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

[ruby-core:120819] [Ruby master Bug#21097] `x = a rescue b in c` and `def f = a rescue b in c` parsed differently between parse.y and prism
by tompng (tomoya ishida) 11 Sep '25

11 Sep '25

Issue #21097 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #21097: `x = a rescue b in c` and `def f = a rescue b in c` parsed differently between parse.y and prism https://bugs.ruby-lang.org/issues/21097 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 3.5.0dev (2025-01-27T08:19:32Z master c3c7300b89) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ~~~ruby x = a rescue b in c (x = (a rescue b)) in c # parse.y, prism(ruby 3.4) x = (a rescue (b in c)) # prism(ruby 3.5) ~~~ ~~~ruby def f = a rescue b in c #=> true(parse.y), :f(prism) (def f = (a rescue b)) in c # parse.y def f = (a rescue (b in c)) # prism ~~~ There is no difference between prism and parse.y parsing these codes ~~~ruby a rescue b in c # a rescue (b in c) x = a rescue b # x = (a rescue b) x = b in c # (x = b) in c def f = a rescue b # def f = (a rescue b) def f = b in c # (def f = a) in b ~~~ -- https://bugs.ruby-lang.org/

7 8

[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/

9 23

[ruby-core:117618] [Ruby master Feature#20437] Could be the licensing conditions be made less ambiguous?
by vo.x (Vit Ondruch) 02 Sep '25

02 Sep '25

Issue #20437 has been reported by vo.x (Vit Ondruch). ---------------------------------------- Feature #20437: Could be the licensing conditions be made less ambiguous? https://bugs.ruby-lang.org/issues/20437 * Author: vo.x (Vit Ondruch) * Status: Open ---------------------------------------- # Current state The current [COPYING](https://github.com/ruby/ruby/blob/6cfd929034f1fe3d93160365505a8b88… file says the following: ~~~ Ruby is copyrighted free software by Yukihiro Matsumoto <matz(a)netlab.jp>. You can redistribute it and/or modify it under either the terms of the 2-clause BSDL (see the file BSDL), or the conditions below: 1. You may make and give away verbatim copies of the source form of the ... snip ... ~~~ And this is quite ambiguous. Let me show a few examples: # Ambiguous examples ## lib/net/protocol.rb https://github.com/ruby/ruby/blob/6cfd929034f1fe3d93160365505a8b88bef56159/… ~~~ # This program is free software. You can re-distribute and/or # modify this program under the same terms as Ruby itself, # Ruby Distribute License or GNU General Public License. ~~~ So what is the license? Is it 2-clause BSDL + Ruby + GPL? Or is is just Ruby + GPL but not 2-clause BSDL? ## Racc https://github.com/ruby/racc/blob/d52fb64d166046bfde81e6e9c424fcd884ebcabf/… ~~~ Racc is distributed under the same terms of ruby. (see the file COPYING). ~~~ where the [COPYING](https://github.com/ruby/racc/blob/d52fb64d166046bfde81e6e9c424fcd8… contains just 2-clause BSDL. Not even mentioning that Ruby used to be GPLv2 licensed: https://github.com/ruby/racc/commit/cc7fe952a6b1fc2ef43477674fa13f2d9d99e818 ## Rubygems https://github.com/rubygems/rubygems/blob/master/LICENSE.txt The license is obviously modeled after Ruby COPYING file, but if it could say "licensed under MIT or Ruby", it would be much better. ## Gettext https://github.com/ruby-gettext/gettext/blob/8d84132efd888e68fffbce41331645… The license note is so old that it is not obvious what that means and what was the intention. Did the Ruby relicensing from "GPLv2 or Ruby" to "GPLv2 or BSD" influenced this project? ## SPDX https://spdx.org/licenses/Ruby.html It quotes just the "conditions below" as a Ruby license, while referring to [Ruby license file](https://www.ruby-lang.org/en/about/license.txt) mentioning also 2-clause BSDL # Proposal To me it seems that the whole world recognizes "Ruby" license, except Ruby. Therefore I think it would be nice if Ruby project recognized the "Ruby" license. There are two possibilities I can think of: ## Refer the license by name ~~~diff $ git diff diff --git a/COPYING b/COPYING index 48e5a96de7..a2d179a8a9 100644 --- a/COPYING +++ b/COPYING @@ -1,6 +1,6 @@ Ruby is copyrighted free software by Yukihiro Matsumoto <matz(a)netlab.jp>. You can redistribute it and/or modify it under either the terms of the -2-clause BSDL (see the file BSDL), or the conditions below: +2-clause BSDL (see the file BSDL), or the conditions of the Ruby license below: 1. You may make and give away verbatim copies of the source form of the software without restriction, provided that you duplicate all of the ~~~ ## Extract the "conditions below" into "Ruby" license file The "conditions below" text could be extracted into separate file (e.g. "RUBY_LICENSE") and the "COPYING" file rephrased to say: ~~~ Ruby is copyrighted free software by Yukihiro Matsumoto <matz(a)netlab.jp>. You can redistribute it and/or modify it under either the terms of the 2-clause BSDL (see the file BSDL), or Ruby license (see the file RUBY_LICENSE) ~~~ -- https://bugs.ruby-lang.org/

2 5

[ruby-core:116083] [Ruby master Feature#20163] Introduce #bit_count method on Integer
by garrison (Garrison Jensen) 01 Sep '25

01 Sep '25

Issue #20163 has been reported by garrison (Garrison Jensen). ---------------------------------------- Feature #20163: Introduce #bit_count method on Integer https://bugs.ruby-lang.org/issues/20163 * Author: garrison (Garrison Jensen) * Status: Open * Priority: Normal ---------------------------------------- This feature request is to implement a method called #bit_count on Integer that returns the number of ones in the binary representation of the absolute value of the integer. ``` n = 19 n.bit_count #=> 3 (-n).bit_count #=> 3 ``` This is often useful when you use an integer as a bitmask and want to count how many bits are set. This would be equivalent to ``` n.to_s(2).count("1") ``` However, this can be outperformed by ``` def bit_count(n) count = 0 while n > 0 n &= n - 1 # Flip the least significant 1 bit to 0 count += 1 end count end ``` I think this would be a useful addition because it would fit alongside the other bit-related methods defined on integer: `#bit_length,` `#allbits?`, `#anybits?`, `#nobits?`. Also, when working with bitmasks, a minor upgrade to performance often results in a significant improvement. Similar methods from other languages: https://docs.python.org/3/library/stdtypes.html#int.bit_count https://doc.rust-lang.org/std/primitive.i32.html#method.count_ones -- https://bugs.ruby-lang.org/

10 18

[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 _) 30 Aug '25

30 Aug '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/

3 3

[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/

7 25

[ruby-core:112552] [Ruby master Bug#19461] Time.local performance tanks in forked process (on macOS only?)
by ioquatix (Samuel Williams) 23 Aug '25

23 Aug '25

Issue #19461 has been reported by ioquatix (Samuel Williams). ---------------------------------------- Bug #19461: Time.local performance tanks in forked process (on macOS only?) https://bugs.ruby-lang.org/issues/19461 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- The following program demonstrates a performance regression in forked child processes when invoking `Time.local`: ```ruby require 'benchmark' require 'time' def sir_local_alot result = Benchmark.measure do 10_000.times do tm = ::Time.local(2023) end end $stderr.puts result end sir_local_alot pid = fork do sir_local_alot end Process.wait(pid) ``` On Linux the performance is similar, but on macOS, the performance is over 100x worse on my M1 laptop. -- https://bugs.ruby-lang.org/

5 9

[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/

7 9

[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/

4 3

[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/

3 2