February 2026 - ruby-core - ml.ruby-lang.org

[ruby-core:121642] [Ruby Bug#21266] YJIT GC safety crash with proc objects as block argument
by alanwu (Alan Wu) 22 Mar '26

22 Mar '26

Issue #21266 has been reported by alanwu (Alan Wu). ---------------------------------------- Bug #21266: YJIT GC safety crash with proc objects as block argument https://bugs.ruby-lang.org/issues/21266 * Author: alanwu (Alan Wu) * Status: Open * Assignee: yjit * Backport: 3.2: DONTNEED, 3.3: REQUIRED, 3.4: REQUIRED ---------------------------------------- ```ruby # Run with --yjit-call-threshold=1 def foo(args) = bar(*args, &proc { _1 }) def bar(_, _, _, _, *rest) = yield rest GC.stress = true foo([1,2,3,4]) foo([1,2,3,4]) ``` The proc in these calls get collected on the yield to the GC to allocate the rest parameter arary. ``` ../vm_core.h:1668: Assertion Failed: vm_block_handler_type:rb_obj_is_proc(block_handler) ``` Or in release builds: ``` ../test.rb:1: [BUG] Segmentation fault at 0x0000000000000020 ruby 3.3.6 (2024-11-05 revision 75015d4c1f) +YJIT [arm64-darwin24] -- C level backtrace information ------------------------------------------- /Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_vm_bugreport+0xb4c) [0x104595590] /Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_bug_for_fatal_signal+0x100) [0x1043d6120] /Users/alan/.rubies/ruby-3.3.6/bin/ruby(sig_do_nothing+0x0) [0x1044fc4b0] /usr/lib/system/libsystem_platform.dylib(_sigtramp+0x38) [0x187572de4] /Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_vm_invokeblock+0x144) [0x10456b004] ``` -- https://bugs.ruby-lang.org/

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[ruby-core:124808] [Ruby Misc#21877] DevMeeting-2026-03-17
by mame (Yusuke Endoh) 17 Mar '26

17 Mar '26

Issue #21877 has been reported by mame (Yusuke Endoh). ---------------------------------------- Misc #21877: DevMeeting-2026-03-17 https://bugs.ruby-lang.org/issues/21877 * Author: mame (Yusuke Endoh) * Status: Open ---------------------------------------- # The next dev meeting **Date: 2026/03/17 13:00-17:00** (JST) Log: *TBD* - Dev meeting *IS NOT* a decision-making place. All decisions should be done at the bug tracker. - Dev meeting is a place we can ask Matz, nobu, nurse and other developers directly. - Matz is a very busy person. Take this opportunity to ask him. If you can not attend, other attendees can ask instead of you (if attendees can understand your issue). - We will write a record of the discussion in the file or to each ticket in English. - All activities are best-effort (keep in mind that most of us are volunteer developers). - The date, time and place of the meeting are scheduled according to when/where we can reserve Matz's time. - *DO NOT* discuss then on this ticket, please. # Call for agenda items If you have a ticket that you want matz and committers to discuss, please post it into this ticket in the following format: ``` * [Ticket ref] Ticket title (your name) * Comment (A summary of the ticket, why you put this ticket here, what point should be discussed, etc.) ``` Example: ``` * [Feature #14609] `Kernel#p` without args shows the receiver (ko1) * I feel this feature is very useful and some people say :+1: so let discuss this feature. ``` - It is recommended to add a comment by 2026/03/14. We hold a preparatory meeting to create an agenda a few days before the dev-meeting. - The format is strict. We'll use [this script to automatically create an markdown-style agenda](https://gist.github.com/mame/b0390509ce1491b43610b9ebb665eb86). We may ignore a comment that does not follow the format. - Your comment is mandatory. We cannot read all discussion of the ticket in a limited time. We appreciate it if you could write a short summary and update from a previous discussion. -- https://bugs.ruby-lang.org/

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[ruby-core:124660] [Ruby Feature#21858] `Kernel#Hash` considers `to_h` too
by ccmywish (Aoran Zeng) 17 Mar '26

17 Mar '26

Issue #21858 has been reported by ccmywish (Aoran Zeng). ---------------------------------------- Feature #21858: `Kernel#Hash` considers `to_h` too https://bugs.ruby-lang.org/issues/21858 * Author: ccmywish (Aoran Zeng) * Status: Open ---------------------------------------- 1. `Kernel#Integer` uses `to_int` first and `to_i` second 2. `Kernel#Array` uses `to_ary` first and `to_a` second 3. `Kernel#Hash` only uses `to_hash` I don't quite understand why there is a need for differential treatment here. I admit that maybe the only benefit of considering `to_h` secondly is that it enables multiple APIs to maintain consistency. -- https://bugs.ruby-lang.org/

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[ruby-core:124857] [Ruby Bug#21921] Hash inconsistent ==, >=, <= behavior
by cohen (Cohen Carlisle) 17 Mar '26

17 Mar '26

Issue #21921 has been reported by cohen (Cohen Carlisle). ---------------------------------------- Bug #21921: Hash inconsistent ==, >=, <= behavior https://bugs.ruby-lang.org/issues/21921 * Author: cohen (Cohen Carlisle) * Status: Open * ruby -v: ruby 4.0.1 (2026-01-13 revision e04267a14b) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- Hash seems to have very inconsistent behavior for `==`, `>=`, and `<=`. Given that below h1 == h2 is `false` and that they have the same number of keys, I would expect `<=` and `>=` to also be `false`. However, surprisingly `h1 <= h2` and `h2 >= h1` are `true`, while all other permutations are `false`. ``` h1 = {}.compare_by_identity.tap { _1["one"] = 1 } # => {"one" => 1} h2 = {"one" => 1} # => {"one" => 1} h1 == h2 # => false h2 == h1 # => false h1 >= h2 # => false h1 <= h2 # => true h2 >= h1 # => true h2 <= h1 # => false ``` -- https://bugs.ruby-lang.org/

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[ruby-core:122847] [Ruby Feature#21520] Feature Proposal: Enumerator::Lazy#peek
by nuzair46 (Nuzair Rasheed) 17 Mar '26

17 Mar '26

Issue #21520 has been reported by nuzair46 (Nuzair Rasheed). ---------------------------------------- Feature #21520: Feature Proposal: Enumerator::Lazy#peek https://bugs.ruby-lang.org/issues/21520 * Author: nuzair46 (Nuzair Rasheed) * Status: Open ---------------------------------------- # Abstract Add a #peek method to Enumerator::Lazy that allows observing each element in a lazy enumeration pipeline without modifying or consuming the stream. # Background Ruby provides Enumerator::Lazy for efficient lazy stream processing. However, unlike languages such as Java, it lacks a clean way to inspect intermediate elements during lazy evaluation. Currently, developers must misuse .map for side effects, example: ```rb (1..).lazy.map { |x| puts x; x }.select(&:even?).first(3) ``` This is semantically incorrect and confusing, since .map implies transformation, not observation. # Proposal Introduce Enumerator::Lazy#peek, which yields each item to a block and returns the item unmodified, similar to Object#tap, but in a lazy stream: ```rb (1..).lazy .peek { |x| puts "saw: #{x}" } .select(&:even?) .first(3) ``` This would be equivalent to: ```rb lazy.map { |x| block.call(x); x } ``` but with improved semantic clarity. # Use cases • Debugging lazy enumerators without breaking the chain • Logging or instrumentation in pipelines • Educational / demo use for showing lazy evaluation step-by-step • Cleaner replacement for map { puts x; x } hacks Example: ```rb data = (1..).lazy .peek { |x| puts "got #{x}" } .select(&:even?) .first(5) ``` result: ```rb got 1 got 2 got 3 got 4 got 5 ``` And return [2, 4, 6, 8, 10] # Discussion #peek is a minimal, non-breaking addition that improves clarity and idiomatic usage of Enumerator::Lazy. It avoids abusing .map for observation and is familiar to developers from other languages. #peek is also not needed for other enumerators where .tap or .each can do the job. It mirrors Java’s .stream().peek(...) and makes Ruby’s lazy enumeration more expressive and readable. # See also • [Java Stream.peek](https://docs.oracle.com/javase/8/docs/api/java/util/stream/Str… I would be glad to work on this and make a PR. Thank you. -- https://bugs.ruby-lang.org/

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[ruby-core:124892] [Ruby Feature#21929] Add configure script options for instrumenting Rust builds
by jprokop (Jarek Prokop) 17 Mar '26

17 Mar '26

Issue #21929 has been reported by jprokop (Jarek Prokop). ---------------------------------------- Feature #21929: Add configure script options for instrumenting Rust builds https://bugs.ruby-lang.org/issues/21929 * Author: jprokop (Jarek Prokop) * Status: Open ---------------------------------------- Ruby at this moment optionally includes Rust bits. Right now this touches mostly YJIT and ZJIT. Rust is a compiled language with various compile flags at various stages and approaches. My ask is to provide a way to instrument compilation similarly as with C at the moment so that packagers and distributions can be fully and easily compliant with their guidelines on compilation flags. Currently, for production build of Ruby, `rustc` tool is used, which is instrumented differently from `cargo` in debug builds. In my PR motivated by the described goal: https://github.com/ruby/ruby/pull/15695 I have focused on providing `rustc` with our distribution flags, during the PR it was mentioned that there are flags related to security https://github.com/ruby/ruby/pull/15695#discussion_r2663651764 that should be present even when providing distribution flags. This is not too different from C, as there are also security flags, such as configure script enabling the arm64's BTI and PAC when possible. `rustc` of version 1.92, at the time of the PR uses the last mention of a flag. Ideally `rustc` would know `RUSTFLAGS`, but as far as I can tell, the enviroment variable only affects `cargo`. In Fedora the current guidance recommends using `%build_rustflags` https://docs.fedoraproject.org/en-US/packaging-guidelines/Rust/#_compiler_f… which expands to `-Copt-level=3 -Cdebuginfo=2 -Ccodegen-units=1 -Cstrip=none -Cforce-frame-pointers=yes --cap-lints=warn` The best result is each part of Rust in Ruby would receive the flags defined during `configure` time. In cases where complication flags should conflict, in Fedora distribution flags take precedence: https://docs.fedoraproject.org/en-US/packaging-guidelines/Rust/#_building_w… -- https://bugs.ruby-lang.org/

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[ruby-core:124797] [Ruby Feature#21875] Handling of trailing commas in lambda parameters
by Earlopain (Earlopain _) 17 Mar '26

17 Mar '26

Issue #21875 has been reported by Earlopain (Earlopain _). ---------------------------------------- Feature #21875: Handling of trailing commas in lambda parameters https://bugs.ruby-lang.org/issues/21875 * Author: Earlopain (Earlopain _) * Status: Open ---------------------------------------- https://bugs.ruby-lang.org/issues/19107 was accepted, which is about trailing commands in method definitions. lambdas were not explicitly mentioned but I wanted to confirm how they should behave with a trailing comma. Or if a trailing comma should even be accepted for them. It's not clear to me since lambdas sometimes behave like blocks and sometimes more like methods. `->(...) {}` for example is syntax invalid (same as in blocks) but they do check their arity with blocks don't do. If a trailing comma is accepted it can either * be implicit splat like in `foo do |bar,|; end` or `foo do |bar|; end`. It would also mean that the trailing comma is only allowed after a positional argument. * Just be ignored and be accepted in most places like for method definitions. The first option would be rather useless in regards to https://bugs.ruby-lang.org/issues/19107 when you just want to add the comma for cleaner diffs. But I guess for lambdas this happens very rarely anyways. -- https://bugs.ruby-lang.org/

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[ruby-core:124677] [Ruby Feature#21861] C API: expose `ruby_xfree_sized`, `ruby_xrealloc_sized`, etc
by byroot (Jean Boussier) 17 Mar '26

17 Mar '26

Issue #21861 has been reported by byroot (Jean Boussier). ---------------------------------------- Feature #21861: C API: expose `ruby_xfree_sized`, `ruby_xrealloc_sized`, etc https://bugs.ruby-lang.org/issues/21861 * Author: byroot (Jean Boussier) * Status: Open ---------------------------------------- ### Context For the longest time now, Ruby had internal API such as `ruby_sized_xfree`, `ruby_sized_xrealloc` and `ruby_sized_xrealloc2`. These are identical to their non-sized counterpart, expect they accept the original size of the buffer being free or reallocated. This information is then fed to the garbage collector to improve heuristics as to when GC should run (`malloc_increase_bytes` and `oldmalloc_increase_bytes`). When the old buffer size isn't provided, Ruby tries to obtain it via `malloc_usable_size`, which isn't available on all platform, but also isn't quite correct as it's generally over reporting. It also happen to be quite slow on some allocators, such as `mallocng`, the allocator used by `muslc` hence by alpine linux. ### C23 `free_sized` The C23 standard added the `free_sized(void *ptr, size_t oldsize)` API, and it's now available in `glibc 2.43`, other popular allocators like `jemalloc` and `tcmalloc` also have it since a few years. Original spec: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2699.htm Interestingly the standard doesn't include a `realloc_sized` API, I'm unsure why. For most allocators, providing the size to `free_sized` allow to skip some step and provide a speedup. I've read some 30% claims, but I haven't benchmarked myself. One thing to note is that according to the standard, passing the wrong size is undefined behavior: > If ptr is the result obtained from a call to `malloc(size)`, `realloc(old_ptr, size)`, or `calloc(nmemb, memb_size)`, where `nmemb * memb_size` is equal to `size`, this function behaves equivalently to `free(ptr)`. Otherwise, the result is undefined. Recently I refactored most internal calls to `xfree` inside Ruby itself to use `ruby_sized_xfree` instead, and would like to have it use `free_sized` when available. Also when `RUBY_DEBUG` is defined, `xmalloc` does register the original allocated size, and enforce that the size provided to `ruby_sized_xfree` does match. This allowed to uncover several small bugs, notably in `string.c` where we'd sometime end up with an incorrect `capacity` attribute after an encoding change. ### Benefits Aside from the performance gains on some allocators, and the gains from having more accurate GC statistics, I believe these sized interfaces help ensure correctness of the code. Except for a few exceptions, most code dealing with a buffer must know its size to avoid going out of bound, so providing it to `ruby_xfree_sized` allows to assert the size was correctly tracked in debug builds. I also believe ASAN or UBSAN are likely to also enforce this soon (if they don't already), so it could help catch more bugs early. ### Proposal I would like to expose these sized APIs to C extensions, so that they can benefit from it as well: - `void ruby_xfree_sized(void *ptr, size_t oldsize)` - `void *ruby_xrealloc_sized(void *ptr, size_t newsize, size_t oldsize)` - `void *ruby_xrealloc2_sized(void *ptr, size_t n, size_t size, size_t old_n)` I also think I would be useful to expose the corresponding macros: - `RB_REALLOC_SIZED_N` - `RB_SIZED_FREE` (shorthand to free a simple pointer: `ruby_xfree_sized(ptr, sizeof(*ptr))`). - `RB_SIZED_FREE_N` -- https://bugs.ruby-lang.org/

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[ruby-core:124877] [Ruby Misc#21924] Register a Maven artifact for JVM-related libraries
by headius (Charles Nutter) 17 Mar '26

17 Mar '26

Issue #21924 has been reported by headius (Charles Nutter). ---------------------------------------- Misc #21924: Register a Maven artifact for JVM-related libraries https://bugs.ruby-lang.org/issues/21924 * Author: headius (Charles Nutter) * Status: Open ---------------------------------------- For the Prism project, I am working toward having published artifacts for JVM users (like JRuby or TruffleRuby). Publishing these packages will make it much easier for us to support Prism in JRuby, both as our interal Ruby parser and as an installable gem. We do not copy sources into our repository, and *must* be able to point a release artifact that can be tracked through supply chain tooling etc. In order to publish artifacts, we need to register the `org.ruby-lang` namespace with Sonatype, maintainers of Maven Central (the primary source of JVM-based software packages). The process is detailed here: https://central.sonatype.org/register/namespace/ The simple description of the process follows: 1. Register an account on Sonatype. I already have one for JRuby and other JVM projects. 2. Register the namespace. I have posted an initial request for the `org.ruby-lang` namespace. 3. Verify the namespace. This requires DNS help as described on the above page and in the screenshot below. 4. Publish artifacts to the namespace. The first artifact would be named something like `prism-ruby-parser`, so its "coordinates" would be `org.ruby-lang:prism-ruby-parser:0.0.1`. I need: * Someone who can update the DNS entry to include the key needed by Sonatype for verification. * A list of users who should potentially have push rights for this namespace. I don't expect anyone but JRuby committers and possibly TruffleRuby committers will be using this namespace. For the moment I will be publishing the artifacts I need under the `org.jruby` namespace, but because there's very little JRuby-specific logic in the core Prism JVM wrapper library, I would prefer to publish it under the `org.ruby-lang` domain. -- https://bugs.ruby-lang.org/

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[ruby-core:120819] [Ruby master Bug#21097] `x = a rescue b in c` and `def f = a rescue b in c` parsed differently between parse.y and prism
by tompng (tomoya ishida) 16 Mar '26

16 Mar '26

Issue #21097 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #21097: `x = a rescue b in c` and `def f = a rescue b in c` parsed differently between parse.y and prism https://bugs.ruby-lang.org/issues/21097 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 3.5.0dev (2025-01-27T08:19:32Z master c3c7300b89) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ~~~ruby x = a rescue b in c (x = (a rescue b)) in c # parse.y, prism(ruby 3.4) x = (a rescue (b in c)) # prism(ruby 3.5) ~~~ ~~~ruby def f = a rescue b in c #=> true(parse.y), :f(prism) (def f = (a rescue b)) in c # parse.y def f = (a rescue (b in c)) # prism ~~~ There is no difference between prism and parse.y parsing these codes ~~~ruby a rescue b in c # a rescue (b in c) x = a rescue b # x = (a rescue b) x = b in c # (x = b) in c def f = a rescue b # def f = (a rescue b) def f = b in c # (def f = a) in b ~~~ -- https://bugs.ruby-lang.org/

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