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

[ruby-core:122552] [Ruby Feature#21442] Make tsort to bundled gems
by hsbt (Hiroshi SHIBATA) 08 Jan '26

08 Jan '26

Issue #21442 has been reported by hsbt (Hiroshi SHIBATA). ---------------------------------------- Feature #21442: Make tsort to bundled gems https://bugs.ruby-lang.org/issues/21442 * Author: hsbt (Hiroshi SHIBATA) * Status: Open ---------------------------------------- In last year, I gave up to make `tsort` to bundled gems because `set` depends `tsort`. https://github.com/ruby/set/blob/29a253d2259e8d6d9b313dec8418ec5ed0caab08/l… Fortunately, `set` is now core class. So, there is no library depends on `tsort` in ruby repository. I propose to make `tsort` to bundled gems at the next release(not Ruby 3.5/4.0, for 4.0(?)/4.1) -- https://bugs.ruby-lang.org/

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[ruby-core:123453] [Ruby Bug#21634] Combining read(1) with eof? causes dropout of results unexpectedly on Windows.
by YO4 (Yoshinao Muramatsu) 08 Jan '26

08 Jan '26

Issue #21634 has been reported by YO4 (Yoshinao Muramatsu). ---------------------------------------- Bug #21634: Combining read(1) with eof? causes dropout of results unexpectedly on Windows. https://bugs.ruby-lang.org/issues/21634 * Author: YO4 (Yoshinao Muramatsu) * Status: Open * ruby -v: ruby 3.5.0dev (2025-10-03T08:59:54Z master 5b2ec0eb1b) +PRISM [x64-mingw-ucrt] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- On Windows, when reading a file containing EOF(\x1A), using read(1) with IO#eof? causes unexpected dropout of results. ```ruby irb(main):001> IO.binwrite("txt", "abcd\x1A") => 5 irb(main):002> open("txt", "r") { p _1.read(1) until _1.eof? }; # works fine "a" "b" "c" "d" "\x1A" irb(main):003> open("txt", "rt") { p _1.read(1) until _1.eof? }; # has failure "b" "d" irb(main):004> ``` The problem disappeared when I commented out one of the following lines (though this will break other things). * previous_mode = set_binary_mode_with_seek_cur(fptr); in io_read() * flush_before_seek(fptr, false); in set_binary_mode_with_seek_cur(() * io_unread(fptr, discard_rbuf); in flush_before_seek() Within io_unread(), rbuf.len should have changed as 5, 4, 3,... but instead changed as 4, 2,(end). Since inconsistencies already exist at this point, the problem appears to originate elsewhere. I found this in ruby master but the same issue was found at least in ruby-1.9.3-p551. -- https://bugs.ruby-lang.org/

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[ruby-core:121699] [Ruby Feature#21277] Windows ARM support
by hsbt (Hiroshi SHIBATA) 08 Jan '26

08 Jan '26

Issue #21277 has been reported by hsbt (Hiroshi SHIBATA). ---------------------------------------- Feature #21277: Windows ARM support https://bugs.ruby-lang.org/issues/21277 * Author: hsbt (Hiroshi SHIBATA) * Status: Open * Assignee: hsbt (Hiroshi SHIBATA) ---------------------------------------- I added the new CI job for Windows ARM support. * https://github.blog/changelog/2025-04-14-windows-arm64-hosted-runners-now-a… * https://github.com/ruby/ruby/pull/13118 We could build Ruby with Windows ARM platform. But `nmake check` is not working yet. I'm tracking that issues on this ticket. ## Can't generate `revision.h` `windows-11-arm` runner couldn't generate `revision.h` with `ruby tool/file2lastrev.rb --revision.h --output=revision.h`. I tried that with git provided by `scoop`. But that is also not working. I confirmed to work `git rev-parse HEAD` directly with `pwsh` of GitHub Actions. But `tool/file2lastrev.rb` returns the followings: ``` Run ruby tool/file2lastrev.rb --revision.h --output=revision.h file2lastrev.rb: git rev-parse failed fatal: unable to access 'NUL': Invalid argument ``` ## `nmake check` is not working https://github.com/ruby/ruby/actions/runs/14564201209/job/40851166866 ``` running file: C:/a/ruby/ruby/src/test/rubygems/test_gem_resolver_index_set.rb A test worker crashed. It might be an interpreter bug or a bug in test/unit/parallel.rb. Try again without the -j option. ``` https://github.com/ruby/ruby/actions/runs/14564667517/job/40852193517 ``` NMAKE : fatal error U1077: '@ .\ruby.exe -I../src/lib -I".ext/arm64-mswin64_140" -I. "../src/tool/runruby.rb" --extout=".ext" -- --disable-gems -r./arm64-mswin64_140-fake -r../src/tool/lib/_tmpdir ../src/spec/mspec/bin/mspec run -B ../src/spec/default.mspec ' : return code '0xc0000005' Stop. ``` They may be caused by Visual Studio 2022 issue same as #21255. -- https://bugs.ruby-lang.org/

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[ruby-core:120749] [Ruby master Feature#21084] Declare objects have weak references
by peterzhu2118 (Peter Zhu) 30 Dec '25

30 Dec '25

Issue #21084 has been reported by peterzhu2118 (Peter Zhu). ---------------------------------------- Feature #21084: Declare objects have weak references https://bugs.ruby-lang.org/issues/21084 * Author: peterzhu2118 (Peter Zhu) * Status: Open ---------------------------------------- # Summary The current way of marking weak references uses `rb_gc_mark_weak(VALUE *ptr)`. This presents challenges because Ruby's GC is incremental, meaning that if the `ptr` changes (e.g. realloc'd or free'd), then we could have an invalid memory access. This also overwrites `*ptr = Qundef` if `*ptr` is dead, which prevents any cleanup to be run (e.g. freeing memory or deleting entries from hash tables). This ticket proposes `rb_gc_declare_weak_references` which declares that an object has weak references and calls a cleanup function after marking, allowing the object to clean up any memory for dead objects. # Introduction In [[Feature #19783]](https://bugs.ruby-lang.org/issues/19783), I introduced an API allowing objects to mark weak references, the function signature looks like this: ```c void rb_gc_mark_weak(VALUE *ptr); ``` `rb_gc_mark_weak` is called during the marking phase of the GC to specify that the memory at `ptr` holds a pointer to a Ruby object that is weakly referenced. `rb_gc_mark_weak` appends this pointer to a list that is processed after the marking phase of the GC. If the object at `*ptr` is no longer alive, then it overwrites the object reference with a special value (`*ptr = Qundef`). However, this API resulted in two challenges: 1. Ruby's default GC is incremental, which means that the GC is not ran in one phase, but rather split into chunks of work that interleaves with Ruby execution. The `ptr` passed into `rb_gc_mark_weak` could be on the malloc heap, and that memory could be realloc'd or even free'd. We had to use workarounds such as `rb_gc_remove_weak` to ensure that there were no illegal memory accesses. This made `rb_gc_mark_weak` difficult to use, impacted runtime performance, and increased memory usage. 2. When an object dies, `rb_gc_mark_weak` only overwites the reference with `Qundef`. This means that if we want to do any cleanup (e.g. free a piece of memory or delete a hash table entry), we could not do that and had to defer this process elsewhere (e.g. during marking or runtime). # Declarative weak references In this ticket, I'm proposing a new API for weak references. Instead of an object marking its weak references during the marking phase, the object declares that it has weak references using the `rb_gc_declare_weak_references` function. This declaration occurs during runtime (e.g. after the object has been created) rather than during GC. After an object declares that it has weak references, it will have its callback function called after marking as long as that object is alive. This callback function can then call a special function `rb_gc_handle_weak_references_alive_p` to determine whether its references are alive. This will allow the callback function to do whatever it wants on the object, allowing it to perform any cleanup work it needs. This significantly simplifies the code for `ObjectSpace::WeakMap` and `ObjectSpace::WeakKeyMap` because it no longer needs to have the workarounds for the limitations of `rb_gc_mark_weak`. # Performance The performance results below demonstrate that `ObjectSpace::WeakMap#[]=` is now about 60% faster because the implementation has been simplified and the number of allocations has been reduced. We can see that there is not a significant impact on the performance of `ObjectSpace::WeakMap#[]`. Base: ``` ObjectSpace::WeakMap#[]= 4.620M (± 6.4%) i/s (216.44 ns/i) - 23.342M in 5.072149s ObjectSpace::WeakMap#[] 30.967M (± 1.9%) i/s (32.29 ns/i) - 154.998M in 5.007157s ``` Branch: ``` ObjectSpace::WeakMap#[]= 7.336M (± 2.8%) i/s (136.31 ns/i) - 36.755M in 5.013983s ObjectSpace::WeakMap#[] 30.902M (± 5.4%) i/s (32.36 ns/i) - 155.901M in 5.064060s ``` Code: ``` require "bundler/inline" gemfile do source "https://rubygems.org" gem "benchmark-ips" end wmap = ObjectSpace::WeakMap.new key = Object.new val = Object.new wmap[key] = val Benchmark.ips do |x| x.report("ObjectSpace::WeakMap#[]=") do |times| i = 0 while i < times wmap[Object.new] = Object.new i += 1 end end x.report("ObjectSpace::WeakMap#[]") do |times| i = 0 while i < times wmap[key] wmap[val] # does not exist i += 1 end end end ``` # Alternative designs Currently, `rb_gc_declare_weak_references` is designed to be an internal-only API. This allows us to assume the object types that call `rb_gc_declare_weak_references`. In the future, if we want to open up this API to third parties, we may want to change this function to something like: ```c void rb_gc_add_cleaner(VALUE obj, void (*callback)(VALUE obj)); ``` This will allow the third party to implement a custom `callback` that gets called after the marking phase of GC to clean up any dead references. I chose not to implement this design because it is less efficient as we would need to store a mapping from `obj` to `callback`, which requires extra memory. -- https://bugs.ruby-lang.org/

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[ruby-core:121234] [Ruby master Bug#21168] Prism doesn't require argument parentheses (in some cases) when a block is present but parse.y does
by Earlopain (Earlopain _) 28 Dec '25

28 Dec '25

Issue #21168 has been reported by Earlopain (Earlopain _). ---------------------------------------- Bug #21168: Prism doesn't require argument parentheses (in some cases) when a block is present but parse.y does https://bugs.ruby-lang.org/issues/21168 * Author: Earlopain (Earlopain _) * Status: Open * ruby -v: ruby 3.4.2 (2025-02-15 revision d2930f8e7a) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- It's a bit more than that but explaining it in full would be a bit much. Instead, see this: ```rb foo( bar baz do end ) ``` ```sh $ ruby -c --parser=prism test.rb Syntax OK $ ruby -c --parser=parse.y test.rb ruby: test.rb:2: syntax error, unexpected 'do' for block, expecting ')' (SyntaxError) bar baz do ^~ ``` OTOH, this is consistently rejected: ```rb [ foo bar do end, ] # And also foo || bar baz do end ``` -- https://bugs.ruby-lang.org/

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[ruby-core:118957] [Ruby master Bug#20699] On Windows, the `__dir__` keyword is garbled in paths containing Japanese characters, and `require_relative` fails as well
by flatland001 (Hayato Arai) 18 Dec '25

18 Dec '25

Issue #20699 has been reported by flatland001 (Hayato Arai). ---------------------------------------- Bug #20699: On Windows, the `__dir__` keyword is garbled in paths containing Japanese characters, and `require_relative` fails as well https://bugs.ruby-lang.org/issues/20699 * Author: flatland001 (Hayato Arai) * Status: Open * ruby -v: ruby 3.3.4 (2024-07-09 revision be1089c8ec) [x64-mingw-ucrt] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- In paths containing Japanese characters, such as: C:\テスト_test\test.rb Code: ``` ruby # this code -> C:\テスト_test\test.rb # external file -> C:\テスト_test\lib\foo.rb p __dir__ p __dir__.encoding p File.dirname(File.expand_path(__FILE__)) p File.dirname(File.expand_path(__FILE__)).encoding print "__dir__ == File.dirname(File.expand_path(__FILE__)): " p __dir__ == File.dirname(File.expand_path(__FILE__)) begin require_relative "lib/foo" puts "foo.rb loaded" rescue LoadError puts "LoadError: #{$!}" end ``` Results: ``` "C:/?e?X?g_test" #<Encoding:Windows-31J> "C:/\x{8365}\x{8358}\x{8367}_test" #<Encoding:Windows-31J> __dir__ == File.dirname(File.expand_path(__FILE__)): false LoadError: cannot load such file -- C:/?e?X?g_test/lib/foo ``` However, in ruby 3.2.5 (2024-07-26 revision 31d0f1a2e7) [x64-mingw-ucrt], the same code produces the following expected results: ``` "C:/\x{8365}\x{8358}\x{8367}_test" #<Encoding:Windows-31J> "C:/\x{8365}\x{8358}\x{8367}_test" #<Encoding:Windows-31J> __dir__ == File.dirname(File.expand_path(__FILE__)): true foo.rb loaded ``` Is this behavior expected, or could this be a bug in the Ruby interpreter on Windows? If this is my misunderstanding or a known issue, I apologize. Thank you for your consideration. Environment Information: - OS: Windows 11 Pro 23H2 (OS build 22631.4037) - Installed via: RubyInstaller - Shell: Command Prompt - File System: NTFS - System Locale: Japanese (Japan), Language: Japanese -- https://bugs.ruby-lang.org/

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[ruby-core:120743] [Ruby master Bug#21049] Reconsider handling of the numbered parameters and "it" parameter in `Binding#local_variables`
by mame (Yusuke Endoh) 18 Dec '25

18 Dec '25

Issue #21049 has been reported by mame (Yusuke Endoh). ---------------------------------------- Bug #21049: Reconsider handling of the numbered parameters and "it" parameter in `Binding#local_variables` https://bugs.ruby-lang.org/issues/21049 * Author: mame (Yusuke Endoh) * Status: Open * Assignee: matz (Yukihiro Matsumoto) * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Currently, `Binding#local_variable*` APIs wrongly handles the numbered parameters. ```ruby # Binding#local_variables includes numbered parameters that should not be visible "foo".tap do _1 "bar".tap do p binding.local_variables #=> expected: [], actual: [:_1] end end # Binding#local_variable_get can read numbered parameters that should not be readable "foo".tap do _1 "bar".tap do p binding.local_variable_get(:_1) #=> expected: NameError, actual: "foo" end end # Binding#local_variable_set can update numbered parameter "foo".tap do p _1 #=> "foo" binding.local_variable_set(:_1, "bar") # expected: NameError, actual: updates _1 p _1 #=> "bar" end ``` My proposal is to stop handling numbered parameters and "it" parameter in `Binding#local_variable*` APIs. ```ruby "foo".tap do _1 binding.local_variables #=> proposed: [] binding.local_variable_get(:_1) #=> proposed: NameError end ``` Here is a proof-of-concept patch. https://github.com/ruby/ruby/pull/12601 It would be theoretically possible to fix `Binding#local_variable*` APIs to handle numbered parameters while maintaining compatibility as much as possible. However, I think the implicit “it” parameter introduced in Ruby 3.4 poses a spec-level problem. This is because there is no way to distinguish between the implicit “it” parameter and a true local variable named "it". Also, I don't think numbered parameters are local variables, so I feel uncomfortable handling them by `Binding#local_variable*` APIs. If it is absolutely necessary to access numbered parameters or "it" parameter via binding, it would be good to introduce dedicated APIs for the purpose, as: * Binding#numbered_parameters #=> [:_1, :_2, :_3, ...] * Binding#numbered_parameter_get(:_1) #=> obj * Binding#numbered_parameter_defined?(:_1) #=> true or false * Binding#it_get #=> obj * Binding#it_defined? #=> true or false Personally, however, I do not see the need for these APIs currently. I implemented them as proof-of-concept in PR, but I am okay that they are not introduced. -- https://bugs.ruby-lang.org/

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[ruby-core:121252] [Ruby master Bug#21174] Range#max called with an argument on a beginless Integer Range raises RangeError
by andrykonchin (Andrew Konchin) 17 Dec '25

17 Dec '25

Issue #21174 has been reported by andrykonchin (Andrew Konchin). ---------------------------------------- Bug #21174: Range#max called with an argument on a beginless Integer Range raises RangeError https://bugs.ruby-lang.org/issues/21174 * Author: andrykonchin (Andrew Konchin) * Status: Open * ruby -v: 3.4.2 * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- It seems surprising but instead of returning last `n` Integers `Range#max(n)` raises `RangeError`: ```ruby (nil..10).max(2) # => (irb):3:in 'Range#max': cannot get the maximum of beginless range with custom comparison method (RangeError) ``` I would expect `[9, 10]` to be returned. -- https://bugs.ruby-lang.org/

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[ruby-core:120250] [Ruby master Feature#20953] Array#fetch_values vs #values_at protocols
by zverok (Victor Shepelev) 17 Dec '25

17 Dec '25

Issue #20953 has been reported by zverok (Victor Shepelev). ---------------------------------------- Feature #20953: Array#fetch_values vs #values_at protocols https://bugs.ruby-lang.org/issues/20953 * Author: zverok (Victor Shepelev) * Status: Open ---------------------------------------- I believe that the user might expect `#fetch_values` to be a stricter version of `#values_at`, confirming to the same protocol for arguments. But the current implementation for `#fetch_values` is simpler: ```ruby [1, 2, 3, 4, 5].values_at(0, 3..4) #=> [1, 4, 5] [1, 2, 3, 4, 5].fetch_values(0, 3..4) # TypeError: in 'Array#fetch': no implicit conversion of Range into Integer ``` I believe aligning the implementations would lessen confusion (even if it makes `#fetch_values` implementation somewhat less trivial). The practical example of usefulness: ```ruby HEADERS = %w[Name Department] def table_headers(rows) HEADERS.fetch_values(...rows.map(&:size).max) { '<unknown'> } # Or, alternatively: # HEADERS.fetch_values(...rows.map(&:size).max) { raise ArgumentError, "No header defined for column #{it + 1}" } end table_headers([ ['John'], ['Jane'], ]) #=> ["Name"] table_headers([ ['John'], ['Jane', 'Engineering'], ]) #=> ["Name", "Department"] table_headers([ ['John', 'Accounting', 'Feb 24'], ['Jane', 'Engineering'], ]) #=> ["Name", "Department", "<unknown>"] # or ArgumentError No header defined for column 3 ``` (Obviously, we can use `fetch_values(*(0...max_row_size))` as an argument, but it feels like an unjustified extra work when `values_at` already can do this.) -- https://bugs.ruby-lang.org/

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[ruby-core:123576] [Ruby Bug#21654] Set#new calls extra methods compared to previous versions
by tenderlovemaking (Aaron Patterson) 16 Dec '25

16 Dec '25

Issue #21654 has been reported by tenderlovemaking (Aaron Patterson). ---------------------------------------- Bug #21654: Set#new calls extra methods compared to previous versions https://bugs.ruby-lang.org/issues/21654 * Author: tenderlovemaking (Aaron Patterson) * Status: Open * ruby -v: ruby 3.5.0dev (2025-10-24T15:50:47Z master a9f24aaccb) +PRISM [arm64-darwin25] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- I'm trying to test Ruby 3.5.0 with our Rails application and we've found that `Set.new` is now causing extra database queries to happen. The changes in d4020dd5faf call "size" on enumerable objects that are passed to the `new` method, and this causes extra "COUNT" queries to happen with ActiveRecord associations. For example: ```ruby Set.new(some_activerecord_association) ``` Previously, the above code would only do one query by iterating over the association. Now it issues two queries, a count query, and then the normal query for results. Since d4020dd5faf is dealing with endless ranges, I would like to narrow the scope from all Enumerable objects to just Ranges. Unfortunately, I noticed we have a test like this: ```ruby assert_raise(ArgumentError) { Set.new(1.upto(Float::INFINITY)) } ``` I'm not sure how we can handle such a case without testing `size`. -- https://bugs.ruby-lang.org/

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