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

[ruby-core:120840] [Ruby master Misc#21100] DevMeeting before or after RubyKaigi2025
by ko1 (Koichi Sasada) 09 May '25

09 May '25

Issue #21100 has been reported by ko1 (Koichi Sasada). ---------------------------------------- Misc #21100: DevMeeting before or after RubyKaigi2025 https://bugs.ruby-lang.org/issues/21100 * Author: ko1 (Koichi Sasada) * Status: Open ---------------------------------------- RubyKaigi 2025 will be at Matsuyama, Japan, Apr 16th - 18th. We would like to try to hold a face-to-face dev meeting at Matsuyama. (@matz will also participate!) * Date: 2025/04/15 (Tue.) 16:00-19:00 (The day before RubyKaigi) * Location: Ehime-ken Sogo Shakai Fukushi Kaikan, 3F Training room (in Japanese) 愛媛県総合社会福祉会館3F 研修室 ### How to participate Open to any RubyKaigi attendees who have a commit bit or who have a topic they particularly want to discuss. Please sign up on the doorkeeper page: https://rubyassociation.doorkeeper.jp/events/181721 The meeting will be held in a hackathon event. Please enjoy Ruby hacking with friends if you want before the meeting. Note: Do not forget to register RubyKaigi ticket too (see "[ruby-core:120816] Invitation to RubyKaigi 2025" from Akira). ### Program * 10:00am door open and start the Hackathon event * 3:00pm(?) Matz will arrive * 4:00pm opening and self introduction * 4:30pm discuss topics * 6:00pm closing and free time (closing time is depends on topics) * 7:00pm door close ### 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 2025/04/10. I'll ask Matz which should be discussed on this meeting and reorder them. - 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:121931] [Ruby Feature#15408] Deprecate ObjectSpace._id2ref
by byroot (Jean Boussier) 09 May '25

09 May '25

Issue #15408 has been updated by byroot (Jean Boussier). I was hoping for a removal timeline, but alright. I'll merge my PR. ---------------------------------------- Feature #15408: Deprecate ObjectSpace._id2ref https://bugs.ruby-lang.org/issues/15408#change-113041 * Author: headius (Charles Nutter) * Status: Assigned * Assignee: headius (Charles Nutter) ---------------------------------------- Ruby currently provides the object_id method to get a "identifier" for a given object. According to the documentation, this ID is the same for every object_id call against a given object, and guaranteed not to be the same as any other active (i.e. alive) object. However, no guarantee is made about the ID being reused for a future object after the original has been garbage collected. As a result, object_id can't be used to uniquely identify any object that might be garbage collected, since that ID may be associated with a completely different object in the future. Ruby also provides a method to go from an object_id to the object reference itself: ObjectSpace._id2ref. This method has been in Ruby for decades and is often used to implement a weak hashmap from ID to reference, since holding the ID will not keep the object alive. However due to the problems with object_id not actually being unique, it's possible for _id2ref to return a different object than originally had that ID as object slots are reused in the heap. The only way to implement object_id safely (with idempotency guarantees) would be to assign to all objects a monotonically-increasing ID. Alternatively, this ID could be assigned lazily only for those objects on which the code calls object_id. JRuby implements object_id in this way currently. The only way to implement _id2ref safely would be to have a mapping in memory from those monotonically-increasing IDs to the actual objects. This would have to be a weak mapping to prevent the objects from being garbage collected. JRuby currently only supports _id2ref via a flag, since the additional overhead of weakly tracking every requested object_id is extremely high. An alternative for MRI would be to implement _id2ref as a heap scan, as it is implemented in Rubinius. This would make it entirely unpractical due to the cost of scanning the heap for every ID lookup. I propose that both methods should immediately be deprecated for removal in Ruby 3.0. * They do not do what people expect. * They cannot reliably do what they claim to do. * They eventually lead to difficult-to-diagnose bugs in every possible use case. Put simply, both methods have always been broken in MRI and making them unbroken would render them useless. -- https://bugs.ruby-lang.org/

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[ruby-core:112091] [Ruby master Bug#19387] Issue with ObjectSpace.each_objects not returning IO objects after starting a ractor
by luke-gru (Luke Gruber) 09 May '25

09 May '25

Issue #19387 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #19387: Issue with ObjectSpace.each_objects not returning IO objects after starting a ractor https://bugs.ruby-lang.org/issues/19387 * Author: luke-gru (Luke Gruber) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- ```ruby r = Ractor.new do receive # block, the problem is not the termination of the ractor but the starting end ObjectSpace.each_object(IO) { |io| p io # we get no objects } ``` -- https://bugs.ruby-lang.org/

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[ruby-core:121927] [Ruby Bug#21314] Kernel#autoload requires the wrong file (?)
by mame (Yusuke Endoh) 09 May '25

09 May '25

Issue #21314 has been reported by mame (Yusuke Endoh). ---------------------------------------- Bug #21314: Kernel#autoload requires the wrong file (?) https://bugs.ruby-lang.org/issues/21314 * Author: mame (Yusuke Endoh) * Status: Open * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- While discussing #21154 with some people at the dev meeting, I found a weird behavior of `Kernel#autoload` that's hard to explain. I haven't yet looked at it carefully, but I was asked to create a ticket anyway. ```ruby # main.rb autoload :A, "./a" autoload :B, "./b" p A # fires the autoload of A ``` ```ruby # a.rb p :A1 B # fires the autoload of B class A end ``` ```ruby # b.rb p :B1 class B p :B2 p A # expected: requires no file (because a.rb is already being require'ed), and raises a NameError # actual: the autoload of B is fired (not A!), recursively (not no-op!) p :B3 end ``` ``` $ ruby main.rb :A1 :B1 :B2 :B1 # What? :B2 :A1 :A2 :A3 A :B3 b.rb:17:in '<class:B>': uninitialized constant B::A (NameError) ``` By the way, in this case, a.rb and b.rb are considered dependent each other. We need to consider how autoload should behave in this case. If it is the user's responsibility to avoid such a situation, we would like to be able to clearly explain what kind of situation should be avoided. -- https://bugs.ruby-lang.org/

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[ruby-core:121815] [Ruby Feature#21307] A way to strictly validate time input
by mame (Yusuke Endoh) 09 May '25

09 May '25

Issue #21307 has been reported by mame (Yusuke Endoh). ---------------------------------------- Feature #21307: A way to strictly validate time input https://bugs.ruby-lang.org/issues/21307 * Author: mame (Yusuke Endoh) * Status: Open ---------------------------------------- Currently, `Time.new` sometimes silently rolls over invalid date/time values: ```ruby Time.new(2025, 2, 29, 0, 0, 0, "+00:00") #=> 2025-03-01 00:00:00 Time.new(2025, 1, 1, 24, 0, 0, "+00:00") #=> 2025-01-02 00:00:00 Time.new(2025, 1, 1, 0, 0, 60, "+00:00") #=> 2025-01-01 00:01:00 ``` But in other cases, it raises `ArgumentError`: ```ruby Time.new(2025, 1, 32, 0, 0, 0, "+00:00") #=> argument out of range (ArgumentError) Time.new(2025, 1, 1, 24, 0, 1, "+00:00") #=> sec out of range (ArgumentError) Time.new(2025, 1, 1, 25, 0, 0, "+00:00") #=> hour out of range (ArgumentError) Time.new(2025, 1, 1, 0, 60, 0, "+00:00") #=> min out of range (ArgumentError) Time.new(2025, 1, 1, 0, 0, 61, "+00:00") #=> sec out of range (ArgumentError) ``` Is this inconsistency intentional? While automatic rollover can be useful, the current behavior feels unpredictable. --- If this is by design, I would like to propose a strict version, e.g. `Time.strict_new`, that raises an error for any invalid value: ```ruby Time.strict_new(2025, 2, 29, 0, 0, 0, "+00:00") #=> ArgumentError ``` Right now, the only workaround is to compare the input with the resulting object, which is clunky: ```ruby def time_strict_new(year, mon, day, hour, min, sec, zone) r = Time.strict_new(year, mon, day, hour, min, sec, zone) raise ArgumentError if r.year != year raise ArgumentError if r.mon != mon raise ArgumentError if r.day != day raise ArgumentError if r.hour != hour raise ArgumentError if r.min != min raise ArgumentError if r.sec != sec r end ``` In my case, I'm writing a TOML parser and need to reject invalid datetimes like `2100-02-29T15:15:15Z`. The rollover behavior gets in the way. -- https://bugs.ruby-lang.org/

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[ruby-core:121746] [Ruby Feature#21287] Remove SortedSet autoload and set/sorted_set
by jeremyevans0 (Jeremy Evans) 09 May '25

09 May '25

Issue #21287 has been reported by jeremyevans0 (Jeremy Evans). ---------------------------------------- Feature #21287: Remove SortedSet autoload and set/sorted_set https://bugs.ruby-lang.org/issues/21287 * Author: jeremyevans0 (Jeremy Evans) * Status: Open ---------------------------------------- When implementing core Set, I moved the `SortedSet` autoload from `lib/set.rb` to `prelude.rb`. However, since this autoload only works if the `sorted_set` gem is installed, I don't think it's a good idea to have in core. I would like to remove it. I've submitted a pull request that removes it: https://github.com/ruby/ruby/pull/13188 . I'm not sure whether people would prefer a deprecation warning before removal, to alert users who have the `sorted_set` gem installed and are relying on the autoload. Previously, the `SortedSet` autoload was only setup if you had already referenced `Set` to force loading `lib/set.rb`. So `Set; SortedSet` worked, but `SortedSet; Set` did not. If people would prefer a deprecation warning, I think it's fine to deprecate in 3.5 and remove in 3.6, and I can submit a separate pull request for that approach. -- https://bugs.ruby-lang.org/

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[ruby-core:121686] [Ruby Feature#21274] Show performance warnings for easily avoidable unnecessary implicit splat allocations
by jeremyevans0 (Jeremy Evans) 09 May '25

09 May '25

Issue #21274 has been reported by jeremyevans0 (Jeremy Evans). ---------------------------------------- Feature #21274: Show performance warnings for easily avoidable unnecessary implicit splat allocations https://bugs.ruby-lang.org/issues/21274 * Author: jeremyevans0 (Jeremy Evans) * Status: Open ---------------------------------------- In Ruby 3.4, I made many changes to reduce implicit allocations (mostly in method calling). There are still a few cases where Ruby must allocate an array for a positional splat, or a hash for a keyword splat. Some of these allocations are unavoidable, but in other cases, while Ruby cannot avoid the allocation, it is easy for a user to make a small change to their code to avoid the allocation. One example of this is when Ruby allocates to avoid an evaluation order issue. For example: ```ruby def kw = nil ary = [] m(*ary, kw:) ``` Ruby allocates an array for `*ary`, even though it does not need to, because `kw` is a method call, and the method call could potentially modify `ary` (it doesn't in this example, but Ruby's compiler cannot assume that, as the method may be overridden later). It is simple to avoid the allocation by using a local variable: ```ruby def kw = nil ary = [] kw = self.kw m(*ary, kw:) ``` To make it easier for users to find and avoid these unnecessary implicit allocations, I would like to add a performance warning in cases where Ruby allocates solely to avoid an evaluation order issue. I've submitted a pull request to implement this: https://github.com/ruby/ruby/pull/13135 The current warning messages in the pull request are quite verbose: ``` $ ruby -W:performance -e 'def kw; {} end; a = []; p(*a, **kw)' -e: warning: This method call implicitly allocates a potentially unnecessary array for the positional splat, because a keyword, keyword splat, or block pass expression could cause an evaluation order issue if an array is not allocated for the positional splat. You can avoid this allocation by assigning the related keyword, keyword splat, or block pass expression to a local variable and using that local variable. $ ruby -W:performance -e 'def b; ->{} end; h = {}; p(**h, &b)' -e: warning: This method call implicitly allocates a potentially unnecessary hash for the keyword splat, because the block pass expression could cause an evaluation order issue if a hash is not allocated for the keyword splat. You can avoid this allocation by assigning the block pass expression to a local variable, and using that local variable. ``` It may be desirable to shorten these messages, so I would appreciate suggestions. -- https://bugs.ruby-lang.org/

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[ruby-core:121921] [Ruby Feature#15408] Deprecate ObjectSpace._id2ref
by mame (Yusuke Endoh) 09 May '25

09 May '25

Issue #15408 has been updated by mame (Yusuke Endoh). This was discussed at the dev meeting, and @matz agreed to add the deprecation warning. ---------------------------------------- Feature #15408: Deprecate ObjectSpace._id2ref https://bugs.ruby-lang.org/issues/15408#change-113029 * Author: headius (Charles Nutter) * Status: Assigned * Assignee: headius (Charles Nutter) ---------------------------------------- Ruby currently provides the object_id method to get a "identifier" for a given object. According to the documentation, this ID is the same for every object_id call against a given object, and guaranteed not to be the same as any other active (i.e. alive) object. However, no guarantee is made about the ID being reused for a future object after the original has been garbage collected. As a result, object_id can't be used to uniquely identify any object that might be garbage collected, since that ID may be associated with a completely different object in the future. Ruby also provides a method to go from an object_id to the object reference itself: ObjectSpace._id2ref. This method has been in Ruby for decades and is often used to implement a weak hashmap from ID to reference, since holding the ID will not keep the object alive. However due to the problems with object_id not actually being unique, it's possible for _id2ref to return a different object than originally had that ID as object slots are reused in the heap. The only way to implement object_id safely (with idempotency guarantees) would be to assign to all objects a monotonically-increasing ID. Alternatively, this ID could be assigned lazily only for those objects on which the code calls object_id. JRuby implements object_id in this way currently. The only way to implement _id2ref safely would be to have a mapping in memory from those monotonically-increasing IDs to the actual objects. This would have to be a weak mapping to prevent the objects from being garbage collected. JRuby currently only supports _id2ref via a flag, since the additional overhead of weakly tracking every requested object_id is extremely high. An alternative for MRI would be to implement _id2ref as a heap scan, as it is implemented in Rubinius. This would make it entirely unpractical due to the cost of scanning the heap for every ID lookup. I propose that both methods should immediately be deprecated for removal in Ruby 3.0. * They do not do what people expect. * They cannot reliably do what they claim to do. * They eventually lead to difficult-to-diagnose bugs in every possible use case. Put simply, both methods have always been broken in MRI and making them unbroken would render them useless. -- https://bugs.ruby-lang.org/

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[ruby-core:112207] [Ruby master Bug#19408] Object no longer frozen after moved from a ractor
by luke-gru (Luke Gruber) 09 May '25

09 May '25

Issue #19408 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #19408: Object no longer frozen after moved from a ractor https://bugs.ruby-lang.org/issues/19408 * Author: luke-gru (Luke Gruber) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- I think frozen objects should still be frozen after a move. ```ruby r = Ractor.new do obj = receive p obj.frozen? # should be true but is false p obj end obj = [Object.new].freeze r.send(obj, move: true) r.take ``` -- https://bugs.ruby-lang.org/

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[ruby-core:121919] [Ruby Bug#17678] Ractors do not restart after fork
by jhawthorn (John Hawthorn) 08 May '25

08 May '25

Issue #17678 has been updated by jhawthorn (John Hawthorn). Status changed from Assigned to Closed Sorry @jeremyevans0 I think Aaron and I missed that PR, but we did the same thing in https://github.com/ruby/ruby/pull/12982 which should fix this. One thing we didn't do that's in your PR is forbid forking from within a Ractor, but that does seem like a prudent restriction (though it could be limiting for those wanting to fork, make some adjustments, exec) ---------------------------------------- Bug #17678: Ractors do not restart after fork https://bugs.ruby-lang.org/issues/17678#change-113027 * Author: ivoanjo (Ivo Anjo) * Status: Closed * Assignee: ractor * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Hello there! I'm working at Datadog on the `ddtrace` gem -- <https://github.com/DataDog/dd-trace-rb> and we're experimenting with using Ractors in our library but run into a few issues. ### Background When running a Ractor as a background process, the Ractor stops & does not restart when the application forks. ### How to reproduce (Ruby version & script) `ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-linux]` ```ruby r2 = Ractor.new do loop { puts "[#{Process.pid}] Ractor"; sleep(1) } end sleep(1) puts "[#{Process.pid}] Forking..." fork do sleep(5) puts "[#{Process.pid}] End fork." end loop do sleep(1) end ``` ### Expectation and result The application prints “Ractor” each second in the main process, but not in the fork. Expected the Ractor (defined as `r2`) to run in the fork. ``` [29] Ractor [29] Ractor [29] Forking... [29] Ractor [29] Ractor [29] Ractor [29] Ractor [29] Ractor [32] End fork. [29] Ractor [29] Ractor [29] Ractor ``` ### Additional notes Threads do not restart across forks either, so it might not be unreasonable to expect consistent behavior. However, it’s possible to detect a dead Thread and recreate it after a fork (e.g. with `#alive?`, `#status`), but there’s no such mechanism for Ractors. ### Suggested solutions 1. Auto-restart Ractors after fork 2. Add additional methods to Ractors that allow users to check & manage the status of the Ractor, similar to Thread. -- https://bugs.ruby-lang.org/

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