December 2023 - ruby-core - ml.ruby-lang.org

[ruby-core:115016] [Ruby master Bug#19921] TestYJIT#test_bug_19316 test failure
by vo.x (Vit Ondruch) 03 Aug '26

03 Aug '26

Issue #19921 has been reported by vo.x (Vit Ondruch). ---------------------------------------- Bug #19921: TestYJIT#test_bug_19316 test failure https://bugs.ruby-lang.org/issues/19921 * Author: vo.x (Vit Ondruch) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0dev (2023-10-12 master 52709a4862) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Testing with 52709a4862 on Fedora Rawhide, I observe following failure: ~~~ 94) Failure: TestYJIT#test_bug_19316 [/builddir/build/BUILD/ruby-3.3.0-52709a4862/test/ruby/test_yjit.rb:1126]: Expected no exits, but got {:opt_and=>1} ~~~ -- https://bugs.ruby-lang.org/

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[ruby-core:112045] [Ruby master Bug#19378] Windows: Use less syscalls for faster require of big gems
by aidog (Andi Idogawa) 27 Jul '26

27 Jul '26

Issue #19378 has been reported by aidog (Andi Idogawa). ---------------------------------------- Bug #19378: Windows: Use less syscalls for faster require of big gems https://bugs.ruby-lang.org/issues/19378 * Author: aidog (Andi Idogawa) * Status: Open * Priority: Normal * ruby -v: 3.2.0 * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Hello 🙂 ## Problem require is slow on windows for big gems. (example: require 'gtk3'=> 3 seconds+). This is a problem for people who want to make cross platform GUI apps with ruby. ## Possible Reason As touched on in [#15797](https://bugs.ruby-lang.org/issues/15797) it seems like require uses realpath, which is emulated on windows. It checks every parent directory. The same syscalls run many times. ## Testfile C:\tmp\speedtest\testrequire.rb: ``` ruby require __dir__ + "/helloworld1.rb" require __dir__ + "/helloworld2.rb" ``` ``` shell ruby --disable-gems C:\tmp\speedtest\testrequire.rb ``` ### Syscalls per File/Directory: 1. CreateFile 2. QueryInformationVolume 3. QueryIdInformation 4. QueryAllInformationFile 5. QueryNameInformationFile 6. QueryNameInformationFile 7. QueryNormalizedNameInformationFile 8. CloseFile ### Files/Directories checked 1. C:\tmp 2. C:\tmp\speedtest 3. C:\tmp\speedtest\helloworld1.rb 4. C:\tmp 5. C:\tmp\speedtest 6. C:\tmp\speedtest\helloworld2.rb For two required files Ruby had to do 8*6 = **48** syscalls. The syscalls orginate from rb_w32_reparse_symlink_p / lstat Rubygems live in subfolders with 9+ parts: "C:\Ruby32-x64\lib\ruby\gems\3.2.0\gems\glib2-4.0.8\lib\glib2\variant.rb" Each file takes 8 * 9 = **72**+ calls. For variant.rb it is **80** calls. The result for the syscalls don't change in such a short time, so it should be possible to cache it. With require_relative it's twice as many calls. ## Other testcases Same result: ``` ruby File.realpath __dir__ + "/helloworld1.rb" File.realpath __dir__ + "/helloworld2.rb" ``` ``` ruby File.stat __dir__ + "/helloworld1.rb" File.stat __dir__ + "/helloworld2.rb" ``` It does not happen in $LOAD_PATH.resolve_feature_path(__dir__ + "/helloworld1.rb") ## Request Would it be possible to cache the stat calls when using require? I tried to implement a cache inside the ruby source code, but failed. If not, is there now a way to combine ruby files into one? I previously talked about require here: [YJIT: Windows support lacking.](https://bugs.ruby-lang.org/issues/19325#note-11) ## How to reproduce Ruby versions: At least 3.0+, most likely older ones too. Tested using Ruby Installer 3.1 and 3.2. [Procmon Software by Sysinternals](https://learn.microsoft.com/en-us/sysinternals/downloads/proc… -- https://bugs.ruby-lang.org/

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[ruby-core:115018] [Ruby master Bug#19922] ObjectSpace.dump_all in multiple threads in parallel causes SEGV
by wanabe (_ wanabe) 20 Jul '26

20 Jul '26

Issue #19922 has been reported by wanabe (_ wanabe). ---------------------------------------- Bug #19922: ObjectSpace.dump_all in multiple threads in parallel causes SEGV https://bugs.ruby-lang.org/issues/19922 * Author: wanabe (_ wanabe) * Status: Open * Priority: Normal * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- `ObjectSpace.dump_all` in multiple threads in parallel causes SEGV. The reproduce code is here: ``` $ ruby -robjspace -e 'def dump; 10.times { ObjectSpace.dump_all } end; Thread.new { dump }; dump' /home/wanabe/.rbenv/versions/master/lib/ruby/3.3.0+0/objspace.rb:100: [BUG] Segmentation fault at 0x0000000000000000 (snip) ``` I attached the full log. I assumed that: - Thread1 - calls `rb_objspace_reachable_objects_from_root()` - changes `GET_RACTOR()->mfd`: mfd1 - calls `dump_flush()` - changes current thread due to IO - Thread2 - calls `rb_objspace_reachable_objects_from_root()` - changes `GET_RACTOR()->mfd`: mfd2 - calls `dump_flush()` - changes current thread due to IO - Thread1 - gets unexpected `GET_RACTOR()->mfd`: mfd2 ---Files-------------------------------- bug.log (23.1 KB) -- https://bugs.ruby-lang.org/

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[ruby-core:113743] [Ruby master Feature#19708] Support `attr_reader :foo?`
by AMomchilov (Alexander Momchilov) 13 Jul '26

13 Jul '26

Issue #19708 has been reported by AMomchilov (Alexander Momchilov). ---------------------------------------- Feature #19708: Support `attr_reader :foo?` https://bugs.ruby-lang.org/issues/19708 * Author: AMomchilov (Alexander Momchilov) * Status: Open * Priority: Normal ---------------------------------------- Creating reader methods with `attr_reader` is preferable over defining them by hand, not only because it's more convenient, but also because it hits a fast path in MRI (see `VM_METHOD_TYPE_IVAR`). Since local and instance variables can't end with `?`, you can't use `attr_reader` to define predicate-style methods for boolean values, like: ```ruby class Person attr_reader(:name, :age, :active?) # invalid attribute name `active?' (NameError) def initialize @name = "Bob" @age = 30 @active = true end end ``` It would be nice if `attr_reader` (and friends) could behave like: ```ruby def active? = @active ``` (`attr_writer` and `attr_accessor` couldn't do the same, since `def active?=(new_value)` isn't valid, so they'd probably stick with `def active=(new_value)`) -- https://bugs.ruby-lang.org/

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[ruby-core:111678] [Ruby master Feature#19315] Lazy substrings in CRuby
by Eregon (Benoit Daloze) 07 Jul '26

07 Jul '26

Issue #19315 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Feature #19315: Lazy substrings in CRuby https://bugs.ruby-lang.org/issues/19315 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal ---------------------------------------- CRuby should implement lazy substrings, i.e., "abcdef"[1..3] must not copy bytes. Currently CRuby only reuse the char* if the substring is until the end of the buffer. But it should also work wherever the substring starts and ends. Yes, it means RSTRING_PTR() might need to allocate to \0-terminate, so be it, it's worth it. There is already code for this (`SHARABLE_MIDDLE_SUBSTRING`), but it's disabled by default and `RSTRING_PTR()` needs to be changed to deal with this. It seems a good idea to introduce a variant of `RSTRING_PTR` which doesn't guarantee \0-termination, so such callers can then use the existing bytes always without copy. There are countless workarounds for this missing optimization, all not worth and all less readable: * https://bugs.ruby-lang.org/issues/19314 * https://github.com/ruby/net-protocol/pull/14 * Manual lazy substrings which track string + index + length * More but I don't remember all now, feel free to comment or link more urls/tickets. -- https://bugs.ruby-lang.org/

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[ruby-core:115879] [Ruby master Bug#20081] Transfered Fiber doesn't return to Fiber that started it
by rmosolgo (Robert Mosolgo) 01 Jul '26

01 Jul '26

Issue #20081 has been reported by rmosolgo (Robert Mosolgo). ---------------------------------------- Bug #20081: Transfered Fiber doesn't return to Fiber that started it https://bugs.ruby-lang.org/issues/20081 * Author: rmosolgo (Robert Mosolgo) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin22] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Hi! I'm trying to figure out how to make sure that Fibers started with `.transfer` end up _terminated_, not just suspended. (If they're suspended, Rails thinks they're still alive, and they continue to hold onto database connections, see: https://github.com/rmosolgo/graphql-ruby/issues/4739#issuecomment-1866930914.) So, I'm looking for way to make sure that any Fiber I start with `.transfer` will be properly terminated. But what I noticed is that when a transfer-based Fiber terminates, it gives control back to the top-most Fiber, not the Fiber which transfered to it. Is this intended? Here's a script to replicate the issue: ```ruby manager = Fiber.new do parent = Fiber.current worker = Fiber.new do puts "2. Begin Worker" parent.transfer puts "4. End Worker" end puts "1. Transfer 1" worker.transfer puts "3. Transfer 2" worker.transfer puts "5. Finished manager" end manager.transfer puts "6. Finished script" ``` I expect the steps to print in order: ``` 1. Transfer 1 2. Begin Worker 3. Transfer 2 4. End Worker 5. Finished manager 6. Finished script ``` But instead, `5. ...` is skipped: ``` 1. Transfer 1 2. Begin Worker 3. Transfer 2 4. End Worker 6. Finished script ``` I think that's because my `worker` fiber terminates and passes control back to the top-level Fiber. Should it have passed control back to the `manager`? Or is there another way to make sure `worker` is terminated, and `manager` gets control? -- https://bugs.ruby-lang.org/

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[ruby-core:115165] [Ruby master Bug#19972] Install default/bundled gems into dedicated directories
by vo.x (Vit Ondruch) 15 Jun '26

15 Jun '26

Issue #19972 has been reported by vo.x (Vit Ondruch). ---------------------------------------- Bug #19972: Install default/bundled gems into dedicated directories https://bugs.ruby-lang.org/issues/19972 * Author: vo.x (Vit Ondruch) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0dev (2023-10-24 master c44d65427e) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- I think that the current situation, where the same directory (lets call it `Gem.default_dir`) is used for default/bundled gems as well as for user installed gems, is suboptimal. During the times, this has caused us quite some issue on Fedora. Historically, we redefined the `Gem.default_dir` to user home directory, to avoid the mixing of system gems and user installed gems. Unfortunately, with advent of default/bundled gems, we were facing issues that these gems were suddenly not listed, etc. I am realizing this issue in full once again since the "user install" RubyGems feature has landed [1]. I also think that we have arrived to this situation by evolution, not by design. Therefore my proposal is: Keep the `Gem.default_dir` for user `gem install`ed gems and lets install default and bundled gems into separate dedicated directories. Have separate `Gem.bundled_gems_dir` and `Gem.default_gems_dir` structures. Of course, if `Gem.default_dir == Gem.bundled_gems_dir == Gem.default_gems_dir`, we still can have the current layout. I have a simple POC here: https://github.com/ruby/ruby/pull/8761 BTW I have reported it here, because I think that RubyGems provides all it is needed. So it is not RubyGems ticket after all. However, I believe that RubyGems could benefit from this long term and some simplifications/cleanups would be possible. [1]: https://github.com/rubygems/rubygems/pull/5327 -- https://bugs.ruby-lang.org/

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[ruby-core:113430] [Ruby master Feature#19633] Allow passing block to `Kernel#autoload` as alternative to second `filename` argument
by shioyama (Chris Salzberg) 10 Jun '26

10 Jun '26

Issue #19633 has been reported by shioyama (Chris Salzberg). ---------------------------------------- Feature #19633: Allow passing block to `Kernel#autoload` as alternative to second `filename` argument https://bugs.ruby-lang.org/issues/19633 * Author: shioyama (Chris Salzberg) * Status: Open * Priority: Normal ---------------------------------------- `Kernel#autoload` takes two arguments, a symbol `module` representing the constant to be autoloaded, and a `filepath` to load the constant from (with `require`). Currently, Zeitwerk has to [monkeypatch `Kernel#require`](https://github.com/fxn/zeitwerk/blob/a7c4a983df0f4e4058f32c610dac1e8b99f687da/lib/zeitwerk/kernel.rb) to fetch the loader for the file being loaded, then run the original (aliased) `require`, then run autoload callbacks. In addition to the monkeypatch, this also requires a registry (`Zeitwerk::Registry`) to map file paths to loaders, to know which loader should be used for a given autoload-triggered `require`. In fact, Zeitwerk has to _assume_ that the monkey-patched `require` call came from an autoload trigger; there is no way to really be sure of the source. If Ruby allowed passing a block as an alternative to the explicit filepath, then I think this could be improved and would eliminate the need for a monkeypatch. So something like this: ```ruby autoload(:B) do require "lib/b" # trigger callback, etc end ``` I am implementing a gem called [Im](https://github.com/shioyama/im) which is a fork of Zeitwerk, and in the case of this gem, such a feature would be even more useful. Im implements autoloads on anonymous modules by registering an autoload and then "catching" the require and converting it into a `load`, passing the module as the second argument (see [here](https://github.com/shioyama/im/blob/44ce348639a1aae563a5be7a40602761e….) This is currently quite tricky because, again, it's hard to know _where_ a `require` came from. In addition to removing the monkeypatch (inherited from Zeitwerk), Im would further benefit from the block argument because then it could simply access the module via a closure, rather than pulling it from a registry: ```ruby mod.autoload(:Foo) do load "lib/foo.rb", mod end ``` I don't know how hard or easy this would be to implement, but if there is interest in this as a feature I'd be happy to look into implementing it. -- https://bugs.ruby-lang.org/

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[ruby-core:111146] [Ruby master Bug#19172] `ruby_thread_has_gvl_p` is innacurate sometimes -- document or change?
by ivoanjo (Ivo Anjo) 15 May '26

15 May '26

Issue #19172 has been reported by ivoanjo (Ivo Anjo). ---------------------------------------- Bug #19172: `ruby_thread_has_gvl_p` is innacurate sometimes -- document or change? https://bugs.ruby-lang.org/issues/19172 * Author: ivoanjo (Ivo Anjo) * Status: Open * Priority: Normal * ruby -v: (All Ruby versions) * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- Howdy 👋! I work for Datadog [on the ddtrace gem](https://github.com/DataDog/dd-trace-rb) and I found a... sharp edge on the internal `ruby_thread_has_gvl_p` API. I am aware that `ruby_thread_has_gvl_p` is documented an experimental API that is exported as a symbol but not present on the VM include files. ### Background In the ddtrace profiling component, we setup a signal handler and then periodically send SIGPROF signals to try to interrupt the running Ruby thread (e.g. the thread that is holding the global VM lock or equivalent). In the signal handler, we need to perform some API calls which are not safe to do without the GVL. So we need to check if the signal handler got called in the thread that has the GVL. ### The issue ```ruby int ruby_thread_has_gvl_p(void) { rb_thread_t *th = ruby_thread_from_native(); if (th && th->blocking_region_buffer == 0) { return 1; } else { return 0; } } ``` In its current implementation, `ruby_thread_has_gvl_p` only checks if the thread has a `blocking_region_buffer` or not. Unfortunately, this means that when called from a thread that lost the GVL but not due to blocking (e.g. via `rb_thread_schedule()`), it can still claim that a thread is holding the GVL when that is not the case. I ran into this issue in https://github.com/DataDog/dd-trace-rb/pull/2415, and needed to find a workaround. ### Next steps Since this is an internal VM API, I'm not sure you'd want to change the current behavior, so I was thinking of perhaps two options: * Is it worth changing `ruby_thread_has_gvl_p` to be accurate in the case I've listed? * If not, would you accept a PR to document its current limitations, so that others don't run into the same issue I did? -- https://bugs.ruby-lang.org/

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[ruby-core:115241] [Ruby master Bug#19986] Win32: `HOME` is set to just `HOMEDRIVE` if `HOMEPATH` is unset
by nobu (Nobuyoshi Nakada) 10 May '26

10 May '26

Issue #19986 has been reported by nobu (Nobuyoshi Nakada). ---------------------------------------- Bug #19986: Win32: `HOME` is set to just `HOMEDRIVE` if `HOMEPATH` is unset https://bugs.ruby-lang.org/issues/19986 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Priority: Normal * Backport: 3.0: REQUIRED, 3.1: REQUIRED, 3.2: REQUIRED ---------------------------------------- ``` $ env -u HOME -u USERPROFILE -u HOMEPATH HOMEDRIVE=no/such/home ./miniruby.exe -e 'p ENV["HOME"], Dir.home' "no/such/home" "no/such/home" ``` `HOMEDRIVE` should be ignored without `HOMEPATH`, and `HOME` should fallback to `CSIDL_PROFILE`. -- https://bugs.ruby-lang.org/

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