-07-28T22:17:45Z master f1acf47ca2) +PRISM [arm64-darwin24] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Normally, if you try to access a local that's been defined outside the scope of the Ractor block, it'll raise an ArgumentError. However, if you try to access the local via `eval` it will return the value `false`. ```ruby foo = Object.new begin Ractor.new { p foo }.value rescue ArgumentError end Ractor.new { p eval("foo") # => false }.value ``` I'm not sure how we fix this, since my guess is that we zero the environment when copying, but I wanted to file the issue so we can track it. -- https://bugs.ruby-lang.org/

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[ruby-core:116083] [Ruby master Feature#20163] Introduce #bit_count method on Integer
by garrison (Garrison Jensen) 24 Oct '25

24 Oct '25

Issue #20163 has been reported by garrison (Garrison Jensen). ---------------------------------------- Feature #20163: Introduce #bit_count method on Integer https://bugs.ruby-lang.org/issues/20163 * Author: garrison (Garrison Jensen) * Status: Open * Priority: Normal ---------------------------------------- This feature request is to implement a method called #bit_count on Integer that returns the number of ones in the binary representation of the absolute value of the integer. ``` n = 19 n.bit_count #=> 3 (-n).bit_count #=> 3 ``` This is often useful when you use an integer as a bitmask and want to count how many bits are set. This would be equivalent to ``` n.to_s(2).count("1") ``` However, this can be outperformed by ``` def bit_count(n) count = 0 while n > 0 n &= n - 1 # Flip the least significant 1 bit to 0 count += 1 end count end ``` I think this would be a useful addition because it would fit alongside the other bit-related methods defined on integer: `#bit_length,` `#allbits?`, `#anybits?`, `#nobits?`. Also, when working with bitmasks, a minor upgrade to performance often results in a significant improvement. Similar methods from other languages: https://docs.python.org/3/library/stdtypes.html#int.bit_count https://doc.rust-lang.org/std/primitive.i32.html#method.count_ones -- https://bugs.ruby-lang.org/

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[ruby-core:123241] [Ruby Feature#21572] Make illegal variable in alternation pattern a syntax error
by kddnewton (Kevin Newton) 23 Oct '25

23 Oct '25

Issue #21572 has been reported by kddnewton (Kevin Newton). ---------------------------------------- Feature #21572: Make illegal variable in alternation pattern a syntax error https://bugs.ruby-lang.org/issues/21572 * Author: kddnewton (Kevin Newton) * Status: Open ---------------------------------------- Currently when you have an illegal variable in an alternation pattern, you get a compile error, but no syntax error. ```ruby case foo in {a: } | Array "matched: #{a}" end ``` yields ``` $ ruby -cv test.rb ruby 3.5.0dev (2025-04-10T10:21:51Z master 756479324f) +PRISM [x86_64-linux] Syntax OK ``` but ``` $ ruby test.rb test.rb:2: illegal variable in alternative pattern (a) test.rb: compile error (SyntaxError) ``` Looking at the compiler, since illegal jumps (like break, next, etc.) are now syntax errors, the only other actual compiler errors are related to builtins. I think this should be a proper syntax error, so that editors and other tools can report on it and users can find it in development sooner. -- https://bugs.ruby-lang.org/

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[ruby-core:123319] [Ruby Feature#21615] Introduce `Array#values`
by matheusrich (Matheus Richard) 23 Oct '25

23 Oct '25

Issue #21615 has been reported by matheusrich (Matheus Richard). ---------------------------------------- Feature #21615: Introduce `Array#values` https://bugs.ruby-lang.org/issues/21615 * Author: matheusrich (Matheus Richard) * Status: Open ---------------------------------------- ## Motivation In Ruby code, it's common to accept arrays and hashes and treat them uniformly as collections of values. `Hash` exposes `#values`, but `Array` does not, which pushes developers toward `is_a?`/`respond_to?` branching. Following the **Principle of Least Surprise**, users may reasonably expect `Array#values` to exist because: * Both `Array` **and** `Hash` already implement `#values_at`. * `Hash` implements `#values` but `Array` does not. ### Example Today: ```ruby def normalize_records(input) items = input.respond_to?(:values) ? input.values : input items.each do |item| do_stuff_with_item(item) end end ``` With `Array#values`: ```ruby def normalize_records(input) input.values.each do |item| do_stuff_with_item(item) end end ``` ## Proposal Add `Array#values`, returning `self`. Implementation could simply alias to `itself`: ```ruby class Array alias_method :values, :itself end ``` This yields a uniform interface for `Array` and `Hash` values without type checks. ### Alternatives considered * `Enumerable#values`: defaulting to `to_a`, but I found it too broad of a change. * `Array#each_value`: redundant as `Array#each` already covers iteration. Patch: https://github.com/ruby/ruby/pull/14641 -- https://bugs.ruby-lang.org/

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