November 2022 - ruby-core - ml.ruby-lang.org

[ruby-core:111027] [Ruby master Bug#19154] Specify require and autoload guarantees in ractors
by fxn (Xavier Noria) 14 Jul '25

14 Jul '25

Issue #19154 has been reported by fxn (Xavier Noria). ---------------------------------------- Bug #19154: Specify require and autoload guarantees in ractors https://bugs.ruby-lang.org/issues/19154 * Author: fxn (Xavier Noria) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.0preview3 (2022-11-27) [x86_64-darwin22] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- Given a file `c.rb`: ```ruby class C end ``` the following script: ```ruby r1 = Ractor.new do require './c.rb' end r2 = Ractor.new do require './c.rb' end r1.take r2.take ``` raises: ``` % ruby -v foo.rb ruby 3.2.0preview3 (2022-11-27) [x86_64-darwin22] foo.rb:1: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues. #<Thread:0x000000010fee2928 run> terminated with exception (report_on_exception is true): #<Thread:0x00000001102acfe0 run> terminated with exception (report_on_exception is true): <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:164:in `ensure in require': can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:167:in `require' from foo.rb:6:in `block in <main>' <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:37:in `require'<internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:164:in `ensure in require': : can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:167:in `require' can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from foo.rb:2:in `block in <main>' <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:37:in `require': can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from foo.rb:2:in `block in <main>' from foo.rb:6:in `block in <main>' <internal:ractor>:698:in `take': thrown by remote Ractor. (Ractor::RemoteError) from foo.rb:9:in `<main>' <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:164:in `ensure in require': can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:167:in `require' from foo.rb:2:in `block in <main>' <internal:/Users/fxn/.rbenv/versions/3.2.0-preview3/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb>:37:in `require': can not access non-shareable objects in constant Kernel::RUBYGEMS_ACTIVATION_MONITOR by non-main ractor. (Ractor::IsolationError) from foo.rb:2:in `block in <main>' ``` Would it be possible to have documentation about their interaction? This is important also to understand autoloading within ractors, since constant references may trigger `require` calls. -- https://bugs.ruby-lang.org/

5 13

[ruby-core:111075] [Ruby master Bug#19161] Cannot compile 3.0.5 or 3.1.3 on Red Hat 7
by werebus (Matt Moretti) 25 Mar '24

25 Mar '24

Issue #19161 has been reported by werebus (Matt Moretti). ---------------------------------------- Bug #19161: Cannot compile 3.0.5 or 3.1.3 on Red Hat 7 https://bugs.ruby-lang.org/issues/19161 * Author: werebus (Matt Moretti) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- When attempting to run `make` on either the 3.0.5 or 3.1.3 release, I get the following error (I included the whole output as it's pretty short): ``` BASERUBY = /opt/ruby/bin/ruby --disable=gems CC = gcc -std=gnu11 LD = ld LDSHARED = gcc -std=gnu11 -shared CFLAGS = -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wimplicit-function-declaration -Wimplicit-int -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable XCFLAGS = -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fno-strict-overflow -fvisibility=hidden -fexcess-precision=standard -DRUBY_EXPORT -fPIE -I. -I.ext/include/x86_64-linux -I./include -I. -I./enc/unicode/13.0.0 CPPFLAGS = DLDFLAGS = -Wl,--compress-debug-sections=zlib -fstack-protector-strong -pie SOLIBS = -lz -lpthread -lrt -lrt -ldl -lcrypt -lm LANG = en_US.UTF-8 LC_ALL = LC_CTYPE = MFLAGS = gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44) Copyright (C) 2015 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. compiling ./main.c compiling dmydln.c compiling miniinit.c In file included from vm_core.h:83:0, from iseq.h:14, from mini_builtin.c:3, from miniinit.c:51: thread_pthread.h:108:43: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘struct’ RUBY_EXTERN RB_THREAD_LOCAL_SPECIFIER struct rb_execution_context_struct *ruby_current_ec; ^ In file included from iseq.h:14:0, from mini_builtin.c:3, from miniinit.c:51: vm_core.h: In function ‘rb_current_execution_context’: vm_core.h:1870:34: error: ‘ruby_current_ec’ undeclared (first use in this function) rb_execution_context_t *ec = ruby_current_ec; ^ vm_core.h:1870:34: note: each undeclared identifier is reported only once for each function it appears in miniinit.c: At top level: cc1: warning: unrecognized command line option "-Wno-tautological-compare" [enabled by default] cc1: warning: unrecognized command line option "-Wno-self-assign" [enabled by default] cc1: warning: unrecognized command line option "-Wno-parentheses-equality" [enabled by default] cc1: warning: unrecognized command line option "-Wno-constant-logical-operand" [enabled by default] cc1: warning: unrecognized command line option "-Wno-cast-function-type" [enabled by default] make: *** [miniinit.o] Error 1 ``` Both Ruby 3.0.4 and 3.1.2 build without error and pass (all but one of) the `make check` tests. I know RHEL 7 is getting to be pretty old; I suspect a factor here are the ancient build tools available to me. But... EOL for Ruby 2.7 comes before the one for RHEL 7, so I'm trying to prioritize. -- https://bugs.ruby-lang.org/

10 14

[ruby-core:111074] [Ruby master Bug#19160] cmp_clamp arguments
by kaiquekandykoga 14 Nov '23

14 Nov '23

Issue #19160 has been reported by kaiquekandykoga (Kaíque Koga). ---------------------------------------- Bug #19160: cmp_clamp arguments https://bugs.ruby-lang.org/issues/19160 * Author: kaiquekandykoga (Kaíque Koga) * Status: Open * Priority: Normal * ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-freebsd13.1] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- If clamp receives min higher than max, it will raise an exception. The message says *min argument must be smaller than max argument* , but min can actually be equal to max too. Patch https://github.com/ruby/ruby/pull/6802. -- https://bugs.ruby-lang.org/

2 1

[ruby-core:111053] [Ruby master Bug#19158] Ruby 3.1.3 installs wrong gemspec for debug gem
by deivid 23 Feb '23

23 Feb '23

Issue #19158 has been reported by deivid (David Rodríguez). ---------------------------------------- Bug #19158: Ruby 3.1.3 installs wrong gemspec for debug gem https://bugs.ruby-lang.org/issues/19158 * Author: deivid (David Rodríguez) * Status: Open * Priority: Normal * ruby -v: ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [arm64-darwin22] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- A pristine installation of Ruby 3.1.3 shows an installed `debug-1.6.3.gemspec` file that claims that debug-1.6.3 has no dependencies. This is incorrect, and causes issues for Bundler as reported at https://github.com/rubygems/rubygems/issues/6082. An issue workaround is to manually reinstall the gem with `gem install debug:1.6.3`. That will reinstall the gem, including a correct gemspec file. This is the file diff before and after reinstalling the gem ```diff --- old.gemspec 2022-11-29 13:54:36 +++ /Users/deivid/.asdf/installs/ruby/3.1.3/lib/ruby/gems/3.1.0/specifications/debug-1.6.3.gemspec 2022-11-29 13:55:25 @@ -24,4 +24,16 @@ s.summary = "Debugging functionality for Ruby".freeze s.installed_by_version = "3.3.26" if s.respond_to? :installed_by_version + + if s.respond_to? :specification_version then + s.specification_version = 4 + end + + if s.respond_to? :add_runtime_dependency then + s.add_runtime_dependency(%q<irb>.freeze, [">= 1.3.6"]) + s.add_runtime_dependency(%q<reline>.freeze, [">= 0.3.1"]) + else + s.add_dependency(%q<irb>.freeze, [">= 1.3.6"]) + s.add_dependency(%q<reline>.freeze, [">= 0.3.1"]) + end end ``` In general, the files installed by ruby-core for bundled gems should be identical to the ones installed by explicit `gem install`. This issue is also present in master and I'm guessing it was introduced by https://github.com/ruby/ruby/commit/a2c66f52f402cb58372e271226f3341065561e53 (backported at https://github.com/ruby/ruby/commit/2d26e45135af8b427d9ccc6d47082c21be8b9c74) -- https://bugs.ruby-lang.org/

3 9

[ruby-core:111022] [Ruby master Bug#19153] Since 2.7.7 CGI::Cookie raises ArgumentError when cookie domains is prefixed with a dot
by cpinto (Celso Pinto) 23 Feb '23

23 Feb '23

Issue #19153 has been reported by cpinto (Celso Pinto). ---------------------------------------- Bug #19153: Since 2.7.7 CGI::Cookie raises ArgumentError when cookie domains is prefixed with a dot https://bugs.ruby-lang.org/issues/19153 * Author: cpinto (Celso Pinto) * Status: Open * Priority: Normal * ruby -v: ruby 2.7.7p221 (2022-11-24 revision 168ec2b1e5) [arm64-darwin22] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- The rspec tests of our Rails app started failing with an ArgumentError after upgrading to 2.7.7. On inspection, the issue seems to be caused by CGI::Cookie.domain=: ``` def domain=(str) if str and ((str = str.b).bytesize > 255 or !DOMAIN_VALUE_RE.match?(str)) raise ArgumentError, "invalid domain: #{str.dump}" end @domain = str end ``` Setting a breakpoint: 0> str => ".example.com" 0> DOMAIN_VALUE_RE => /\A(?<label>(?!-)[-A-Za-z0-9]+(?<!-))(?:\.\g<label>)*\z/ 0> DOMAIN_VALUE_RE.match?(str) => false 0> DOMAIN_VALUE_RE.match?('example.com') => true -- https://bugs.ruby-lang.org/

4 5

[ruby-core:111010] [Ruby master Bug#19150] pack/unpack silently ignores unknown directives
by Eregon (Benoit Daloze) 05 Jan '23

05 Jan '23

Issue #19150 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Bug #19150: pack/unpack silently ignores unknown directives https://bugs.ruby-lang.org/issues/19150 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- But I believe it should be an error instead. Typically when a parser sees a syntax error it should fail not continue silently. For instance `[1].pack('<L')` succeeds and only emits a warning if `$VERBOSE` is true. This behavior caused confusion in https://github.com/oracle/truffleruby/issues/2791 I think it should fail with an `ArgumentError` instead. Extracted from https://bugs.ruby-lang.org/issues/19108#note-3 -- https://bugs.ruby-lang.org/

4 4

[ruby-core:111036] [Ruby master Bug#19156] ObjectSpace.dump_all segfault during string inspection
by mk 02 Dec '22

02 Dec '22

Issue #19156 has been reported by mk (Matthias Käppler). ---------------------------------------- Bug #19156: ObjectSpace.dump_all segfault during string inspection https://bugs.ruby-lang.org/issues/19156 * Author: mk (Matthias Käppler) * Status: Open * Priority: Normal * ruby -v: ruby 3.0.4p208 (2022-04-12 revision 3fa771dded) [x86_64-linux] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- I am working on a feature that would allow our application to capture heap dumps during shutdown for later inspection. These heap dumps are captured via `ObjectSpace.dump_all(output: io)`. While walking the object space, MRI occasionally segfaults while inspect string object in `search_nonascii` of `string.c`: ``` /usr/local/lib/ruby/3.0.0/objspace.rb:87: [BUG] Segmentation fault at 0x00007efee4201000 ruby 3.0.4p208 (2022-04-12 revision 3fa771dded) [x86_64-linux] ... -- Control frame information ----------------------------------------------- c:0053 p:---- s:0312 e:000311 CFUNC :_dump_all c:0052 p:0130 s:0305 e:000304 METHOD /usr/local/lib/ruby/3.0.0/objspace.rb:87 c:0051 p:0023 s:0295 e:000294 METHOD /home/git/gitlab/lib/gitlab/memory/reports/heap_dump.rb:26 ... -- C level backtrace information ------------------------------------------- /usr/local/lib/libruby.so.3.0(rb_print_backtrace+0x11) [0x7efee4ad0c5e] vm_dump.c:758 /usr/local/lib/libruby.so.3.0(rb_vm_bugreport) vm_dump.c:998 /usr/local/lib/libruby.so.3.0(rb_bug_for_fatal_signal+0xf8) [0x7efee48d0b08] error.c:787 /usr/local/lib/libruby.so.3.0(sigsegv+0x55) [0x7efee4a23db5] signal.c:963 /lib/x86_64-linux-gnu/libpthread.so.0(__restore_rt+0x0) [0x7efee4f12140] ../sysdeps/pthread/funlockfile.c:28 /usr/local/lib/libruby.so.3.0(search_nonascii+0x30) [0x7efee4a3ca60] string.c:552 /usr/local/lib/libruby.so.3.0(coderange_scan) string.c:585 /usr/local/lib/libruby.so.3.0(enc_coderange_scan+0x1b) [0x7efee4a3e28a] string.c:709 /usr/local/lib/libruby.so.3.0(rb_enc_str_coderange) string.c:727 /usr/local/lib/ruby/3.0.0/x86_64-linux/objspace.so(is_broken_string+0x8) [0x7efeced9c304] ../../internal/string.h:116 /usr/local/lib/ruby/3.0.0/x86_64-linux/objspace.so(dump_object) objspace_dump.c:388 /usr/local/lib/ruby/3.0.0/x86_64-linux/objspace.so(heap_i+0x39) [0x7efeced9caa9] objspace_dump.c:521 /usr/local/lib/libruby.so.3.0(objspace_each_objects_without_setup+0xaf) [0x7efee48e878f] gc.c:3232 /usr/local/lib/libruby.so.3.0(objspace_each_objects_protected+0x14) [0x7efee48e87c4] gc.c:3242 /usr/local/lib/libruby.so.3.0(rb_ensure+0x12a) [0x7efee48d96aa] eval.c:1162 /usr/local/lib/libruby.so.3.0(objspace_each_objects+0x28) [0x7efee48fb458] gc.c:3310 /usr/local/lib/libruby.so.3.0(rb_objspace_each_objects) gc.c:3298 /usr/local/lib/ruby/3.0.0/x86_64-linux/objspace.so(objspace_dump_all+0x88) [0x7efeced9b068] objspace_dump.c:616 ... ``` Unfortunately I couldn't get my hands on that memory region to see which strings are causing this since this doesn't always happen. I suspect this is also a problem with MRI master since the code looks unchanged from 3.0.4. -- https://bugs.ruby-lang.org/

2 24

[ruby-core:111054] [Ruby master Bug#19159] ObjectSpace segfaults
by matsuda (Akira Matsuda) 01 Dec '22

01 Dec '22

Issue #19159 has been reported by matsuda (Akira Matsuda). ---------------------------------------- Bug #19159: ObjectSpace segfaults https://bugs.ruby-lang.org/issues/19159 * Author: matsuda (Akira Matsuda) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.0dev (2022-11-29T09:23:00Z master 67ae3e9738) +YJIT [arm64-darwin21] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- ``` $ ruby -e 'p ObjectSpace.each_object.to_a' ``` segfaults on my M1MBP as follows: ``` $ ruby -e 'p ObjectSpace.each_object.to_a' -e:1: [BUG] Segmentation fault at 0x0000000000000000 ruby 3.2.0dev (2022-11-29T09:23:00Z master 67ae3e9738) +YJIT [arm64-darwin21] -- 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:0005 p:---- s:0017 e:000016 CFUNC :inspect c:0004 p:---- s:0014 e:000013 CFUNC :inspect c:0003 p:---- s:0011 e:000010 CFUNC :p c:0002 p:0009 s:0006 e:000005 EVAL -e:1 [FINISH] c:0001 p:0000 s:0003 E:0005a0 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- -e:1:in `<main>' -e:1:in `p' -e:1:in `inspect' -e:1:in `inspect' -- Machine register context ------------------------------------------------ x0: 0x0000000000000000 x1: 0x0000000000000004 x2: 0x0000000000000001 x3: 0x0000000104090e94 x4: 0x0000000000000275 x5: 0x0000000000000ad1 x6: 0x0000000000000020 x7: 0x000000016ef18a00 x18: 0x0000000000000000 x19: 0x0000000000000000 x20: 0x0000000000000001 x21: 0x0000000000000004 x22: 0x0000000104090e98 x23: 0x0000000000000001 x24: 0x0000000000000000 x25: 0x0000000000000001 x26: 0x0000000158127f00 x27: 0x00006000032ab4b0 x28: 0x0000000055550083 lr: 0x000000010108a058 fp: 0x000000016ef1a0f0 sp: 0x000000016ef1a0b0 -- C level backtrace information ------------------------------------------- ~/.rbenv/versions/3.2.0-dev/bin/ruby(rb_vm_bugreport+0x2410000000009ac) [0x24100010115a564] ~/.rbenv/versions/3.2.0-dev/bin/ruby(rb_bug_for_fatal_signal) [0x9b16000100f7fe68] ~/.rbenv/versions/3.2.0-dev/bin/ruby(sig_do_nothing) [0x646c0001010b9638] /usr/lib/system/libsystem_platform.dylib(_sigtramp+0x664c000000000038) [0x664c0001a77f34a4] [0x38] -- Other runtime information ----------------------------------------------- * Loaded script: -e * Loaded features: 0 enumerator.so 1 thread.rb 2 fiber.so 3 rational.so 4 complex.so 5 ruby2_keywords.rb 6 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/encdb.bundle 7 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/trans/transdb.bundle 8 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/rbconfig.rb 9 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/compatibility.rb 10 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/defaults.rb 11 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/deprecate.rb 12 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/errors.rb 13 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/unknown_command_spell_checker.rb 14 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/exceptions.rb 15 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/basic_specification.rb 16 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/stub_specification.rb 17 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/platform.rb 18 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/util/list.rb 19 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/version.rb 20 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/requirement.rb 21 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/specification.rb 22 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/util.rb 23 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/dependency.rb 24 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_gem.rb 25 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 26 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/monitor.rb 27 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_require.rb 28 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/core_ext/kernel_warn.rb 29 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems.rb 30 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/rubygems/path_support.rb 31 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/error_highlight/version.rb 32 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/error_highlight/base.rb 33 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/error_highlight/formatter.rb 34 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/error_highlight/core_ext.rb 35 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/error_highlight.rb 36 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/version.rb 37 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/core_ext/name_error.rb 38 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/levenshtein.rb 39 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/jaro_winkler.rb 40 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checker.rb 41 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/name_error_checkers/class_name_checker.rb 42 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb 43 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/name_error_checkers.rb 44 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/method_name_checker.rb 45 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/key_error_checker.rb 46 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/null_checker.rb 47 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/tree_spell_checker.rb 48 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/require_path_checker.rb 49 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/spell_checkers/pattern_key_name_checker.rb 50 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean/formatter.rb 51 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/did_you_mean.rb 52 ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/syntax_suggest/core_ext.rb * Process memory map: 100ee4000-101390000 r-x ~/.rbenv/versions/3.2.0-dev/bin/ruby 101390000-1013ac000 r-- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1013ac000-1013b0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1013b0000-1013c0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1013c0000-1015a8000 r-- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1015a8000-1016a8000 r-- /usr/lib/dyld 1016a8000-1016b0000 rw- /usr/lib/dyld 1016b0000-1016b4000 r-- /usr/lib/dyld 1016b4000-1016b8000 r-- /usr/lib/dyld 1016b8000-1016bc000 rw- /usr/lib/dyld 1016bc000-1016c0000 --- /usr/lib/dyld 1016c0000-1016c8000 rw- /usr/lib/dyld 1016c8000-1016cc000 --- /usr/lib/dyld 1016cc000-1016d0000 --- /usr/lib/dyld 1016d0000-1016d8000 rw- /usr/lib/dyld 1016d8000-1016dc000 --- /usr/lib/dyld 1016dc000-1016e0000 --- /usr/lib/dyld 1016e0000-1016e8000 rw- /usr/lib/dyld 1016e8000-1016ec000 --- /usr/lib/dyld 1016ec000-1016f0000 r-- /usr/lib/dyld 1016f0000-1016f4000 r-- /usr/lib/dyld 1016f4000-1016f8000 rw- /usr/lib/dyld 1016f8000-1016fc000 r-- /usr/lib/dyld 1016fc000-10173c000 rw- /usr/lib/dyld 101740000-101750000 rw- /usr/lib/dyld 10175c000-1017bc000 r-x /usr/lib/dyld 1017bc000-1017d4000 r-- /usr/lib/dyld 1017d4000-1017d8000 rw- /usr/lib/dyld 1017d8000-101810000 r-- /usr/lib/dyld 101810000-101868000 r-x /opt/homebrew/Cellar/gmp/6.2.1_1/lib/libgmp.10.dylib 101868000-10186c000 r-- /opt/homebrew/Cellar/gmp/6.2.1_1/lib/libgmp.10.dylib 10186c000-101870000 rw- /opt/homebrew/Cellar/gmp/6.2.1_1/lib/libgmp.10.dylib 101870000-101880000 r-- /opt/homebrew/Cellar/gmp/6.2.1_1/lib/libgmp.10.dylib 101880000-101884000 r-x ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/encdb.bundle 101884000-101888000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/encdb.bundle 101888000-10188c000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/encdb.bundle 101890000-1018a0000 rw- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/trans/transdb.bundle 1018a0000-1018a4000 r-x ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/trans/transdb.bundle 1018a4000-1018a8000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/trans/transdb.bundle 1018a8000-1018ac000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/enc/trans/transdb.bundle 1018b0000-1018c0000 rw- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 1018c0000-1018c4000 r-x ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 1018c4000-1018c8000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 1018c8000-1018cc000 rw- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 1018cc000-1018d0000 r-- ~/.rbenv/versions/3.2.0-dev/lib/ruby/3.2.0+3/arm64-darwin21/monitor.bundle 1018d0000-1018e0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1018f0000-101900000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 101910000-101920000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 101920000-102920000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102930000-102940000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102950000-102960000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102970000-102980000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102980000-102984000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102984000-102a28000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102a28000-102a2c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102a2c000-102ad0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102ad0000-102ad4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102ad4000-102b78000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102b78000-102b7c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102b7c000-102c20000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102c20000-102c24000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102c24000-102cc8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102cc8000-102ccc000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102ccc000-102d70000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102d70000-102d74000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102d74000-102e18000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102e18000-102e1c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102e1c000-102ec0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102ec0000-102ec4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102ec4000-102f68000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102f68000-102f6c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 102f6c000-103010000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103010000-103014000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103014000-1030b8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1030b8000-1030bc000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1030bc000-103160000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103160000-103164000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103164000-103208000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103208000-10320c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10320c000-1032b0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1032b0000-1032b4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1032b4000-103358000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103358000-10335c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10335c000-103400000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103400000-103404000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103404000-1034a8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1034a8000-1034ac000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1034ac000-103550000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103550000-103554000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103554000-1035f8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1035f8000-1035fc000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1035fc000-1036a0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1036a0000-1036a4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1036a4000-103748000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103748000-10374c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10374c000-1037f0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1037f0000-1037f4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1037f4000-103898000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103898000-10389c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10389c000-103940000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103940000-103944000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103944000-1039e8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1039e8000-1039ec000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1039ec000-103a90000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103a90000-103a94000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103a94000-103b38000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103b38000-103b3c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103b3c000-103be0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103be0000-103be4000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103be4000-103c88000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103c88000-103c8c000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103c8c000-103d30000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103d30000-103d34000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103d34000-103dd8000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103dd8000-103ddc000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103ddc000-103e80000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103e90000-103ea0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103eb0000-103ec0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103ed0000-103ee0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103ef0000-103f00000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103f10000-103f20000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103f30000-103f40000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103f50000-103f60000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103f70000-103f80000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103f90000-103fa0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103fb0000-103fc0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103fd0000-103fe0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 103ff0000-104000000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 104010000-104020000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 104030000-104040000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 104050000-104060000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 104070000-104080000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 104090000-1040a0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1040b0000-1040c0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1040d0000-1040e0000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 1040e0000-1040e4000 r-x ~/.rbenv/versions/3.2.0-dev/bin/ruby 1040e4000-1040e8000 r-x ~/.rbenv/versions/3.2.0-dev/bin/ruby 1040e8000-10c0e0000 --- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10c0f0000-10c100000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10c110000-10c120000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10c130000-10c140000 rw- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10c140000-10c7f4000 r-- ~/.rbenv/versions/3.2.0-dev/bin/ruby 10c7f4000-10cea8000 r-- ~/.rbenv/versions/3.2.0-dev/bin/ruby 138000000-138800000 rw- 138800000-139000000 rw- 139000000-139800000 rw- 139800000-13a000000 rw- 13a000000-13a800000 rw- 13a800000-13b000000 rw- 13b000000-13b800000 rw- 13b800000-13c000000 rw- 13c000000-13c800000 rw- 13c800000-13d000000 rw- 13d000000-13d800000 rw- 13d800000-13e000000 rw- 13e000000-13e800000 rw- 13e800000-13f000000 rw- 13f000000-13f800000 rw- 13f800000-140000000 rw- 146e00000-146f00000 rw- 146f00000-147000000 rw- 147000000-147800000 rw- 147800000-148000000 rw- 148000000-148800000 rw- 148800000-149000000 rw- 149000000-149800000 rw- 149800000-14a000000 rw- 14a000000-14a800000 rw- 14a800000-14b000000 rw- 14b000000-14b800000 rw- 14b800000-14c000000 rw- 14c000000-14c800000 rw- 14c800000-14d000000 rw- 14d000000-14d800000 rw- 14d800000-14e000000 rw- 14e000000-14e800000 rw- 14e800000-14f000000 rw- 14f000000-14f800000 rw- 14f800000-150000000 rw- 156e00000-156f00000 rw- 156f00000-157000000 rw- 157000000-157800000 rw- 157800000-157804000 rw- 158000000-158800000 rw- 158800000-159000000 rw- 159000000-159800000 rw- 159800000-15a000000 rw- 15a000000-15a800000 rw- 15a800000-15b000000 rw- 15b000000-15b800000 rw- 15b800000-15c000000 rw- 15c000000-15c800000 rw- 15c800000-15d000000 rw- 15d000000-15d800000 rw- 15d800000-15e000000 rw- 15e000000-15e800000 rw- 15e800000-15f000000 rw- 15f000000-15f800000 rw- 15f800000-160000000 rw- 160000000-162000000 rw- 162000000-162800000 rw- 16af1c000-16e720000 --- 16e720000-16ef1c000 rw- 16ef1c000-16ef20000 --- 16ef20000-16efa8000 rw- 180000000-1fc000000 r-- 1fc000000-1fd9d8000 r-- 1fd9d8000-1fd9fc000 rw- 1fd9fc000-1fe000000 rw- 1fe000000-200000000 r-- 200000000-2001e8000 r-- 2001e8000-2018dc000 rw- 2018dc000-204c64000 r-- 204c64000-206000000 r-- 206000000-236000000 r-- 236000000-236a10000 r-- 236a10000-2377f4000 rw- 2377f4000-238ac0000 r-- 238ac0000-23a000000 r-- 23a000000-280000000 r-- fc0000000-1000000000 --- 1000000000-7000000000 --- 600000000000-600008000000 rw- 600008000000-600010000000 rw- 600010000000-600018000000 rw- 600018000000-600020000000 rw- [IMPORTANT] Don't forget to include the Crash Report log file under DiagnosticReports directory in bug reports. ``` -- https://bugs.ruby-lang.org/

4 5

[ruby-core:111098] [Ruby master Feature#19000] Data: Add "Copy with changes method" [Follow-on to #16122 Data: simple immutable value object]
by RubyBugs (A Nonymous) 30 Nov '22

30 Nov '22

Issue #19000 has been updated by RubyBugs (A Nonymous). For comparison, you can plug in the following example code for a faster implementation of `#with` and it should work the same: ```ruby Point = Data.define(:x, :y) do # Example only, too slow. Real implementation should eliminate allocations. # def with(**args) # raise ArgumentError unless args.keys.all? { |k| members.include? k } # self.class.new(**(to_h.merge(args))) # end # A trick to avoid `nil` for defaults so that `nil` can be valid DEFAULT = class.new.new.freeze # An example of a faster implementation that could inspire auto-generation def with(x: DEFAULT, y: DEFAULT) self.class.new( x: x.equal?(DEFAULT) ? self.x : x), y: y.equal?(DEFAULT) ? self.y : y), ) end end ``` ---------------------------------------- Feature #19000: Data: Add "Copy with changes method" [Follow-on to #16122 Data: simple immutable value object] https://bugs.ruby-lang.org/issues/19000#change-100364 * Author: RubyBugs (A Nonymous) * Status: Open * Priority: Normal ---------------------------------------- *As requested: extracted a follow-up to #16122 Data: simple immutable value object from [this comment](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/109815)* # Proposal: Add a "Copy with changes" method to Data Assume the proposed `Data.define` exists. Seeing examples from the [[Values gem]](https://github.com/ms-ati/Values): ```ruby # A new class Point = Data.def(:x, :y) # An immutable instance Origin = Point.with(x: 0, y: 0) # Q: How do we make copies that change 1 or more values? right = Origin.with(x: 1.0) up = Origin.with(y: 1.0) up_and_right = right.with(y: up.y) # In loops movements = [ { x: +0.5 }, { x: +0.5 }, { y: -1.0 }, { x: +0.5 }, ] # position = Point(x: 1.5, y: -1.0) position = movements.inject(Origin) { |p, move| p.with(**move) } ``` ## Proposed detail: Call this method: `#with` ```ruby Money = Data.define(:amount, :currency) account = Money.new(amount: 100, currency: 'USD') transactions = [+10, -5, +15] account = transactions.inject(account) { |a, t| a.with(amount: a.amount + t) } #=> Money(amount: 120, currency: "USD") ``` ## Why add this "Copy with changes" method to the Data simple immutable value class? Called on an instance, it returns a new instance with only the provided parameters changed. This API affordance is now **widely adopted across many languages** for its usefulness. Why is it so useful? Because copying immutable value object instances, with 1 or more discrete changes to specific fields, is the proper and ubiquitous pattern that takes the place of mutation when working with immutable value objects. **Other languages** C# Records: “immutable record structs — Non-destructive mutation” — is called `with { ... }` https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-t… Scala Case Classes — is called `#copy` https://docs.scala-lang.org/tour/case-classes.html Java 14+ Records — Brian Goetz at Oracle is working on adding a with copy constructor inspired by C# above as we speak, likely to be called `#with` https://mail.openjdk.org/pipermail/amber-spec-experts/2022-June/003461.html Rust “Struct Update Syntax” via `..` syntax in constructor https://doc.rust-lang.org/book/ch05-01-defining-structs.html#creating-insta… ## Alternatives Without a copy-with-changes method, one must construct entirely new instances using the constructor. This can either be (a) fully spelled out as boilerplate code, or (b) use a symmetrical `#to_h` to feed the keyword-args constructor. **(a) Boilerplate using constructor** ```ruby Point = Data.define(:x, :y, :z) Origin = Point.new(x: 0.0, y: 0.0, z: 0.0) change = { z: -1.5 } # Have to use full constructor -- does this even work? point = Point.new(x: Origin.x, y: Origin.y, **change) ``` **(b) Using a separately proposed `#to_h` method and constructor symmetry** ```ruby Point = Data.define(:x, :y, :z) Origin = Point.new(x: 0.0, y: 0.0, z: 0.0) change = { z: -1.5 } # Have to use full constructor -- does this even work? point = Point.new(**(Origin.to_h.merge(change))) ``` Notice that the above are not ergonomic -- leading so many of our peer language communities to adopt the `#with` method to copy an instance with discrete changes. -- https://bugs.ruby-lang.org/

1 0

[ruby-core:111097] [Ruby master Feature#19000] Data: Add "Copy with changes method" [Follow-on to #16122 Data: simple immutable value object]
by RubyBugs (A Nonymous) 30 Nov '22

30 Nov '22

Issue #19000 has been updated by RubyBugs (A Nonymous). mame (Yusuke Endoh) wrote in #note-17: > @RubyBugs Please check my comment https://bugs.ruby-lang.org/issues/19000#note-13 . A wrong motivation example raises the suspicion that this API is actually confusing to users. Quite right @mame, thank you for catching that! I provided two examples. The first example is intended to use the previous values in creating the next values, and that part was broken. How is this? ```ruby ## # Example of proposed Data#with # # To try this out: # # ruby-install ruby-3.2.0-preview3 # ## Point = Data.define(:x, :y) do # Example only, too slow. Real implementation should eliminate allocations. def with(**args) raise ArgumentError unless args.keys.all? { |k| members.include? k } self.class.new(**(to_h.merge(args))) end end Origin = Point.new(x: 0, y: 0) # Q: How do we make copies that change 1 or more values? right = Origin.with(x: 1.0) up = Origin.with(y: 1.0) up_and_right = right.with(y: up.y) begin Origin.with(x: 1, z: 0) rescue ArgumentError puts "#with(z: 0) raised ArgumentError as expected" end # In loops movements = [ [ :x, +0.5 ], [ :x, +0.5 ], [ :y, -1.0 ], [ :x, +0.5 ], ] position = movements.inject(Origin) do |p, (field, delta)| p.with(field => p.to_h[field] + delta) end # position = Point(x: 1.5, y: -1.0) ``` ---------------------------------------- Feature #19000: Data: Add "Copy with changes method" [Follow-on to #16122 Data: simple immutable value object] https://bugs.ruby-lang.org/issues/19000#change-100363 * Author: RubyBugs (A Nonymous) * Status: Open * Priority: Normal ---------------------------------------- *As requested: extracted a follow-up to #16122 Data: simple immutable value object from [this comment](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/109815)* # Proposal: Add a "Copy with changes" method to Data Assume the proposed `Data.define` exists. Seeing examples from the [[Values gem]](https://github.com/ms-ati/Values): ```ruby # A new class Point = Data.def(:x, :y) # An immutable instance Origin = Point.with(x: 0, y: 0) # Q: How do we make copies that change 1 or more values? right = Origin.with(x: 1.0) up = Origin.with(y: 1.0) up_and_right = right.with(y: up.y) # In loops movements = [ { x: +0.5 }, { x: +0.5 }, { y: -1.0 }, { x: +0.5 }, ] # position = Point(x: 1.5, y: -1.0) position = movements.inject(Origin) { |p, move| p.with(**move) } ``` ## Proposed detail: Call this method: `#with` ```ruby Money = Data.define(:amount, :currency) account = Money.new(amount: 100, currency: 'USD') transactions = [+10, -5, +15] account = transactions.inject(account) { |a, t| a.with(amount: a.amount + t) } #=> Money(amount: 120, currency: "USD") ``` ## Why add this "Copy with changes" method to the Data simple immutable value class? Called on an instance, it returns a new instance with only the provided parameters changed. This API affordance is now **widely adopted across many languages** for its usefulness. Why is it so useful? Because copying immutable value object instances, with 1 or more discrete changes to specific fields, is the proper and ubiquitous pattern that takes the place of mutation when working with immutable value objects. **Other languages** C# Records: “immutable record structs — Non-destructive mutation” — is called `with { ... }` https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-t… Scala Case Classes — is called `#copy` https://docs.scala-lang.org/tour/case-classes.html Java 14+ Records — Brian Goetz at Oracle is working on adding a with copy constructor inspired by C# above as we speak, likely to be called `#with` https://mail.openjdk.org/pipermail/amber-spec-experts/2022-June/003461.html Rust “Struct Update Syntax” via `..` syntax in constructor https://doc.rust-lang.org/book/ch05-01-defining-structs.html#creating-insta… ## Alternatives Without a copy-with-changes method, one must construct entirely new instances using the constructor. This can either be (a) fully spelled out as boilerplate code, or (b) use a symmetrical `#to_h` to feed the keyword-args constructor. **(a) Boilerplate using constructor** ```ruby Point = Data.define(:x, :y, :z) Origin = Point.new(x: 0.0, y: 0.0, z: 0.0) change = { z: -1.5 } # Have to use full constructor -- does this even work? point = Point.new(x: Origin.x, y: Origin.y, **change) ``` **(b) Using a separately proposed `#to_h` method and constructor symmetry** ```ruby Point = Data.define(:x, :y, :z) Origin = Point.new(x: 0.0, y: 0.0, z: 0.0) change = { z: -1.5 } # Have to use full constructor -- does this even work? point = Point.new(**(Origin.to_h.merge(change))) ``` Notice that the above are not ergonomic -- leading so many of our peer language communities to adopt the `#with` method to copy an instance with discrete changes. -- https://bugs.ruby-lang.org/

1 0