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

[ruby-core:120465] [Ruby master Bug#20998] rb_str_locktmp() changes flags of frozen strings and string literals
by Eregon (Benoit Daloze) 17 Jun '25

17 Jun '25

Issue #20998 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Bug #20998: rb_str_locktmp() changes flags of frozen strings and string literals https://bugs.ruby-lang.org/issues/20998 * Author: Eregon (Benoit Daloze) * Status: Open * ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ```ruby # frozen_string_literal: true # BOILERPLATE START require 'tmpdir' require 'rbconfig' def inline_c_extension(c_code) Dir.mktmpdir('inline_c_extension') do |dir| File.write("#{dir}/cext.c", c_code) File.write("#{dir}/extconf.rb", <<~RUBY) require 'mkmf' create_makefile('cext') RUBY out = IO.popen([RbConfig.ruby, 'extconf.rb'], chdir: dir, &:read) raise "ruby extconf.rb failed: #{$?.inspect}\n#{out}" unless $?.success? out = IO.popen(['make'], chdir: dir, &:read) raise "make failed: #{$?.inspect}\n#{out}" unless $?.success? require "#{dir}/cext.#{RbConfig::CONFIG['DLEXT']}" end end inline_c_extension <<~C #include "ruby.h" static VALUE foo(VALUE self, VALUE str) { rb_str_locktmp(str); return str; } void Init_cext(void) { VALUE c = rb_define_class("Foo", rb_cObject); rb_define_singleton_method(c, "foo", foo, 1); } C # BOILERPLATE END a = "str" # imagine a million line of codes in between b = "str" Foo.foo(a) b << "." # can't modify string; temporarily locked (RuntimeError) # What? Who "locked" that immutable frozen string literal? # It should be: can't modify frozen String: "str" (FrozenError) ``` Same problem with: ```ruby Foo.foo("abc") # imagine a million line of codes in between Foo.foo("abc") # emporal locking already locked string (RuntimeError) ``` Related: https://github.com/oracle/truffleruby/issues/3752 It seems a clear bug to mutate a frozen string (with visible side effects), even more so for shared frozen string literals. I think rb_str_locktmp() should raise (a FrozenError, as it's effectively attempting to mutate it, same as calling `rb_str_modify()`) if called on a frozen string, because it makes little sense, I think "locking a string" only makes sense for mutable strings. The alternative would be to noop on frozen strings for rb_str_locktmp() and rb_str_unlocktmp(), I think that's susprising, and potentially hiding more bugs, e.g. if one by mistake tries to mutate the RSTRING_PTR() or so. Any attempt to mutate a frozen string should fail, so might as well fail early. -- https://bugs.ruby-lang.org/

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[ruby-core:117684] [Ruby master Bug#20452] Ruby 3.3 on Alpine Linux results in a relatively shallow SystemStackError exception
by Earlopain (A S) 17 Jun '25

17 Jun '25

Issue #20452 has been reported by Earlopain (A S). ---------------------------------------- Bug #20452: Ruby 3.3 on Alpine Linux results in a relatively shallow SystemStackError exception https://bugs.ruby-lang.org/issues/20452 * Author: Earlopain (A S) * Status: Open * ruby -v: 3.3.1 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This is a redo of https://bugs.ruby-lang.org/issues/14387, reported against a non-eol version. The same issue still applies on recent rubies, though I personally only have tested 3.3 and 3.2: ```rb n = 100000 res = {} 1.upto(n).to_a.inject(res) do |r, i| r[i] = {} end def f(x) x.each_value { |v| f(v) } end f(res) ``` The patch from https://bugs.ruby-lang.org/issues/14387#note-13 still works, though as per https://bugs.ruby-lang.org/issues/14387#note-16 it can't be accepted as is. With the patch applied: ``` (irb):8:in `block in f': stack level too deep (SystemStackError) from (irb):8:in `each_value' from (irb):8:in `f' from (irb):8:in `block in f' from (irb):8:in `each_value' from (irb):8:in `f' from (irb):8:in `block in f' from (irb):8:in `each_value' from (irb):8:in `f' ... 11549 levels... from /usr/local/lib/ruby/gems/3.3.0/gems/irb-1.11.0/exe/irb:9:in `<top (required)>' from /usr/local/bin/irb:25:in `load' from /usr/local/bin/irb:25:in `<main>' ``` Without the patch: ``` (irb):8:in `each_value': stack level too deep (SystemStackError) from (irb):8:in `f' from (irb):8:in `block in f' from (irb):8:in `each_value' from (irb):8:in `f' from (irb):8:in `block in f' from (irb):8:in `each_value' from (irb):8:in `f' from (irb):8:in `block in f' ... 286 levels... from /usr/local/lib/ruby/gems/3.3.0/gems/irb-1.11.0/exe/irb:9:in `<top (required)>' from /usr/local/bin/irb:25:in `load' from /usr/local/bin/irb:25:in `<main>' ``` To reproduce, I have removed lines 102-105 from https://github.com/docker-library/ruby/blob/f5753434bb23041dd9913bb7b650e7b…. Check out the previous ticket for more information, there are a few conversations about possible solutions. -- https://bugs.ruby-lang.org/

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[ruby-core:120738] [Ruby master Bug#21048] [Prism] rescue in modifier form with condition behaves differently
by Earlopain (Earlopain _) 14 Jun '25

14 Jun '25

Issue #21048 has been reported by Earlopain (Earlopain _). ---------------------------------------- Bug #21048: [Prism] rescue in modifier form with condition behaves differently https://bugs.ruby-lang.org/issues/21048 * Author: Earlopain (Earlopain _) * Status: Open * ruby -v: 3.4.1 * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- With the following code there is a discrepancy in how prism and parse.y consider precedence: ```rb $called = false def foo $called = true end foo rescue nil if false puts "Called: #{$called}" ``` Prism interprets it as `(foo rescue nil) if false`, not calling the method. `parse.y` does `foo rescue (nil if false)` since at least Ruby 2.0 ```sh $ ruby -v ruby 3.5.0dev (2025-01-19T12:44:20Z master f27ed98eff) +PRISM [x86_64-linux] $ ruby code.rb Called: true $ ruby --parser=parse.y code.rb Called: false ``` -- https://bugs.ruby-lang.org/

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[ruby-core:118577] [Ruby master Bug#20631] Build failure with Xcode 16 beta and macOS 15 (Sequoia) Beta
by hsbt (Hiroshi SHIBATA) 11 Jun '25

11 Jun '25

Issue #20631 has been reported by hsbt (Hiroshi SHIBATA). ---------------------------------------- Bug #20631: Build failure with Xcode 16 beta and macOS 15 (Sequoia) Beta https://bugs.ruby-lang.org/issues/20631 * Author: hsbt (Hiroshi SHIBATA) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I found some issues with Xcode 16 beta and macOS 15 (Sequoia) Beta. `TestRubyOptions` and `TestVMDump` are failed with them. full log: https://gist.github.com/hsbt/378fe2ba47e734f2562ba9a154e1795b I'm not sure why macOS require `sudo` command for that. ---- And I and @katei also found the regression of https://bugs.ruby-lang.org/issues/18912#note-15. ``` >> pid = fork { p File.realpath "/" } >> Process.waitpid(pid) objc[82573]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called. objc[82573]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug. => 82573 ``` -- https://bugs.ruby-lang.org/

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[ruby-core:118412] [Ruby master Misc#20600] @ruby-lang.org has been migrated to Cloudflare
by shugo (Shugo Maeda) 10 Jun '25

10 Jun '25

Issue #20600 has been reported by shugo (Shugo Maeda). ---------------------------------------- Misc #20600: @ruby-lang.org has been migrated to Cloudflare https://bugs.ruby-lang.org/issues/20600 * Author: shugo (Shugo Maeda) * Status: Open ---------------------------------------- @ruby-lang.org has been migrated to Cloudflare, because ruby-lang.org was migrated from Google Domains to Squarespace, and Squarespace's e-mail forwarding doesn't work with custom MX records including subdomains:( I and Shibata-san are adding e-mail routing rules on Cloudflare, so if you have an e-mail address on ruby-lang.org, please verify the e-mail routing address when receiving an email from Cloudflare. -- https://bugs.ruby-lang.org/

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[ruby-core:119683] [Ruby master Feature#20861] Add an environment variable for tuning the default thread quantum
by tenderlovemaking (Aaron Patterson) 08 Jun '25

08 Jun '25

Issue #20861 has been reported by tenderlovemaking (Aaron Patterson). ---------------------------------------- Feature #20861: Add an environment variable for tuning the default thread quantum https://bugs.ruby-lang.org/issues/20861 * Author: tenderlovemaking (Aaron Patterson) * Status: Open ---------------------------------------- The default thread quantum is currently [hard coded at 100ms](https://github.com/ruby/ruby/blob/c7708d22c33040a74ea7ac683bf7407d37…. This can impact multithreaded systems that are trying to process Ruby level CPU bound work at the same time as IO work. I would like to add an environment variable `RUBY_THREAD_DEFAULT_QUANTUM_MS` that allows users to specify the default thread quantum (in milliseconds) via an environment variable. It defaults to our current default of 100ms. I've submitted the patch [here](https://github.com/ruby/ruby/pull/11981). Here is a Ruby program to demonstrate the problem: ```ruby def measure x = Process.clock_gettime(Process::CLOCK_MONOTONIC) yield Process.clock_gettime(Process::CLOCK_MONOTONIC) - x end def fib(n) if n < 2 n else fib(n-2) + fib(n-1) end end # find fib that takes ~500ms fib_i = 50.times.find { |i| measure { fib(i) } >= 0.05 } sleep_i = measure { fib(fib_i) } threads = [ Thread.new { 100.times { sleep(sleep_i) # sometimes stalled waiting for fib's quantum to finish } puts "done 1" }, Thread.new { 100.times { fib(fib_i) }; puts "done 2" }, ] # We expect the total time to be about 100 * sleep_i (~5 seconds) because # theoretically the sleep thread could be done nearly completely in parallel to # the fib thread. # # But because the `sleep` thread is iterating over the sleep call, it must wait # for the `fib` thread to complete its quantum, before it can start the next iteration. # # This means each sleep iteration could take up to `sleep_i + 100ms` # # We're calling that stalled time "waste" total = measure { threads.each(&:join) } waste = total - (sleep_i * 100) p TOTAL: total, WASTE: waste ``` The program has two threads. One thread is using CPU time by computing `fib` in a loop. The other thread is simulating IO time by calling `sleep` in a loop. When the `sleep` call completes, it can stall, waiting for the quantum in the fib thread to expire. That means that each iteration on sleep can actually take `sleep time + thread quantum`, or in this case ~600ms when we expected it to only take ~500ms. Ideally, the above program would take `500ms * 100` since all `sleep` calls should be able to execute in parallel with the `fib` calls. Of course this isn't true because the sleep thread must acquire the GVL before it can continue the next iteration, so there will always be _some_ overhead. This feature is for allowing people to tune that overhead. If we run this program with the default quantum the output looks like this: ``` $ ./miniruby -v fibtest.rb ruby 3.4.0dev (2024-11-01T14:49:50Z quantum-computing c7708d22c3) +PRISM [arm64-darwin24] done 2 done 1 {TOTAL: 12.672821999993175, WASTE: 4.960721996147186} ``` The output shows that our program spent about 5 seconds stalled, waiting to acquire the GVL. With this patch we can lower the default quantum, and the output is like this: ``` $ RUBY_THREAD_DEFAULT_QUANTUM_MS=10 ./miniruby -v fibtest.rb ruby 3.4.0dev (2024-11-01T22:06:35Z quantum-computing 087500643d) +PRISM [arm64-darwin24] done 2 done 1 {TOTAL: 8.898526000091806, WASTE: 1.4168260043952614} ``` Specifying the ENV to change the quantum to 10ms lowered our waste in the program to ~1.4 seconds. It's common for web applications to do mixed CPU and IO bound tasks in threads (see the Puma webserver), so it would be great if there was a way to customize the thread quantum depending on your application's workload. -- https://bugs.ruby-lang.org/

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[ruby-core:115981] [Ruby master Bug#20105] Introduce `IO::Stream` or something similar.
by ioquatix (Samuel Williams) 07 Jun '25

07 Jun '25

Issue #20105 has been reported by ioquatix (Samuel Williams). ---------------------------------------- Bug #20105: Introduce `IO::Stream` or something similar. https://bugs.ruby-lang.org/issues/20105 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * Assignee: ioquatix (Samuel Williams) * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Ruby's IO class has a general model for streaming IO, including some hidden classes like `IO::generic_readable` and `IO::generic_writable`. As Ruby's core IO classes evolve, gems like `openssl` (see `OpenSSL::Buffering`) need to be updated to support changes to the interface. As it stands, there are changes in `IO` which are not copied to `OpenSSL::Buffering`. I'd like to propose we introduce some shared interface for streams that is used by `IO`, `Socket`, and `OpenSSL` to start with. The general interface would be similar to `IO` and allow code like `OpenSSL` to avoid re-implementing the `IO` interface. -- https://bugs.ruby-lang.org/

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[ruby-core:121551] [Ruby Feature#21219] `Object#inspect` accept a list of instance variables to display
by byroot (Jean Boussier) 07 Jun '25

07 Jun '25

Issue #21219 has been reported by byroot (Jean Boussier). ---------------------------------------- Feature #21219: `Object#inspect` accept a list of instance variables to display https://bugs.ruby-lang.org/issues/21219 * Author: byroot (Jean Boussier) * Status: Open ---------------------------------------- ## Context The default `Object#inspect` implementation is quite useful to have a generic representation of objects in error message and similar places. However sometimes objects are referencing other objects with a very large `inspect` representation, making error message hard to understand. In some other cases, some instance variables are holding secrets such as password or private keys, and the default inspect behavior can cause these secrets to be leaked in logs among other places. You can of course define your own `inspect` implementation for any object, but it's not as simple as it may seems because you need to handle circular references, otherwise you can end up with a `SystemStackError`. Also, it's more minor, but since Ruby 2.7, you can no longer access an object's address, so you can't implement an `inspect` method that is consistent with `Object#inspect` From my experience, user defined implementations of `#inspect` are very rare, and I think the above is in part responsible. ## Feature I think it would be useful if the default `Object#inspect` implementation accepted a list of instance variables to display, so that you could very easily hide internal state, either because it's too verbose, or because it is secret: ```ruby require 'logger' logger = Logger.new(STDOUT) class DatabaseConfig def initialize(host, user, password) @host = host @user = user @password = password end def inspect = super(instance_variables: [:@host, :@user]) end env = {db_config: DatabaseConfig.new("localhost", "root", "hunter2")} logger.info("something happened, env: #{env}") ``` ``` INFO -- : something happened, env: {db_config: #<DatabaseConfig:0x00000001002b3a08 @host="localhost", @user="root">} ``` -- https://bugs.ruby-lang.org/

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[ruby-core:121182] [Ruby master Bug#21158] Ractor using 'receive_if' sits in busy wait when there are skipped messages in the incoming queue
by NeilW (Neil Wilson) 06 Jun '25

06 Jun '25

Issue #21158 has been reported by NeilW (Neil Wilson). ---------------------------------------- Bug #21158: Ractor using 'receive_if' sits in busy wait when there are skipped messages in the incoming queue https://bugs.ruby-lang.org/issues/21158 * Author: NeilW (Neil Wilson) * 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 ---------------------------------------- When using the conditional receive example from the Ractor documentation (either as a script, or within irb) <pre> r = Ractor.new do val = Ractor.receive_if{|msg| msg.is_a?(Array)} puts "Received successfully: #{val}" end r.send(1) r.send('test') </pre> ruby will sit in busy wait, pegging the processor at 100%, until it gets a message that matches the condition. Within irb it will often stop the REPL responding. The same problem occurs on ruby 3.02, 3.3.7 and 3.4.1 -- https://bugs.ruby-lang.org/

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[ruby-core:121443] [Ruby Bug#21198] Fiber::Scheduler#blocking_operation_wait crash due to stack-use-after-return
by peterzhu2118 (Peter Zhu) 06 Jun '25

06 Jun '25

Issue #21198 has been reported by peterzhu2118 (Peter Zhu). ---------------------------------------- Bug #21198: Fiber::Scheduler#blocking_operation_wait crash due to stack-use-after-return https://bugs.ruby-lang.org/issues/21198 * Author: peterzhu2118 (Peter Zhu) * Status: Open * Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONTNEED, 3.4: REQUIRED ---------------------------------------- The Fiber::Scheduler#blocking_operation_wait method is passed a proc through the `rb_fiber_scheduler_blocking_operation_wait` function. This function stack allocates the arguments used for the proc ([source](https://github.com/ruby/ruby/blob/2183899fd184ab1cfee80d57c0dd6f4dc…) If this proc is captured anywhere, then calling it again will illegally read from and write to stack space. The following script demonstrates this issue using the [test/fiber/scheduler.rb](https://github.com/ruby/ruby/blob/master/test/fibe… scheduler: ```ruby require_relative "test/fiber/scheduler" class MyScheduler < Scheduler def blocking_operation_wait(work) super $work = work end end scheduler = MyScheduler.new Fiber.set_scheduler(scheduler) require "tempfile" Fiber.schedule do file = Tempfile.new file.write("hello world!") $work.call end scheduler.run ``` Crashes with: ``` test.rb:19: [BUG] Bus Error at 0xce0f57696add0045 ruby 3.4.2 (2025-02-15 revision d2930f8e7a) +PRISM [arm64-darwin24] -- Crash Report log information -------------------------------------------- See Crash Report log file in one of the following locations: * ~/Library/Logs/DiagnosticReports * /Library/Logs/DiagnosticReports for more details. Don't forget to include the above Crash Report log file in bug reports. -- Control frame information ----------------------------------------------- c:0003 p:---- s:0010 e:000009 IFUNC c:0002 p:0017 s:0007 e:000006 BLOCK test.rb:19 [FINISH] c:0001 p:---- s:0003 e:000002 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- test.rb:19:in 'block in <main>' -- Threading information --------------------------------------------------- Total ractor count: 1 Ruby thread count for this ractor: 1 Note that the Fiber scheduler is enabled -- Machine register context ------------------------------------------------ x0: 0x000000010063a5f0 x1: 0x000000014b80ce00 x2: 0x0000000000000000 x3: 0x000000014b60f060 x4: 0x0000000000000000 x5: 0x0000000000000000 x6: 0x0000000000000004 x7: 0x0000000000000000 x18: 0x0000000000000000 x19: 0x000000014b6a4840 x20: 0xce0f57696add0045 x21: 0x000000010063a5f0 x22: 0x000000014b60f060 x23: 0x0000000000000000 x24: 0x000000014b60f998 x25: 0x0000000000014273 x26: 0x000000014b60f060 x27: 0x000000014b60f060 x28: 0x000000014b80ce00 lr: 0x0000000100d881d8 fp: 0x000000011bb039f0 sp: 0x000000011bb03980 -- C level backtrace information ------------------------------------------- SEGV received in BUS handler [1] 52599 abort ruby test.rb ``` -- https://bugs.ruby-lang.org/

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