April 2026 - ruby-core - ml.ruby-lang.org

[ruby-core:125003] [Ruby Feature#21953] Allow accessing unshareable objects within a Ractor-local Ruby Box
by tikkss (Tsutomu Katsube) 09 May '26

09 May '26

Issue #21953 has been reported by tikkss (Tsutomu Katsube). ---------------------------------------- Feature #21953: Allow accessing unshareable objects within a Ractor-local Ruby Box https://bugs.ruby-lang.org/issues/21953 * Author: tikkss (Tsutomu Katsube) * Status: Open ---------------------------------------- ### Status Currently, non-main ractors prohibit access to the following objects to prevent data races: * Global variables * Class variables * Unshareable class instance variables * Unshareable constants ### Proposal I would like to propose that allow reading/writing unshareable objects inside a Ruby Box created in a non-main ractor: ```ruby # lib/x.rb class X # can write unshareable objects XXX = "1" @@cvar = "1" @ivar = "1" class << self def cvar; @@cvar; end def ivar; @ivar; end end end # can read unshareable objects $LOAD_PATH # => returns $LOAD_PATH includes lib directory X.cvar # => "1" X.ivar # => "1" X::XXX # => "1" # main.rb Ractor.new do local_box = Ruby::Box.new local_box.eval <<~RUBY base_dir = File.expand_path(File.dirname(__FILE__)) lib_dir = File.join(base_dir, "lib") # can write unshareable objects $LOAD_PATH.unshift(lib_dir) RUBY local_box.require("x") x = local_box::X.new end.join ``` Ruby Box can isolate global/class variables, class/module definitions from other boxes. A Ruby Box created inside a non-main ractor cannot be accessed from other ractor. If that is the case, wouldn’t it be fine to access unshareable objects inside that box? So I would like to propose that allow reading/writing unshareable objects inside a Ruby Box created in a non-main ractor. ### Background We are working on implementing a Ractor based parallel test runner for the test-unit gem. Ractor is a great for parallel processing. However, many existing libraries still rely on class variables or class instance variables for configuration. Ideally, we should reduce the use of class variables or class instance variables. Currently, we tried fixing several non-shareable objects, but we could not resolve all of them yet. We will continue working on this issue, but we are also exploring other approaches. This is the idea begind this proposal. I think the work needed to make objects shareable when running exisiting libraries with Ractor can be reduced. ### FAQ Q: Can we create a Ruby Box inside a non-main ractor? A: Yes: ```ruby Ractor.new {Ruby::Box.new}.join ``` Q: Is a Ruby Box created in a non-main ractor truly inaccessible from other ractor? A: No. I'm not sure if it's intentional, but a Ruby Box is a shareable object. Also, it can be accessed from the main Ractor by using `Ractor#value`: ```ruby Ractor.shareable?(Ruby::Box.new) # => true ``` ```ruby Ractor.new {Ruby::Box.new}.value # => #<Ruby::Box:3,user,optional> ``` To implement this proposal, Ruby Box may need to be an unshareable object, and passing it with `Ractor#value` may need to be disallowed. -- https://bugs.ruby-lang.org/

4 8

[ruby-core:125235] [Ruby Bug#21991] `$!` stays as the first exception in Ruby Box
by tikkss (Tsutomu Katsube) 08 May '26

08 May '26

Issue #21991 has been reported by tikkss (Tsutomu Katsube). ---------------------------------------- Bug #21991: `$!` stays as the first exception in Ruby Box https://bugs.ruby-lang.org/issues/21991 * Author: tikkss (Tsutomu Katsube) * Status: Open * ruby -v: ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [x86_64-darwin24] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- Description --- When Ruby Box is enabled (`RUBY_BOX=1`), `$!` inside `rescue` does not change after the first exception. `$!` is expected to show the exception for each `rescue` block, but it always shows the first one. Steps to reproduce --- ```ruby # test.rb begin raise "First error" rescue pp $! end begin raise "Second error" rescue pp $! end begin raise "Third error" rescue pp $! end ``` Expected result --- ```console $ RUBY_BOX=1 ruby test.rb ruby: warning: Ruby::Box is experimental, and the behavior may change in the future! See https://docs.ruby-lang.org/en/4.0/Ruby/Box.html for known issues, etc. #<RuntimeError: First error> #<RuntimeError: Second error> #<RuntimeError: Third error> ``` Actual result --- ```console $ RUBY_BOX=1 ruby test.rb ruby: warning: Ruby::Box is experimental, and the behavior may change in the future! See https://docs.ruby-lang.org/en/4.0/Ruby/Box.html for known issues, etc. #<RuntimeError: First error> #<RuntimeError: First error> #<RuntimeError: First error> ``` Additional information --- This issue does not reproduce when `RUBY_BOX=1` is not set: ```console $ ruby test.rb #<RuntimeError: First error> #<RuntimeError: Second error> #<RuntimeError: Third error> ``` Also, this issue does not reproduce when the exception object is captured explicitly in the `rescue` clause: ```ruby # test.rb begin raise "First error" rescue => e pp e end begin raise "Second error" rescue => e pp e end begin raise "Third error" rescue => e pp e end ``` ```console $ RUBY_BOX=1 ruby test.rb ruby: warning: Ruby::Box is experimental, and the behavior may change in the future! See https://docs.ruby-lang.org/en/4.0/Ruby/Box.html for known issues, etc. #<RuntimeError: First error> #<RuntimeError: Second error> #<RuntimeError: Third error> ``` -- https://bugs.ruby-lang.org/

2 2

[ruby-core:125377] [Ruby Bug#22018] ISeq created via `RubyVM::InstructionSequence.compile` don't support coverage
by byroot (Jean Boussier) 05 May '26

05 May '26

Issue #22018 has been reported by byroot (Jean Boussier). ---------------------------------------- Bug #22018: ISeq created via `RubyVM::InstructionSequence.compile` don't support coverage https://bugs.ruby-lang.org/issues/22018 * Author: byroot (Jean Boussier) * Status: Open * Backport: 3.3: WONTFIX, 3.4: REQUIRED, 4.0: REQUIRED ---------------------------------------- Reproduction: ```ruby require "coverage" File.write("/tmp/a.rb", <<~RUBY) module CoverableRaw def self.call "cover up" end end CoverableRaw.call RUBY Coverage.start require "/tmp/a.rb" p Coverage.result File.write("/tmp/b.rb", <<~RUBY) module Coverable def self.call "cover up" end end Coverable.call RUBY class RubyVM::InstructionSequence def self.load_iseq(path) compile_file(path) end end Coverage.start require "/tmp/b.rb" p Coverage.result ``` Expected: ```ruby {"/tmp/a.rb" => [1, 1, 1, nil, nil, nil, 1]} {"/tmp/b.rb" => [1, 1, 1, nil, nil, nil, 1]} ``` Actual: ```ruby {"/tmp/a.rb" => [1, 1, 1, nil, nil, nil, 1]} {} ``` Patch: https://github.com/ruby/ruby/pull/16805 -- https://bugs.ruby-lang.org/

2 3

[ruby-core:125150] [Ruby Bug#21970] Corrupted `ciobj->operands` in `compile.c: optimize_checktype`
by byroot (Jean Boussier) 04 May '26

04 May '26

Issue #21970 has been reported by byroot (Jean Boussier). ---------------------------------------- Bug #21970: Corrupted `ciobj->operands` in `compile.c: optimize_checktype` https://bugs.ruby-lang.org/issues/21970 * Author: byroot (Jean Boussier) * Status: Open * ruby -v: ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [aarch64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- A rare crash I observed in production. I unfortunately don't have a reproduction, but perhaps this will ring a bell to someone. ``` #4 0x0000aaaac9afb1b8 [PAC] in sigsegv (sig=11, info=0xaaaaff573e30, ctx=0xaaaaff573eb0) at signal.c:948 #5 <signal handler called> #6 0x0000aaaac9ddcb60 in get_next_insn (iobj=0xffffffff00000001) at compile.c:3078 #7 optimize_checktype (iobj=0xaaab00000640, iseq=0xffff6e41ac80) at compile.c:3291 #8 iseq_peephole_optimize (iseq=iseq@entry=0xffff6e41ac80, list=list@entry=0xaaab00000640, do_tailcallopt=do_tailcallopt@entry=0) at compile.c:3363 #9 0x0000aaaac9dde590 [PAC] in iseq_optimize (anchor=<optimized out>, iseq=<optimized out>) at compile.c:4453 #10 iseq_setup_insn (anchor=<optimized out>, iseq=<optimized out>) at compile.c:1648 #11 iseq_setup_insn (iseq=0xffff6e41ac80, anchor=0xffffdb42d078) at compile.c:1637 #12 0x0000aaaac9e22d34 [PAC] in pm_iseq_compile_node (iseq=0xffff6e41ac80, node=<optimized out>) at /ruby-4.0.2/prism_compile.c:10514 #13 0x0000aaaac9a32f08 [PAC] in pm_iseq_new_with_opt_try (d=d@entry=281474360333120) at iseq.c:1106 #14 0x0000aaaac99c81bc [PAC] in rb_protect (proc=proc@entry=0xaaaac9a32eec <pm_iseq_new_with_opt_try>, data=data@entry=281474360333120, pstate=pstate@entry=0xffffdb42d3e4) at eval.c:1127 #15 0x0000aaaac9a39408 [PAC] in pm_iseq_new_with_opt (node=node@entry=0xffffdb42d510, name=name@entry=281472546599520, path=path@entry=281472531544280, realpath=281472531544280, first_lineno=first_lineno@entry=215, parent=parent@entry=0x0, isolated_depth=isolated_depth@entry=0, type=type@entry=ISEQ_TYPE_METHOD, option=0xffffdb42d328, error_state=error_state@entry=0xffffdb42d3e4) at iseq.c:1159 #16 0x0000aaaac9dcf1fc [PAC] in pm_new_child_iseq (iseq=iseq@entry=0xffff6e41b068, node=node@entry=0xffffdb42d510, name=281472546599520, parent=parent@entry=0x0, type=type@entry=ISEQ_TYPE_METHOD, line_no=215) at /ruby-4.0.2/iseq.h:154 #17 0x0000aaaac9e0688c [PAC] in pm_compile_node (iseq=iseq@entry=0xffff6e41b068, node=0xaaab000f0ac0, ret=ret@entry=0xffffdb42dcd8, popped=popped@entry=true, scope_node=scope_node@entry=0xffffdb42e170) at /ruby-4.0.2/prism_compile.c:9073 #18 0x0000aaaac9e0bd7c [PAC] in pm_compile_node (iseq=iseq@entry=0xffff6e41b068, node=0xaaab000eeed0, ret=ret@entry=0xffffdb42dcd8, popped=popped@entry=false, scope_node=scope_node@entry=0xffffdb42e170) at /ruby-4.0.2/prism_compile.c:10327 #19 0x0000aaaac9e1ee4c [PAC] in pm_compile_scope_node (iseq=iseq@entry=0xffff6e41b068, scope_node=scope_node@entry=0xffffdb42e170, ret=ret@entry=0xffffdb42dcd8, popped=popped@entry=false, node_location=<optimized out>, node_location=<optimized out>) at /ruby-4.0.2/prism_compile.c:7047 ``` ``` (gdb) f 7 #7 optimize_checktype (iobj=0xaaab00000640, iseq=0xffff6e41ac80) at compile.c:3291 3291 ciobj = (INSN *)get_next_insn((INSN*)OPERAND_AT(ciobj, 0)); (gdb) p (INSN*)ciobj->operands[0] $7 = (INSN *) 0xffffffff00000001 (gdb) p *(INSN*)ciobj->operands[0] Cannot access memory at address 0xffffffff00000001 ``` -- https://bugs.ruby-lang.org/

2 3

[ruby-core:124714] [Ruby Bug#21870] Regexp: Warnings when using multiple non-overlapping \p{...} classes
by jneen (Jeanine Adkisson) 03 May '26

03 May '26

Issue #21870 has been reported by jneen (Jeanine Adkisson). ---------------------------------------- Bug #21870: Regexp: Warnings when using multiple non-overlapping \p{...} classes https://bugs.ruby-lang.org/issues/21870 * Author: jneen (Jeanine Adkisson) * Status: Open * ruby -v: 4.0.0, 4.0.1, earlier versions to a lesser extent * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- ```ruby $VERBOSE = true # warning: character class has duplicated range: /[\p{Word}\p{S}]/ regex = /[\p{Word}\p{S}]/ ``` As far as I can tell this is a perfectly valid and non-overlapping set of unicode properties, but I am still being spammed with warnings. Using `/(\p{Word}|\p{S})/` is kind of a workaround, but it is slower. -- https://bugs.ruby-lang.org/

9 22

[ruby-core:125265] [Ruby Feature#21998] Add {Method,UnboundMethod,Proc}#source_range
by Eregon (Benoit Daloze) 02 May '26

02 May '26

Issue #21998 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Feature #21998: Add {Method,UnboundMethod,Proc}#source_range https://bugs.ruby-lang.org/issues/21998 * Author: Eregon (Benoit Daloze) * Status: Open ---------------------------------------- I'm using matz's suggestion almost as-is from https://bugs.ruby-lang.org/issues/6012#note-53. The only change is the proposed class name. ## Use Cases Use cases have been discussed extensively and matz said: > The use cases are real and I want to support them So I think we don't need to discuss that anymore :) ## Background Adding column and last line information to `#source_location` is deemed too incompatible given the usages of `obj.source_location.last` which expect the start line (they would get the end column instead). ## Proposal So instead we add a new method, `{Method,UnboundMethod,Proc}#source_range`, which returns a `Ruby::SourceRange` and has these methods: * `start_line`: 1-indexed (same as `source_location.first`) * `end_line`: 1-indexed * `start_column`: in bytes, 0-indexed, I think `start_byte_column` could be good for extra clarity * `end_column`: in bytes, 0-indexed, I think `end_byte_column` could be good for extra clarity * `inspect` which shows something like `#<Ruby::SourceRange (1,0)-(2,10)>`. For the edge case of a heredoc spanning further than the end of a method/block, we would not include it in the `end_line` & `end_column` methods, but instead document it and provide a small code snippet in the docs to compute that if desired with Prism. ## Alternative An alternative could be a `Ruby::SourceLocation` class and `obj.source_location(object: true)`/`obj.source_location(extended: true)` but it feels less nice. Since we are designing something new I think it's best to go for the cleanest design. ## Consistency The above methods match the name of methods on `Prism::Node` and have the same semantics, which is good for consistency and to avoid confusion. ## Scope The scope is intentionally minimal to keep the discussion focused. ## Implementation I'm happy to implement this, it should be pretty trivial and very similar to the extended `source_location`. I would prefer to get an approval for this feature before implementing. -- https://bugs.ruby-lang.org/

6 18

[ruby-core:124655] [Ruby Bug#21856] Nokogiri performance degradation since Ruby 4.0
by ahorek 30 Apr '26

30 Apr '26

Issue #21856 has been reported by ahorek (Pavel Rosický). ---------------------------------------- Bug #21856: Nokogiri performance degradation since Ruby 4.0 https://bugs.ruby-lang.org/issues/21856 * Author: ahorek (Pavel Rosický) * Status: Open * ruby -v: ruby 4.1.0dev (2026-01-31T09:41:30Z master 7ef8c470d2) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- Loofah sanitization is noticeably slower ``` Ruby: 3.4.8 Loofah: 2.25.0 Nokogiri: 1.19.0 Iterations: 100000 user system total real Loofah.fragment + scrub!(:prune) 26.091872 0.000000 26.091872 ( 25.110925) Loofah.scrub_fragment(:prune) 25.913185 0.010392 25.923577 ( 24.948464) Nokogiri HTML parse only 3.852690 0.000000 3.852690 ( 3.705930) Ruby: 4.0.0 & 4.0.1 Loofah: 2.25.0 Nokogiri: 1.19.0 Iterations: 100000 user system total real Loofah.fragment + scrub!(:prune) 38.094207 0.041753 38.135960 ( 36.669463) Loofah.scrub_fragment(:prune) 40.168795 0.000045 40.168840 ( 38.561806) Nokogiri HTML parse only 4.012936 0.052024 4.064960 ( 3.913272) Ruby: 4.1.0 (ruby 4.1.0dev (2026-01-31T09:41:30Z master 7ef8c470d2) +PRISM [x86_64-linux]) Loofah: 2.25.0 Nokogiri: 1.19.0 Iterations: 100000 user system total real Loofah.fragment + scrub!(:prune) 39.004228 0.000000 39.004228 ( 37.694873) Loofah.scrub_fragment(:prune) 39.043199 0.031284 39.074483 ( 37.182785) Nokogiri HTML parse only 3.889100 0.010427 3.899527 ( 3.741622) ``` Originally reported https://www.redmine.org/issues/43737 ---Files-------------------------------- benchmark.rb (1002 Bytes) -- https://bugs.ruby-lang.org/

9 14

[ruby-core:125327] [Ruby Bug#22009] ERROR: AddressSanitizer: attempting to call malloc_usable_size() for pointer which is not owned: with ASAN and DEBUG enabled build
by yahonda (Yasuo Honda) 29 Apr '26

29 Apr '26

Issue #22009 has been reported by yahonda (Yasuo Honda). ---------------------------------------- Bug #22009: ERROR: AddressSanitizer: attempting to call malloc_usable_size() for pointer which is not owned: with ASAN and DEBUG enabled build https://bugs.ruby-lang.org/issues/22009 * Author: yahonda (Yasuo Honda) * Status: Open * Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- ### Background I am using ruby-head built and deployed by https://github.com/ruby/ruby-dev-builder for my repository. https://github.com/rsim/oracle-enhanced/blob/master/.github/workflows/ruby_… Recently, the `ruby-head` version has not been updated since `ruby 4.1.0dev (2026-03-29T05:57:51Z :detached: f9175a9e5f) +PRISM [aarch64-linux]`. According to the ruby-dev-builder log file: - The last successful build : https://github.com/ruby/ruby-dev-builder/actions/runs/23716940676 - The first failing build :https://github.com/ruby/ruby-dev-builder/actions/runs/23763490942 - The latest failing build : https://github.com/ruby/ruby-dev-builder/actions/runs/24686105004 ### Steps to reproduce ``` mkdir work cd work git clone https://github.com/ruby/ruby.git git clone https://github.com/ruby/ruby-dev-builder.git cd ruby ../ruby-dev-builder/asan_libs.rb \ --prefix=$HOME/.rubies/ruby-asan \ --cc=clang \ --cflags='-fsanitize=address -fno-omit-frame-pointer -ggdb3 -O3' \ --ldflags="-Wl,-rpath=$HOME/.rubies/ruby-asan/lib" \ --makeopts=-j4 export cppflags="-DENABLE_PATH_CHECK=0 -DRUBY_DEBUG=1 -DVM_CHECK_MODE=1 -DUSE_MN_THREADS=0" export optflags="-O3 -fno-omit-frame-pointer" export debugflags="-fsanitize=address -ggdb3" export CC=clang export cflags="-I$HOME/.rubies/ruby-asan/include" export LDFLAGS="-L$HOME/.rubies/ruby-asan/lib -Wl,-rpath=$HOME/.rubies/ruby-asan/lib" export RUBY_TEST_TIMEOUT_SCALE=5 ./autogen.sh ./configure --prefix=$HOME/.rubies/ruby-asan --enable-shared --disable-install-doc --enable-yjit make -j4 && make install make test-spec MSPECOPT="spec/ruby/library/objectspace/dump_all_spec.rb" 2>&1 | tee error.log ``` ### Expected behavior This spec should pass. ### Actual behavior It raises `ERROR: AddressSanitizer: attempting to call malloc_usable_size() for pointer which is not owned:` -- https://bugs.ruby-lang.org/

2 4

[ruby-core:125352] [Ruby Bug#22016] ruby segfaults regularly
by wiz (Thomas Klausner) 29 Apr '26

29 Apr '26

Issue #22016 has been reported by wiz (Thomas Klausner). ---------------------------------------- Bug #22016: ruby segfaults regularly https://bugs.ruby-lang.org/issues/22016 * Author: wiz (Thomas Klausner) * Status: Open * ruby -v: ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [x86_64-netbsd] * Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN ---------------------------------------- When using ruby 4.0.2 on NetBSD-11.99.5/x86_64, built from pkgsrc, I often get core dumps. Recently it was quite easy to get them using asciidoctor to build the documentation for vms-empire (but that is just one example). Here is the backtrace of the latest coredump: ``` GNU gdb (GDB) 17.1 Copyright (C) 2025 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64--netbsd". Type "show configuration" for configuration details. For bug reporting instructions, please see: <https://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from ruby40... ⚠️ warning: exec file is newer than core file. [New process 29975] [New process 316] Core was generated by `ruby40'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00007af7bc25f99a in _lwp_kill () from /usr/lib/libc.so.12 [Current thread is 1 (process 29975)] #0 0x00007af7bc25f99a in _lwp_kill () from /usr/lib/libc.so.12 #1 0x00007af7bc926422 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=sig@entry=11, ctx=ctx@entry=0x7af7a1f6e420, fmt=fmt@entry=0x7af7bca2ec38 "Segmentation fault at %p") at error.c:1135 #2 0x00007af7bc7d2406 in sigsegv (sig=11, info=0x7af7a1f6e3a0, ctx=0x7af7a1f6e420) at signal.c:948 #3 <signal handler called> #4 each_location (x=0x7f7fff7c3000, n=338431, cb=cb@entry=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>, data=0x0) at gc.c:2682 #5 0x00007af7bc6a955b in each_location_ptr (data=0x0, start=<optimized out>, end=<optimized out>, cb=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>) at gc.c:2691 #6 each_location_ptr (start=<optimized out>, end=<optimized out>, cb=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>, data=0x0) at gc.c:2688 #7 rb_gc_mark_machine_context (ec=0x7af7bc023650) at gc.c:2978 #8 mark_current_machine_context (ec=0x7af7bc023650) at gc.c:2958 #9 rb_gc_mark_roots (objspace=<optimized out>, categoryp=0x0) at gc.c:3056 #10 mark_roots (objspace=<optimized out>, categoryp=0x0) at gc/default/default.c:4629 #11 0x00007af7bc6bd047 in gc_marks_start (objspace=0x7af7bc018000, full_mark=<optimized out>) at gc/default/default.c:5815 #12 gc_marks (objspace=0x7af7bc018000, full_mark=<optimized out>) at gc/default/default.c:5831 #13 gc_start (objspace=objspace@entry=0x7af7bc018000, reason=<optimized out>, reason@entry=256) at gc/default/default.c:6516 #14 0x00007af7bc6bdd17 in heap_prepare (objspace=0x7af7bc018000, heap=0x7af7bc018028) at gc/default/default.c:2086 #15 heap_next_free_page (objspace=0x7af7bc018000, heap=0x7af7bc018028) at gc/default/default.c:2301 #16 newobj_cache_miss (objspace=0x7af7bc018000, cache=0x7af7bc000000, heap_idx=0, vm_locked=vm_locked@entry=false) at gc/default/default.c:2408 #17 0x00007af7bc6be719 in newobj_alloc (objspace=<optimized out>, cache=<optimized out>, heap_idx=<optimized out>, vm_locked=false) at gc/default/default.c:2432 #18 rb_gc_impl_new_obj (objspace_ptr=<optimized out>, cache_ptr=<optimized out>, klass=135203969407320, flags=8218, wb_protected=<optimized out>, alloc_size=<optimized out>) at gc/default/default.c:2511 #19 newobj_of (cr=<optimized out>, klass=135203969407320, flags=8218, shape_id=0, wb_protected=<optimized out>, size=<optimized out>) at gc.c:996 #20 0x00007af7bc84fcca in svar_new (obj=<optimized out>) at vm_insnhelper.c:642 #21 lep_svar_set (ec=0x7af7bc023650, lep=0x7af7bbefe6a0, key=key@entry=1, val=val@entry=4) at vm_insnhelper.c:656 #22 0x00007af7bc860c19 in vm_cfp_svar_set (ec=<optimized out>, cfp=<optimized out>, key=1, val=4) at vm.c:2014 #23 0x00007af7bc7983f9 in rb_reg_search_set_match (re=re@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, reverse=reverse@entry=0, set_backref_str=set_backref_str@entry=-1, set_match=set_match@entry=0x7f7fff7bea60) at re.c:1795 #24 0x00007af7bc798707 in rb_reg_search0 (re=re@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, reverse=reverse@entry=0, set_backref_str=set_backref_str@entry=-1, match=match@entry=0x7f7fff7bea60) at re.c:1857 #25 0x00007af7bc7ef856 in rb_pat_search0 (pat=pat@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, set_backref_str=set_backref_str@entry=-1, match=match@entry=0x7f7fff7bea60) at string.c:6167 #26 0x00007af7bc7febcf in str_gsub (argc=<optimized out>, argv=<optimized out>, str=135203969420880, bang=0) at string.c:6352 #27 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe310, calling=<optimized out>, argc=1, argv=0x7af7bbefe6b0, stack_bottom=0x7af7bbefe6a8) at vm_insnhelper.c:3902 #28 0x00007af7bc865da4 in vm_sendish (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe310, cd=0x7af7a0a0f8b0, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450 #29 0x00007af7bc86c200 in vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:856 #30 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825 #31 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801 #32 0x00007af7bc874d19 in invoke_iseq_block_from_c (ec=<optimized out>, captured=<optimized out>, self=<optimized out>, argc=<optimized out>, argv=<optimized out>, kw_splat=<optimized out>, passed_block_handler=<optimized out>, cref=0x4, is_lambda=<optimized out>, me=0x0) at vm.c:1820 #33 0x00007af7bc87628e in vm_yield_with_cref (ec=<optimized out>, argc=1, argv=0x7f7fff7beec8, kw_splat=0, cref=0x0, is_lambda=0) at vm.c:1865 #34 vm_yield (ec=<optimized out>, argc=1, argv=0x7f7fff7beec8, kw_splat=0) at vm.c:1879 #35 rb_yield_0 (argc=1, argv=0x7f7fff7beec8) at vm_eval.c:1362 #36 rb_yield (val=<optimized out>) at vm_eval.c:1378 #37 0x00007af7bc6c2366 in each_value_i (key=<optimized out>, value=<optimized out>, _=<optimized out>) at hash.c:3033 #38 0x00007af7bc6c3d42 in hash_foreach_iter () at hash.c:1269 #39 0x00007af7bc7ddb73 in st_general_foreach (tab=<optimized out>, func=0x7af7bc6c3d1b <hash_foreach_iter>, replace=0x0, arg=140187723886960, check_p=1) at st.c:1564 #40 0x00007af7bc6c4c9c in hash_foreach_call (arg=140187723886960) at hash.c:1396 #41 0x00007af7bc69a725 in rb_ec_ensure (ec=0x7af7bc023650, b_proc=<optimized out>, data1=<optimized out>, e_proc=0x7af7bc6c224a <hash_foreach_ensure>, data2=135203970494680) at eval.c:1146 #42 0x00007af7bc69a8dc in rb_ensure (b_proc=<optimized out>, data1=<optimized out>, e_proc=<optimized out>, data2=<optimized out>) at eval.c:1163 #43 0x00007af7bc6c734c in rb_hash_foreach (hash=hash@entry=135203970494680, func=func@entry=0x7af7bc6c2345 <each_value_i>, farg=farg@entry=0) at hash.c:1420 #44 0x00007af7bc6c8404 in rb_hash_each_value (hash=135203970494680) at hash.c:3061 #45 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe3b8, calling=<optimized out>, argc=0, argv=0x7af7bbefe638, stack_bottom=0x7af7bbefe630) at vm_insnhelper.c:3902 #46 0x00007af7bc865da4 in vm_sendish (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe3b8, cd=0x7af7a0ab1c60, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450 #47 0x00007af7bc86c200 in vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:856 #48 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825 #49 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801 #50 0x00007af7bc6fd247 in require_internal (ec=ec@entry=0x7af7bc023650, fname=<optimized out>, fname@entry=135203969759680, exception=exception@entry=1, warn=<optimized out>) at load.c:1341 #51 0x00007af7bc6fd2ef in rb_require_string_internal (fname=135203969759680, resurrect=resurrect@entry=false) at load.c:1451 #52 0x00007af7bc6fdcd8 in rb_require_string (fname=<optimized out>) at load.c:1437 #53 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe460, calling=<optimized out>, argc=1, argv=0x7af7bbefe5e0, stack_bottom=0x7af7bbefe5d8) at vm_insnhelper.c:3902 #54 0x00007af7bc86b8fd in vm_sendish (ec=<optimized out>, reg_cfp=<optimized out>, cd=<optimized out>, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450 #55 vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:904 #56 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825 #57 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801 #58 0x00007af7bc6fd247 in require_internal (ec=ec@entry=0x7af7bc023650, fname=<optimized out>, fname@entry=135203970210040, exception=exception@entry=1, warn=<optimized out>) at load.c:1341 #59 0x00007af7bc6fd2ef in rb_require_string_internal (fname=135203970210040, resurrect=resurrect@entry=false) at load.c:1451 #60 0x00007af7bc6fdcd8 in rb_require_string (fname=<optimized out>) at load.c:1437 #61 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe4d0, calling=<optimized out>, argc=1, argv=0x7af7bbefe580, stack_bottom=0x7af7bbefe578) at vm_insnhelper.c:3902 #62 0x00007af7bc86b8fd in vm_sendish (ec=<optimized out>, reg_cfp=<optimized out>, cd=<optimized out>, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450 #63 vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:904 #64 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825 #65 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801 #66 0x00007af7bc7c30ba in ruby_init_prelude () at ruby.c:1779 #67 ruby_opt_init (opt=opt@entry=0x7f7fff7c09d0) at ruby.c:1829 #68 0x00007af7bc7c5038 in ruby_opt_init (opt=0x7f7fff7c09d0) at ruby.c:1799 #69 prism_script (opt=0x7f7fff7c09d0, result=0x7f7fff7c0188) at ruby.c:2234 #70 process_options (argc=6, argc@entry=8, argv=0x7f7fff7c0c08, argv@entry=0x7f7fff7c0bf8, opt=0x7f7fff7c09d0) at ruby.c:2569 #71 0x00007af7bc7c54e0 in ruby_process_options (argc=argc@entry=8, argv=argv@entry=0x7f7fff7c0bf8) at ruby.c:226 #72 0x00007af7bc69b894 in ruby_options (argc=argc@entry=8, argv=argv@entry=0x7f7fff7c0bf8) at eval.c:119 #73 0x0000000000a045e3 in rb_main (argc=8, argv=0x7f7fff7c0bf8) at ./main.c:42 #74 main (argc=<optimized out>, argv=<optimized out>) at ./main.c:62 [?2004h(gdb) quit [?2004l ``` -- https://bugs.ruby-lang.org/

2 4

[ruby-core:124726] [Ruby Feature#21871] Add Module#undef_const
by jeremyevans0 (Jeremy Evans) 29 Apr '26

29 Apr '26

Issue #21871 has been reported by jeremyevans0 (Jeremy Evans). ---------------------------------------- Feature #21871: Add Module#undef_const https://bugs.ruby-lang.org/issues/21871 * Author: jeremyevans0 (Jeremy Evans) * Status: Open ---------------------------------------- I propose to add `Module#undef_const`, which would operate for constants similarly to how `undef_method` (and the `undef` keyword) works for methods. When an undefed constant is found during constant lookup, lookup stops, and results in `const_missing` being called (similar to how `undef_method` stops method lookup and results in `method_missing` being called). The expected use for this is for stopping direct access to global constants inside namespaces. For example: ```ruby class DangerousClass; end class SafeClass undef_const :DangerousClass DangerousClass # NameError (const_missing behavior) end DangerousClass # no error ``` You cannot implement this behavior without introducing the equivalent of `Module#undef_const`. The best you can do is define a constant in the namespace that raises later when there is some access to the returned object. However, that approach has significant limitations, since you cannot raise on the lookup, only later when something operates on the returned object: ```ruby class DangerousClass; end class SafeClass DangerousClass = BasicObject.new DangerousClass.foo # NoMethodError DangerousClass::Constant # TypeError def m # doesn't raise, NoMethodError/TypeError occurs potentially much later in unrelated code [DangerousClass] end end ``` As to why it is good to stop direct access to a particular constants inside a namespace, it helps avoid IDOR (insecure direct object reference) security issues, since it pushes you to use a style like: ```ruby # Find a bar related to this foo bar = foo.bars.find { it.id == some_id } ``` As opposed to: ```ruby bar = Bar.find { it.id == some_id && it.foo.id == foo.id } ``` Assuming these are equivalent, the first approach is still better, because it avoids the possibility that a developer can write the following, missing the necessary check that the bar being accessed is related to the foo: ```ruby bar = Bar.find { it.id == some_id } ``` By using `undef_const :Bar` in the namespace, the `Bar.find` approach will not work, and developers will be pushed to use the `foo.bars.find` approach, which enforces safer behavior. I've submitted a pull request that implements this proposal: https://github.com/ruby/ruby/pull/16116 -- https://bugs.ruby-lang.org/

4 4