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

[ruby-core:111526] [Ruby master Bug#19288] Ractor JSON parsing significantly slower than linear parsing
by maciej.mensfeld (Maciej Mensfeld) 08 Sep '25

08 Sep '25

Issue #19288 has been reported by maciej.mensfeld (Maciej Mensfeld). ---------------------------------------- Bug #19288: Ractor JSON parsing significantly slower than linear parsing https://bugs.ruby-lang.org/issues/19288 * Author: maciej.mensfeld (Maciej Mensfeld) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-linux] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- a simple benchmark: ```ruby require 'json' require 'benchmark' CONCURRENT = 5 RACTORS = true ELEMENTS = 100_000 data = CONCURRENT.times.map do ELEMENTS.times.map do { rand => rand, rand => rand, rand => rand, rand => rand }.to_json end end ractors = CONCURRENT.times.map do Ractor.new do Ractor.receive.each { JSON.parse(_1) } end end result = Benchmark.measure do if RACTORS CONCURRENT.times do |i| ractors[i].send(data[i], move: false) end ractors.each(&:take) else # Linear without any threads data.each do |piece| piece.each { JSON.parse(_1) } end end end puts result ``` Gives following results on my 8 core machine: ```shell # without ractors: 2.731748 0.003993 2.735741 ( 2.736349) # with ractors 12.580452 5.089802 17.670254 ( 5.209755) ``` I would expect Ractors not to be two times slower on the CPU intense work. -- https://bugs.ruby-lang.org/

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[ruby-core:120694] [Ruby master Bug#21039] Ractor.make_shareable breaks block semantics (seeing updated captured variables) of existing blocks
by Eregon (Benoit Daloze) 27 Aug '25

27 Aug '25

Issue #21039 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Bug #21039: Ractor.make_shareable breaks block semantics (seeing updated captured variables) of existing blocks https://bugs.ruby-lang.org/issues/21039 * Author: Eregon (Benoit Daloze) * Status: Open * Assignee: ko1 (Koichi Sasada) * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ```ruby def make_counter count = 0 nil.instance_exec do [-> { count }, -> { count += 1 }] end end get, increment = make_counter reader = Thread.new { sleep 0.01 loop do p get.call sleep 0.1 end } writer = Thread.new { loop do increment.call sleep 0.1 end } ractor_thread = Thread.new { sleep 1 Ractor.make_shareable(get) } sleep 2 ``` This prints: ``` 1 2 3 4 5 6 7 8 9 10 10 10 10 10 10 10 10 10 10 10 ``` But it should print 1..20, and indeed it does when commenting out the `Ractor.make_shareable(get)`. This shows a given block/Proc instance is concurrently broken by `Ractor.make_shareable`, IOW Ractor is breaking fundamental Ruby semantics of blocks and their captured/outer variables or "environment". It's expected that `Ractor.make_shareable` can `freeze` objects and that may cause some FrozenError, but here it's not a FrozenError, it's wrong values being read. I think what should happen instead is that `Ractor.make_shareable` should create a new Proc and mutate that. However, if the Proc is inside some other object and not just directly the argument, that wouldn't work (like `Ractor.make_shareable([get])`). So I think one fix would to be to only accept Procs for `Ractor.make_shareable(obj, copy: true)`. FWIW that currently doesn't allow Procs, it gives `<internal:ractor>:828:in 'Ractor.make_shareable': allocator undefined for Proc (TypeError)`. I think the only other way, and I think it would be a far better way would be to not support making Procs shareable with `Ractor.make_shareable`. Instead it could be some new method like `isolated { ... }` or `Proc.isolated { ... }` or `Proc.snapshot_outer_variables { ... }` or so, only accepting a literal block (to avoid mutating/breaking an existing block), and that would snapshot outer variables (or require no outer variables like Ractor.new's block, or maybe even do `Ractor.make_shareable(copy: true)` on outer variables) and possibly also set `self` since that's anyway needed. That would make such blocks with different semantics explicit, which would fix the problem of breaking the intention of who wrote that block and whoever read that code, expecting normal Ruby block semantics, which includes seeing updated outer variables. Related: #21033 https://bugs.ruby-lang.org/issues/18243#note-5 Extracted from https://bugs.ruby-lang.org/issues/21033#note-14 -- https://bugs.ruby-lang.org/

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[ruby-core:120873] [Ruby master Bug#21111] RbConfig::CONFIG['CXX'] quietly set to "false" when Ruby cannot build C++ programs
by stanhu (Stan Hu) 22 Aug '25

22 Aug '25

Issue #21111 has been reported by stanhu (Stan Hu). ---------------------------------------- Bug #21111: RbConfig::CONFIG['CXX'] quietly set to "false" when Ruby cannot build C++ programs https://bugs.ruby-lang.org/issues/21111 * Author: stanhu (Stan Hu) * Status: Open * ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +YJIT +PRISM [arm64-darwin24] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- As reported in https://gitlab.com/gitlab-org/gitlab-development-kit/-/issues/2222 and https://trac.macports.org/ticket/70750, we've had numerous macOS users experience problems with compiling Ruby C++ extensions after upgrading to XCode 16. Users have had to fix their XCode setups and reinstall Ruby when this happens. It turns out that when Ruby can't build a CXX program, it essentially sets CXX to the `false` string. From https://github.com/ruby/ruby/blob/7317f96727725ca37ddb06011918deb841de371c/…: ``` AS_IF([test -n "${rb_there_is_in_fact_no_gplusplus_but_autoconf_is_cheating_us}"], [ AC_MSG_NOTICE([Test skipped due to lack of a C++ compiler.]) ], [test -n "${CXX}"], [ RUBY_WERROR_FLAG([ AC_MSG_CHECKING([whether CXXFLAGS is valid]) AC_LANG_PUSH(C++) AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <cstdio>]], [[]])], [AC_MSG_RESULT(yes)],[ AC_MSG_RESULT(no) # The message mentions CXXFLAGS, but CPPFLAGS might also affects. AC_MSG_WARN([something wrong with CXXFLAGS="$CXXFLAGS"]) CXX=false ``` This causes C++ extensions, such as `unf_ext`, to fail while attempting to compile native extensions. There are no error messages because `false` is executed, so users only see: ``` Installing unf_ext 0.0.8.2 with native extensions Gem::Ext::BuildError: ERROR: Failed to build gem native extension. current directory: /Users/myuser/.rvm/gems/ruby-3.3.7/gems/unf_ext-0.0.8.2/ext/unf_ext /Users/kerrizor/.rvm/rubies/ruby-3.3.7/bin/ruby extconf.rb checking for -lstdc++... yes creating Makefile current directory: /Users/myuser/.rvm/gems/ruby-3.3.7/gems/unf_ext-0.0.8.2/ext/unf_ext make DESTDIR\= sitearchdir\=./.gem.20250203-69237-u2oi17 sitelibdir\=./.gem.20250203-69237-u2oi17 clean current directory: /Users/myuser/.rvm/gems/ruby-3.3.7/gems/unf_ext-0.0.8.2/ext/unf_ext make DESTDIR\= sitearchdir\=./.gem.20250203-69237-u2oi17 sitelibdir\=./.gem.20250203-69237-u2oi17 compiling unf.cc make: *** [unf.o] Error 1 ``` `unf_ext` only checks whether `RbConfig::CONFIG['CXX']` is defined, not that it is `false`: https://github.com/knu/ruby-unf_ext/blob/c72a36d0a5ea9fe3950611b0f289fc68a2…. Questions: 1. Should CXX just be set to `nil`? Or should all C++ extensions be expected to check for `false`? The latter seems surprising to me. 2. Should there be a way to fail the Ruby build if a valid C++ compiler is not found? -- https://bugs.ruby-lang.org/

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[ruby-core:117216] [Ruby master Bug#20346] FiberScheduler.unblock not called by Thread#join when Thread body contains Ractor.take
by forthoney (Seong-Heon Jung) 21 Aug '25

21 Aug '25

Issue #20346 has been reported by forthoney (Seong-Heon Jung). ---------------------------------------- Bug #20346: FiberScheduler.unblock not called by Thread#join when Thread body contains Ractor.take https://bugs.ruby-lang.org/issues/20346 * Author: forthoney (Seong-Heon Jung) * Status: Open * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- When using a `Ractor.take` inside a different thread, `Thread#join` on the thread running `Ractor.take` fails to call `FiberScheduler.unblock`. The below code can replicate this behavior ```ruby require "async" class RactorWrapper def initialize @ractor = Ractor.new do Ractor.recv # Ractor doesn't start until explicitly told to # Do some calculations fib = ->(x) { x < 2 ? 1 : fib.call(x - 1) + fib.call(x - 2) } fib.call(20) end end def take_async @ractor.send(nil) Thread.new { @ractor.take }.join.value end end Async do |task| 10000.times do |i| task.async do RactorWrapper.new.take_async puts i end end end ``` The above code deadlocks, and when we leave a debugging print statement inside of `Async`'s scheduler's `block` and `unblock` method, we can confirm that we only call `Scheduler.block`, and never `Scheduler.unblock` -- https://bugs.ruby-lang.org/

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[ruby-core:112206] [Ruby master Bug#19407] 2 threads taking from current ractor will hang forever
by luke-gru (Luke Gruber) 21 Aug '25

21 Aug '25

Issue #19407 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #19407: 2 threads taking from current ractor will hang forever https://bugs.ruby-lang.org/issues/19407 * Author: luke-gru (Luke Gruber) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- In the current implementation of Ractors, it's possible to `take` from the current ractor. This could be useful when co-ordinating threads: ```ruby t = Thread.new do obj = Ractor.current.take p obj # do some work with obj end t0 = Thread.new do obj = Ractor.current.take p obj # do some work with obj end Ractor.yield :go ``` However it hangs forever: ```ruby t = Thread.new do obj = Ractor.current.take p obj end t0 = Thread.new do obj = Ractor.current.take p obj end sleep 0.5 ``` Should "self-take" be disabled, or was it designed to allow it but this is just a bug? -- https://bugs.ruby-lang.org/

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[ruby-core:115438] [Ruby master Misc#20013] Travis CI status
by jaruga (Jun Aruga) 15 Aug '25

15 Aug '25

Issue #20013 has been reported by jaruga (Jun Aruga). ---------------------------------------- Misc #20013: Travis CI status https://bugs.ruby-lang.org/issues/20013 * Author: jaruga (Jun Aruga) * Status: Open * Priority: Normal ---------------------------------------- I would like to use this ticket to manage our activities to report Travis CI status. Because there is Travis CI status page provided by Travis CI. However, even when the page shows ok, I actually see infra issues. https://www.traviscistatus.com/ I would share my activities and report the Travis CI status on the ticket. The ticket's status is not closed until we stop using Travis CI. The easiest option to fix the Travis infra issue is to email Travis CI support `support _AT_ travis-ci.com`. You can check [this ruby/ruby Travis CI wiki page](https://github.com/ruby/ruby/wiki/CI-Servers#travis-ci) for details. -- https://bugs.ruby-lang.org/

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[ruby-core:121136] [Ruby master Bug#21151] IO and StringIO raise FrozenError even for read-only methods
by headius (Charles Nutter) 11 Aug '25

11 Aug '25

Issue #21151 has been reported by headius (Charles Nutter). ---------------------------------------- Bug #21151: IO and StringIO raise FrozenError even for read-only methods https://bugs.ruby-lang.org/issues/21151 * Author: headius (Charles Nutter) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Problem -------- While fixing a small [regression](https://github.com/ruby/stringio/issues/119) from my recent StringIO [fixes](https://github.com/ruby/stringio/issues/116) I discovered that a large number of read-only methods will fail if the StringIO is frozen. A few examples: ``` $ ruby -rstringio -e 's = StringIO.new; p s.lineno; s.freeze; p s.lineno' 0 -e:1:in 'StringIO#lineno': can't modify frozen StringIO: #<StringIO:0x0000000103711ea8> (FrozenError) from -e:1:in '<main>' $ ruby -rstringio -e 's = StringIO.new; p s.closed?; s.freeze; p s.closed?' false -e:1:in 'StringIO#closed?': can't modify frozen StringIO: #<StringIO:0x00000001008c1e68> (FrozenError) from -e:1:in '<main>' $ ruby -rstringio -e 's = StringIO.new; p s.eof?; s.freeze; p s.eof?' true -e:1:in 'StringIO#eof?': can't modify frozen StringIO: #<StringIO:0x000000011c171e80> (FrozenError) from -e:1:in '<main>' $ ruby -rstringio -e 's = StringIO.new; p s.pos; s.freeze; p s.pos' 0 -e:1:in 'StringIO#pos': can't modify frozen StringIO: #<StringIO:0x0000000105551df0> (FrozenError) from -e:1:in '<main>' ``` @kou pointed out that IO also raises for at least `lineno` and suggested I re-open the issue here. I still believe these read-only operations should be allowed on frozen IO or StringIO. Cause in StringIO ----------------- This is because the `StringIO` macro calls `get_strio` which calls `rb_io_taint_check` which calls `rb_check_frozen`. The `StringIO` macro is used in almost every method to access the rb_stringio_t data structure. A list of methods I believe should be operable when the StringIO is frozen (in stringio.c definition order): * string (returns underlying String but does not mutate anything) * lineno * pos * closed?/closed_read?/closed_write? * eof/eof? * sync * pid (a dummy method but it writes nothing) * fileno (dummy) * pread (by definition does not modify state) * isatty/tty? * size/length * external_encoding * internal_encoding In addition, `initialize_copy` probably should not require the original StringIO to be writable: ``` $ ruby -rstringio -e 's = StringIO.new("foo"); s.freeze; p s.dup' -e:1:in 'StringIO#initialize_copy': can't modify frozen StringIO: #<StringIO:0x0000000102eb1df8> (FrozenError) from -e:1:in 'Kernel#initialize_dup' from -e:1:in 'Kernel#dup' from -e:1:in '<main>' ``` The data from the original StringIO is unmodified by `initialize_copy`, other than the reference-counting `ptr->count` (which should not be subject to frozen checks). Cause in IO ----------- The `GetOpenFile` macro calls `RB_IO_POINTER` macro which calls `rb_io_taint_check` which calls `rb_check_frozen`. Methods in IO that should work on a frozen IO include any of the above StringIO that currently raise. For example `lineno` uses `GetOpenFile`, but `fileno` does not and does not raise. There's clearly some inconsistency here we can clean up. Origin ------ I believe most of the StringIO cases are caused by this change from 2011 that added frozen checks to StringIO (the class and the macro): https://github.com/ruby/ruby/commit/d8d9bac5c8b071135e50ad3f21c8a9b6a9c06e54 In IO, this behavior dates way back to 2000 by @matz himself: https://github.com/ruby/ruby/commit/087c83d7ceed6893afff93066937fb570ae4a115 Notes ----- I have started to fix the StringIO cases for JRuby in https://github.com/ruby/stringio/pull/122. I could probably fix the C version of StringIO as well, but I'm a little more unsure about how to fix IO. -- https://bugs.ruby-lang.org/

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[ruby-core:111789] [Ruby master Feature#19333] Setting (Fiber Local|Thread Local|Fiber Storage) to nil should delete value in order to avoid memory leaks.
by ioquatix (Samuel Williams) 07 Aug '25

07 Aug '25

Issue #19333 has been reported by ioquatix (Samuel Williams). ---------------------------------------- Feature #19333: Setting (Fiber Local|Thread Local|Fiber Storage) to nil should delete value in order to avoid memory leaks. https://bugs.ruby-lang.org/issues/19333 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- As it stands, Fiber Locals, Thread Locals and Fiber Storage have no way of deleting key-value associations. ```ruby 100.times do |i| name = :"variable-#{i}" Thread.current[name] = 10 end ``` Because of this, dynamically generated associations can leak over time. This is worse for things like Threads that might be pooled (or maybe an argument against user-space pooling). In any case, having a way to delete those associations would allow application code to at least delete the associations when they no longer make sense. I propose that assigning `nil` to "locals" or "storage" should effectively delete them. e.g. ```ruby 100.times do |i| name = :"variable-#{i}" Thread.current[name] = 10 Thread.current[name] = nil # delete association end ``` A more invasive alternative would be to define new interfaces like `Thread::Local`, `Fiber::Local` and `Fiber::Storage::Local` (or something) which correctly clean up on GC. -- https://bugs.ruby-lang.org/

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[ruby-core:114590] [Ruby master Bug#19857] Eval coverage is reset after each `eval`.
by ioquatix (Samuel Williams) 06 Aug '25

06 Aug '25

Issue #19857 has been reported by ioquatix (Samuel Williams). ---------------------------------------- Bug #19857: Eval coverage is reset after each `eval`. https://bugs.ruby-lang.org/issues/19857 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * Assignee: ioquatix (Samuel Williams) * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- It seems like `eval` based coverage is reset every time eval is invoked. ```ruby #!/usr/bin/env ruby require 'coverage' def measure(flag) c = Class.new c.class_eval(<<~RUBY, "foo.rb", 1) def foo(flag) if flag puts "foo" else puts "bar" end end RUBY return c.new.foo(flag) end Coverage.start(lines: true, eval: true) # Depending on the order of these two operations, different computation is calculated, because the evaluation of the code is considered different, even if the content/path is the same. measure(false) measure(true) p Coverage.result ``` Further investigation is required. -- https://bugs.ruby-lang.org/

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[ruby-core:121054] [Ruby master Bug#21139] Prism and parse.y parses `it = it` differently
by tompng (tomoya ishida) 05 Aug '25

05 Aug '25

Issue #21139 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #21139: Prism and parse.y parses `it = it` differently https://bugs.ruby-lang.org/issues/21139 * Author: tompng (tomoya ishida) * Status: Assigned * Assignee: prism * ruby -v: ruby 3.5.0dev (2025-02-14T16:49:52Z master ee181d1bb7) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ~~~ # ruby --parser=parse.y -e "42.tap { it = it; p it }" nil # ruby --parser=prism -e "42.tap { it = it; p it }" 42 ~~~ -- https://bugs.ruby-lang.org/

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