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

[ruby-core:123768] [Ruby Bug#21679] Segfault when ruby calls pthread_detach in rb_getnameinfo
by luke-gru (Luke Gruber) 08 Dec '25

08 Dec '25

Issue #21679 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #21679: Segfault when ruby calls pthread_detach in rb_getnameinfo https://bugs.ruby-lang.org/issues/21679 * Author: luke-gru (Luke Gruber) * Status: Open * ruby -v: 3.4.7 * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- We're seeing an issue on our servers running ruby 3.4.7 where we get a SEGV after ruby calls `pthread_detach` on a short-lived pthread that calls `getaddrinfo`. I believe it's related to this glibc bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19951. Our servers are using glibc version 2.39, which is from January 2024. This bug hasn't been fixed in glibc yet but I haven't been able to reproduce it on my Linux desktop. Regardless, there's a simple workaround for it that avoids calling `pthread_detach` on the thread. My PR is here: https://github.com/ruby/ruby/pull/15142. Thanks, Luke -- https://bugs.ruby-lang.org/

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[ruby-core:121629] [Ruby Bug#21265] Crash when proc from Symbol#to_proc called outside refinement scope
by alanwu (Alan Wu) 08 Dec '25

08 Dec '25

Issue #21265 has been reported by alanwu (Alan Wu). ---------------------------------------- Bug #21265: Crash when proc from Symbol#to_proc called outside refinement scope https://bugs.ruby-lang.org/issues/21265 * Author: alanwu (Alan Wu) * Status: Open * ruby -v: ruby 3.4.2 and trunk * Backport: 3.2: DONTNEED, 3.3: DONTNEED, 3.4: REQUIRED ---------------------------------------- ```ruby class RefinedScope using(Module.new { refine(Kernel) { def itself = 0 } }) ITSELF = :itself.to_proc end RefinedScope::ITSELF[0] ``` ``` ../vm_method.c:1371: Assertion Failed: prepare_callable_method_entry:RB_TYPE_2_P(defined_class, RUBY_T_ICLASS, RUBY_T_MODULE): defined_class: T_FALSE ``` Or SEGV without `-DRUBY_DEBUG`. -- https://bugs.ruby-lang.org/

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[ruby-core:123958] [Ruby Feature#21720] Add a native Binary Heap / Priority Queue to Ruby's Standard Library (heapify, heappush, heappop)
by rahulk501 (Rahul Kumar) 08 Dec '25

08 Dec '25

Issue #21720 has been reported by rahulk501 (Rahul Kumar). ---------------------------------------- Feature #21720: Add a native Binary Heap / Priority Queue to Ruby's Standard Library (heapify, heappush, heappop) https://bugs.ruby-lang.org/issues/21720 * Author: rahulk501 (Rahul Kumar) * Status: Open ---------------------------------------- **Title:** Add a native Binary Heap / Priority Queue to Ruby's Standard Library (`heapify`, `heappush`, `heappop`) **Problem** Ruby currently lacks a native binary heap / priority queue data structure in the standard library. Users frequently reimplement heaps manually, or install third-party gems, simply to access common operations such as: * `heapify` * `heappush` * `heappop` * efficient priority queues Meanwhile, languages like Python provide a standard `heapq` module which is widely used in algorithms, AI, scheduling, job queues, pathfinding, graph traversal, and competitive programming. Because Ruby does not include a heap implementation, developers often write ad-hoc, buggy, or inconsistent versions of a heap. This leads to fragmentation and duplication. **Proposal** Introduce a lightweight `Heap` or `BinaryHeap` class to Ruby’s standard library with the following minimal API: ```ruby heap = Heap.new(array = []) heap.push(value) heap.pop # returns smallest (min-heap) heap.peek heap.size ``` Or a module-based functional API similar to Python’s `heapq`: ```ruby Heap.heapify(array) Heap.heappush(array, value) Heap.heappop(array) ``` Both designs are simple and allow backward-compatible extension. **Why include it in the standard library?** 1. Heaps are a *fundamental data structure*—used in sorting, algorithms, scheduling, and timers. 2. Many languages include them natively (Python, C++ via STL `priority_queue`, Java, Go, Rust `BinaryHeap`). 3. Adding it reduces unnecessary reimplementations in user codebases. 4. A small heap implementation adds little maintenance burden. 5. Existing Ruby solutions (gems like `algorithms`, `priority_queue`, custom code) are not universally available and often exceed what users need. **Reference Implementation (pure Ruby, minimal example)** ```ruby module Heap def self.heapify(arr) (arr.length / 2 - 1).downto(0) { |i| sift_down(arr, i) } arr end def self.heappush(arr, value) arr << value sift_up(arr, arr.length - 1) end def self.heappop(arr) return nil if arr.empty? arr[0], arr[-1] = arr[-1], arr[0] min = arr.pop sift_down(arr, 0) min end def self.sift_up(arr, i) while i > 0 p = (i - 1) / 2 break if arr[p] <= arr[i] arr[p], arr[i] = arr[i], arr[p] i = p end end def self.sift_down(arr, i) n = arr.length loop do left = 2 * i + 1 right = 2 * i + 2 smallest = i smallest = left if left < n && arr[left] < arr[smallest] smallest = right if right < n && arr[right] < arr[smallest] break if smallest == i arr[i], arr[smallest] = arr[smallest], arr[i] i = smallest end end private_class_method :sift_up, :sift_down end ``` **Optional C implementation** If accepted, I am willing to provide a minimal C version for performance parity with other stdlib containers. **Compatibility** No breaking changes expected. Naming avoids conflict with existing libraries. **Conclusion** Adding a tiny, well-defined heap structure would strengthen Ruby’s built-in algorithmic tools, reduce duplicated code across the ecosystem, and align Ruby with other mainstream languages. -- https://bugs.ruby-lang.org/

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[ruby-core:121142] [Ruby master Misc#21154] Document or change Module#autoload?
by fxn (Xavier Noria) 07 Dec '25

07 Dec '25

Issue #21154 has been reported by fxn (Xavier Noria). ---------------------------------------- Misc #21154: Document or change Module#autoload? https://bugs.ruby-lang.org/issues/21154 * Author: fxn (Xavier Noria) * Status: Open ---------------------------------------- The documentation of `Module#autoload?` says > Returns filename to be loaded if name is registered as autoload in the namespace of mod or one of its ancestors. Cool, but in the following snippet ```ruby autoload :Foo, 'foo' autoload?(:Foo) ``` the second line could evaluate to `nil`, and this does not seem to agree. I just registered an autoload, therefore (according to the documentation) I should get "foo" back in line 2. I'd like to ask for clarification from the Ruby team: 1. Is the documentation complete? Should that second line always return "foo"? 2. If the answer is no, which is the logic missing in the docs? Thank you! -- https://bugs.ruby-lang.org/

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[ruby-core:124045] [Ruby Feature#8948] Frozen regex
by Eregon (Benoit Daloze) 07 Dec '25

07 Dec '25

Issue #8948 has been updated by Eregon (Benoit Daloze). PR to make all Regexps frozen and not just literals: https://github.com/ruby/ruby/pull/14547 Is it OK to merge it for Ruby 4.0? ---------------------------------------- Feature #8948: Frozen regex https://bugs.ruby-lang.org/issues/8948#change-115477 * Author: sawa (Tsuyoshi Sawada) * Status: Assigned * Assignee: Eregon (Benoit Daloze) ---------------------------------------- =begin I see that frozen string was accepted for Ruby 2.1, and frozen array and hash are proposed in https://bugs.ruby-lang.org/issues/8909. I feel there is even more use case for a frozen regex, i.e., a regex literal that generates a regex only once. It is frequent to have a regex within a frequently repeated portion of code, and generating the same regex each time is a waste of resource. At the moment, we can have a code like: class Foo RE1 = /pattern1/ RE2 = /pattern1/ RE3 = /pattern1/ def classify case self when RE1 then 1 when RE2 then 2 when RE3 then 3 else 4 end end end but suppose we have a frozen `Regexp` literal `//f`. Then we can write like: class Foo def classify case self when /pattern1/f then 1 when /pattern1/f then 2 when /pattern1/f then 3 else 4 end end end =end -- https://bugs.ruby-lang.org/

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[ruby-core:124040] [Ruby Feature#12928] Use socket conect_timeout in net stdlib for open_timeout
by osyoyu (Daisuke Aritomo) 05 Dec '25

05 Dec '25

Issue #12928 has been updated by osyoyu (Daisuke Aritomo). For the record: net/http now uses `TCPSocket.open(open_timeout:)` in place of `Timeout.timeout`. https://github.com/ruby/net-http/pull/224 ---------------------------------------- Feature #12928: Use socket conect_timeout in net stdlib for open_timeout https://bugs.ruby-lang.org/issues/12928#change-115471 * Author: xiewenwei (xie wenwei) * Status: Open ---------------------------------------- Current net/http and net/pop use Timeout.timeout to tigger open_timeout event. Timeout.timeout is slow. It will create and destroy a thread every time. Timeout.timeout is also dangerous. see [[http://www.mikeperham.com/2015/05/08/timeout-rubys-most-dangerous-api/]] It is more effective and safe to use socket timeout to accomplish this. Follow is the changes need to do. 1. Replace TCPSocket.open with Socket.new 2. Use socket.connect_nonblock and IO.select to connect and trigger timeout event. The pull request is here: [[https://github.com/ruby/ruby/pull/1480]] -- https://bugs.ruby-lang.org/

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[ruby-core:121791] [Ruby Bug#21298] `ObjectSpace.allocation_class_path` returns inconsistent results depending on `TracePoint` state
by mame (Yusuke Endoh) 05 Dec '25

05 Dec '25

Issue #21298 has been reported by mame (Yusuke Endoh). ---------------------------------------- Bug #21298: `ObjectSpace.allocation_class_path` returns inconsistent results depending on `TracePoint` state https://bugs.ruby-lang.org/issues/21298 * Author: mame (Yusuke Endoh) * Status: Open * Assignee: tenderlovemaking (Aaron Patterson) * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- `ObjectSpace.allocation_class_path` is an API that returns the class of `self` in the context where an object was allocated. However, due to recent optimizations in `Class#new` (#21254), the return value now changes depending on whether `TracePoint` is enabled. ```ruby require "objspace" class Foo def test obj = Object.new ObjectSpace.allocation_class_path(obj) end end ObjectSpace.trace_object_allocations_start p Foo.new.test #=> 3.4.2: "Class", master: "Foo" ``` Previously, this returned `"Class"` (from the `Class#new` call frame), but in the master branch, the result is now `"Foo"` because that frame is gone. I am ok for the incompatibility itself because I find the new behavior more intuitive and useful. However, there's an inconsistency: the optimization is disabled when `TracePoint` is enabled, causing the result to revert to the old behavior. ```ruby p Foo.new.test #=> master: "Foo" TracePoint.new {}.enable do p Foo.new.test #=> master: "Class", expected: "Foo" end ``` This makes behavior dependent on whether `TracePoint` is enabled, which can lead to confusion. @ko1 @tenderlovemaking Can we make `ObjectSpace.allocation_class_path` consistently return the class from the `.new` call context, regardless of the `TracePoint` state? --- I am facing a failure of the following test when code coverage (which uses `TracePoint`) is enabled: https://github.com/ruby/ruby/blob/e8ad728209ee22136e61054fea74096b49088b8a/… As a short-term workaround, I'm considering commenting out this test. -- https://bugs.ruby-lang.org/

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[ruby-core:112326] [Ruby master Feature#19430] Contribution wanted: DNS lookup by c-ares library
by mame (Yusuke Endoh) 05 Dec '25

05 Dec '25

Issue #19430 has been reported by mame (Yusuke Endoh). ---------------------------------------- Feature #19430: Contribution wanted: DNS lookup by c-ares library https://bugs.ruby-lang.org/issues/19430 * Author: mame (Yusuke Endoh) * Status: Open * Priority: Normal ---------------------------------------- ## Problem At the present time, Ruby uses `getaddrinfo(3)` to resolve names. Because this function is synchronous, we cannot interrupt the thread performing name resolution until the DNS server returns a response. We can see this behavior by setting blackhole.webpagetest.org (72.66.115.13) as a DNS server, which swallows all packets, and resolving any name: ``` # cat /etc/resolv.conf nameserver 72.66.115.13 # ./local/bin/ruby -rsocket -e 'Addrinfo.getaddrinfo("www.ruby-lang.org", 80)' ^C^C^C^C ``` As we see, Ctrl+C does not stop ruby. The current workaround that users can take is to do name resolution in a Ruby thread. ```ruby Thread.new { Addrinfo.getaddrinfo("www.ruby-lang.org", 80) }.value ``` The thread that calls this code is interruptible. (Note that the newly created thread itself will be stuck until the DNS lookup exceeds the time out.) ## Proposal We can solve this problem by using c-ares, which is an asynchronous name resolver, as a backend of `Addrinfo.getaddrinfo`, etc. (@sorah told me about this library, thanks!) https://c-ares.org/ I have created a PoC patch. https://github.com/mame/ruby/commit/547806146993bbc25984011d423dcc0f913b211c By applying this patch, we can interrupt `Addrinfo.getaddrinfo` by Ctrl+C. ``` # cat /etc/resolv.conf nameserver 72.66.115.13 # ./local/bin/ruby -rsocket -e 'Addrinfo.getaddrinfo("www.ruby-lang.org", 80)' ^C-e:1:in `getaddrinfo': Interrupt from -e:1:in `<main>' ``` ## Discussion ### About c-ares According to the site of c-ares, some major tools including libcurl, Wireshark, and Apache Arrow are already using c-ares. In the language interpreter, node.js seems to be using c-ares. I am honestly not sure about the compatibility of c-ares with `getaddrinfo(3)`. I guess there is no major incompatibility because I have not experienced any name resolution problem of curl. @akr (who is the author and maintainer of Ruby's socket library) suggested to check if OS-specific name resolution, e.g., WINS on Windows, NIS on Solaris, etc., is supported. He also said that it may be acceptable even if they are not supported. Whether to bundle c-ares source code with ruby would require further discussion. If this proposal is accepted, then c-ares will become a de facto essential dependency for practical use, like gmp, in my opinion. Incidentally, node.js bundles c-ares: https://github.com/nodejs/node/tree/main/deps/cares ### Alternative approaches Recent glibc provides `getaddrinfo_a(3)` which performs asynchronous name resolution. However, this function has a fatal problem of being incompatible with `fork(2)`, which is heavily used in the Ruby ecosystem. In fact, the attempt to use `getaddrinfo_a(3)` (#17134) has been revert because it fails rails tests. (#17220) Another alternative is to have a worker pthread inside Ruby that calls getaddrinfo(3). Instead of calling getaddrinfo(3) directly, `Addrinfo.getaddrinfo` would ask the worker to resolve a name and wait for a response. This method should be able to implement cancellation. (Simply put, this means reimplementation of getaddrinfo_a(3) on our own, taking into account of `fork(2).) This has the advantages: not adding dependencies on external libraries and not having compatibility issues with `getaddrinfo(3)`. However, it is considerably more difficult to implement and maintain. An internal pthread may have a non-trivial impact on the execution efficiency and memory usage. Also, we may need to implement a mechanism to dynamically change the number of workers depending on the load. It would be ideal if we could try and evaluate both approaches. But my current impression is that using c-ares is the quickest and best compromise. ## Contribution wanted I have made it up to the PoC, but don't have much time to complete this. @naruse suggested me to create a ticket asking for contributions. Is anyone interested in this? * This patch changes `rsock_getaddrinfo` to accept a timeout argument. There are several places where Qnil is passed as a timeout (where I add `// TODO` in the PoC). We need to consider what timeout we should pass. * This cares only `getaddrinfo`, but we also need to care `getnameinfo` (and something else if any). There may be some issues I'm not aware of. * I have not yet tested this PoC seriously. It would be great if we could evaluate it with some real apps. Also, it would be great to hear from someone who knows more about c-ares. -- https://bugs.ruby-lang.org/

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[ruby-core:123983] [Ruby Bug#21758] Prism fails to parse heredoc within %Q literal split by another heredoc
by tompng (tomoya ishida) 04 Dec '25

04 Dec '25

Issue #21758 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #21758: Prism fails to parse heredoc within %Q literal split by another heredoc https://bugs.ruby-lang.org/issues/21758 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 4.0.0dev (2025-12-02T16:20:43Z master c06c2203ed) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Prism fails to parse this code ~~~ruby <<A; %Q A #{<<B} B ~~~ Parse error: ~~~ a.rb:4: syntax error found (SyntaxError) 2 | A 3 | #{<<B} > 4 | B | ^ unexpected constant, expecting end-of-input ~~~ `B` at line 4 appears twice in lex result: ~~~ruby Prism.lex('<<A; %Q A #{<<B} B ').value #=> [[HEREDOC_START(1,0)-(1,3)("<<A"), 1], [HEREDOC_END(2,0)-(3,0)("A\n"), 2], [SEMICOLON(1,3)-(1,4)(";"), 1], [STRING_BEGIN(1,5)-(2,0)("%Q\n"), 1], [EMBEXPR_BEGIN(3,0)-(3,2)("\#{"), 1], [HEREDOC_START(3,2)-(3,5)("<<B"), 1], [HEREDOC_END(4,0)-(5,0)("B\n"), 2], # B\n here [EMBEXPR_END(3,5)-(3,6)("}"), 2], [STRING_END(3,6)-(4,0)("\n"), 2], [CONSTANT(4,0)-(4,1)("B"), 2], # Same B again here [NEWLINE(4,1)-(5,0)("\n"), 1], [EOF(4,1)-(5,0)("\n"), 1]] ~~~ -- https://bugs.ruby-lang.org/

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[ruby-core:123961] [Ruby Feature#21722] Expose rb_gc_mark_weak API for use in extensions
by ivoanjo (Ivo Anjo) 04 Dec '25

04 Dec '25

Issue #21722 has been reported by ivoanjo (Ivo Anjo). ---------------------------------------- Feature #21722: Expose rb_gc_mark_weak API for use in extensions https://bugs.ruby-lang.org/issues/21722 * Author: ivoanjo (Ivo Anjo) * Status: Open ---------------------------------------- In https://bugs.ruby-lang.org/issues/21710 it came up that 1. On top of [deprecating _id2ref](https://bugs.ruby-lang.org/issues/15408) on Ruby 4.0, [it's a bad idea to be using object_id from the NEWOBJ tracepoint](https://bugs.ruby-lang.org/issues/21710#note-8) 2. `rb_gc_mark_weak` which would be the alternative for an extension that needs weak reference-like behavior [is not available for extensions](https://bugs.ruby-lang.org/issues/21710#note-9) So I've opened this ticket to request exposing `rb_gc_mark_weak` so it can be used by extensions? --- The [Datadog Ruby profiler](https://github.com/datadog/dd-trace-rb) is currently using object_id and id2ref to implement its "heap profiling" -- that is, we have a NEWOBJ tracepoint, and from time to time (e.g. not for every object), we select an object, and track its lifetime by keeping its id and checking from time to time if it's still alive. We're using this approach instead of: * The FREEOBJ event => Reduced overhead, as we don't need to be called for every object (+ not needing to deal with corner cases of when FREEOBJ may not be called for an object) * WeakMap => Weakmap APIs are Ruby-level and need the GVL, and thus make it hard to use from low-level tracepoints and to avoid overhead by doing profiler work with the GVL released. For our purposes, it would be OK if this API is not "official" -- e.g. if it's one of those that gets exposed as a public symbol but not documented and no promises made for future Ruby releases. -- https://bugs.ruby-lang.org/

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