May 2023 - ruby-core - ml.ruby-lang.org

[ruby-core:112119] [Ruby master Bug#19392] Endless method vs and/or

by zverok (Victor Shepelev)

Issue #19392 has been reported by zverok (Victor Shepelev). ---------------------------------------- Bug #19392: Endless method vs and/or https://bugs.ruby-lang.org/issues/19392 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal * Backport: 2.7: DONTNEED, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- [Discovered](https://twitter.com/lucianghinda/status/1617783952353406977) by Lucian Ghinda: ```ruby def test = puts("foo") and puts("bar") # prints "bar" immediately test # prints "foo" ``` It seems that it is a parser error, right?.. ```ruby RubyVM::AbstractSyntaxTree.parse('def test = puts("foo") and puts("bar")') # => # (SCOPE@1:0-1:38 # tbl: [] # args: nil # body: # (AND@1:0-1:38 # (DEFN@1:0-1:22 # mid: :test # body: # (SCOPE@1:0-1:22 # tbl: [] # args: # (ARGS@1:0-1:8 pre_num: 0 pre_init: nil opt: nil first_post: nil post_num: 0 post_init: nil rest: nil kw: nil kwrest: nil block: nil) # body: (FCALL@1:11-1:22 :puts (LIST@1:16-1:21 (STR@1:16-1:21 "foo") nil)))) # (FCALL@1:27-1:38 :puts (LIST@1:32-1:37 (STR@1:32-1:37 "bar") nil)))) ``` E.g. it is parsed as ```ruby (def test = puts("foo")) and (puts("bar")) ``` ...which is hardly intentional or have any practical use. The rightly parsed code in this case _can_ have practical use, like ```ruby def write(data) = File.write(@filename, data) == data.size or raise "Something went wrong" ``` -- https://bugs.ruby-lang.org/

6 days, 7 hours

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[ruby-core:113180] [Ruby master Feature#19588] Allow Comparable#clamp(min, max) to accept nil as a specification

by kyanagi (Kouhei Yanagita)

Issue #19588 has been reported by kyanagi (Kouhei Yanagita). ---------------------------------------- Feature #19588: Allow Comparable#clamp(min, max) to accept nil as a specification https://bugs.ruby-lang.org/issues/19588 * Author: kyanagi (Kouhei Yanagita) * Status: Open * Priority: Normal ---------------------------------------- `Comparable#clamp(min, max)` (with two arguments) accepts `nil`. This behaves the same as beginless/endless Range. ~~~ruby 5.clamp(nil, 0) # => 0 5.clamp(10, nil) # => 10 5.clamp(..0) # => 0 5.clamp(10..) # => 10 ~~~ This behavior is not documented. Presumably, this was not introduced intentionally. The old Rubies did not accept accept a `Range` argument. In Ruby 2.7, accepting `Range` as an argument was introduced. At that time, the approach of passing `nil` as a two-argument method was also discussed but not adopted, and using Range was chosen instead. https://bugs.ruby-lang.org/issues/14784 However, in Ruby 3.0, the behavior of `clamp` has changed to accept `nil`. This change is not documented in the NEWS or the documentation for `clamp`, and I believe that it was not an intentional change. ~~~ % docker run -it --rm rubylang/all-ruby env ALL_RUBY_SINCE=ruby-2.4.0 ./all-ruby -e "p 5.clamp(0, nil)" ruby-2.4.0 -e:1:in `clamp': comparison of Integer with nil failed (ArgumentError) from -e:1:in `<main>' exit 1 ... ruby-2.7.8 -e:1:in `clamp': comparison of Integer with nil failed (ArgumentError) from -e:1:in `<main>' exit 1 ruby-3.0.0-preview1 5 ... ruby-3.2.2 5 ~~~ It seems that https://github.com/ruby/ruby/commit/a93da4970be44a473b7b42e7516eb2663dece2c3 brought about this change. How about making the current behavior a specification? It has been three years since the behavior changed, and I don't see much point in prohibiting `nil` now. -- https://bugs.ruby-lang.org/

6 days, 20 hours

5
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[ruby-core:111988] [Ruby master Feature#19370] Anonymous parameters for blocks?

by zverok (Victor Shepelev)

Issue #19370 has been reported by zverok (Victor Shepelev). ---------------------------------------- Feature #19370: Anonymous parameters for blocks? https://bugs.ruby-lang.org/issues/19370 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal ---------------------------------------- Just to clarify: are anonymous parameters delegation is planned to support in blocks? It would be a nice addition, if it is possible to implement: ```ruby # data in form [request method, URL, params]: [ [:get, 'https://google.com', {q: 'Ruby'}, {'User-Argent': 'Google-Chrome'}], [:post, 'https://gist.github.com', 'body'], # ... ].each { |method, *| request(method.to_s.upcase, *) } ``` ...and at the very least, consistent with what the method definition can have. If they are NOT planned to be implemented, I believe that at least error messages should be made much clearer, because currently, this would happen while running the code above: > no anonymous rest parameter (SyntaxError) I understand the reason (the `request` clause doesn't "see" anonymous parameter of the **block**, and claims that current **method** doesn't have them), but it looks honestly confusing and inconsistent. -- https://bugs.ruby-lang.org/

1 week, 3 days

5
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[ruby-core:112262] [Ruby master Feature#19422] Make `--enabled-shared` mandatory on macOS

by nobu (Nobuyoshi Nakada)

Issue #19422 has been reported by nobu (Nobuyoshi Nakada). ---------------------------------------- Feature #19422: Make `--enabled-shared` mandatory on macOS https://bugs.ruby-lang.org/issues/19422 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Priority: Normal ---------------------------------------- From the troubles around linker on macOS, I propose `--enable-shared` option mandatory on macOS. This patch enables the option by default, and abort if `--disable-shared` option is given explicitly. ```diff diff --git i/configure.ac w/configure.ac index 7db2ab5257c..923ac7d1199 100644 --- i/configure.ac +++ w/configure.ac @@ -504,6 +504,11 @@ AS_CASE(["$target_os"], rb_cv_binary_elf=no : ${enable_shared=yes} ], +[darwin*], [ + AS_IF([test "${enable_shared=yes}" = no], [ + AC_MSG_ERROR([--disable-shared is not supported on this platform]) + ]) +], [hiuxmpp*], [AC_DEFINE(__HIUX_MPP__)]) # by TOYODA Eizi <toyoda(a)npd.kishou.go.jp> AC_PROG_LN_S @@ -3055,14 +3060,7 @@ AC_SUBST(EXTOBJS) : ${LDFLAGS=""} : ${LIBPATHENV=DYLD_FALLBACK_LIBRARY_PATH} : ${PRELOADENV=DYLD_INSERT_LIBRARIES} - AS_IF([test x"$enable_shared" = xyes], [ - # Resolve symbols from libruby.dylib when --enable-shared - EXTDLDFLAGS='$(LIBRUBYARG_SHARED)' - ], [test "x$EXTSTATIC" = x], [ - # When building exts as bundles, a mach-o bundle needs to know its loader - # program to bind symbols from the ruby executable - EXTDLDFLAGS="-bundle_loader '\$(BUILTRUBY)'" - ]) + EXTDLDFLAGS='$(LIBRUBYARG_SHARED)' rb_cv_dlopen=yes], [aix*], [ : ${LDSHARED='$(CC)'} AS_IF([test "$GCC" = yes], [ @@ -3356,10 +3354,6 @@ AS_IF([test x"$cross_compiling" = xyes], [ AC_SUBST(XRUBY_RUBYLIBDIR) AC_SUBST(XRUBY_RUBYHDRDIR) PREP='$(arch)-fake.rb' - AS_CASE(["$enable_shared:$EXTSTATIC:$target_os"], [no::darwin*], [ - # darwin target requires miniruby for linking ext bundles - PREP="$PREP"' miniruby$(EXEEXT)' - ]) RUNRUBY_COMMAND='$(MINIRUBY) -I`cd $(srcdir)/lib; pwd`' RUNRUBY='$(RUNRUBY_COMMAND)' XRUBY='$(MINIRUBY)' ``` -- https://bugs.ruby-lang.org/

2 weeks, 1 day

2
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[ruby-core:111342] [Ruby master Bug#19246] Rebuilding the loaded feature index much slower in Ruby 3.1

by thomthom (Thomas Thomassen)

Issue #19246 has been reported by thomthom (Thomas Thomassen). ---------------------------------------- Bug #19246: Rebuilding the loaded feature index much slower in Ruby 3.1 https://bugs.ruby-lang.org/issues/19246 * Author: thomthom (Thomas Thomassen) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- Some background to this issue: (This is a case that is unconventional usage of Ruby, but I hope you bear with me.) We ship the Ruby interpreter with our desktop applications for plugin support in our application (SketchUp). One feature we have had since, at least 2006 (maybe earlier-hard to track history beyond that) is that we had a custom alternate `require` method: `Sketchup.require`. This allows the users of our API to load encrypted Ruby files. This originally used `rb_provide` to add the path to the encrypted file into the list of loaded feature. However, somewhere between Ruby 2.2 and 2.5 there was some string optimisations made and the function `rb_provide` would not use a copy of the string passed to it. Instead it just held on to a pointer reference. In our case that string came from user-land, being passed in from `Sketchup.require` and would eventually be garbage collected and cause access violation crashes. To work around that we changed our custom `Sketchup.require` to push to `$LOADED_FEATURES` directly. There was a small penalty to the index being rebuilt after that, but it was negligible. Recently we tried to upgrade the Ruby interpreter in our application from 2.7 to 3.1 and found a major performance reduction when using our `Sketchup.require. As in, a plugin that would load in half a second would now spend 30 seconds. From https://bugs.ruby-lang.org/issues/18452 it sounds like there is _some_ expected extra penalty due to changes in how the index is built. But should it really be this much? Example minimal repro to simulate the issue: ``` # frozen_string_literal: true require 'benchmark' iterations = 200 foo_files = iterations.times.map { |i| "#{__dir__}/tmp/foo-#{i}.rb" } foo_files.each { |f| File.write(f, "") } bar_files = iterations.times.map { |i| "#{__dir__}/tmp/bar-#{i}.rb" } bar_files.each { |f| File.write(f, "") } biz_files = iterations.times.map { |i| "#{__dir__}/tmp/biz-#{i}.rb" } biz_files.each { |f| File.write(f, "") } Benchmark.bm do |x| x.report('normal') { foo_files.each { |file| require file } } x.report('loaded_features') { foo_files.each { |file| require file $LOADED_FEATURES << "#{file}-fake.rb" } } x.report('normal again') { biz_files.each { |file| require file } } end ``` ``` C:\Users\Thomas\SourceTree\ruby-perf>ruby27.bat ruby 2.7.4p191 (2021-07-07 revision a21a3b7d23) [x64-mingw32] C:\Users\Thomas\SourceTree\ruby-perf>ruby test-require.rb user system total real normal 0.000000 0.031000 0.031000 ( 0.078483) loaded_features 0.015000 0.000000 0.015000 ( 0.038759) normal again 0.016000 0.032000 0.048000 ( 0.076940) ``` ``` C:\Users\Thomas\SourceTree\ruby-perf>ruby30.bat ruby 2.7.4p191 (2021-07-07 revision a21a3b7d23) [x64-mingw32] C:\Users\Thomas\SourceTree\ruby-perf>ruby test-require.rb user system total real normal 0.000000 0.031000 0.031000 ( 0.074733) loaded_features 0.032000 0.000000 0.032000 ( 0.038898) normal again 0.000000 0.047000 0.047000 ( 0.076343) ``` ``` C:\Users\Thomas\SourceTree\ruby-perf>ruby31.bat ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x64-mingw-ucrt] C:\Users\Thomas\SourceTree\ruby-perf>ruby test-require.rb user system total real normal 0.016000 0.031000 0.047000 ( 0.132633) loaded_features 1.969000 11.500000 13.469000 ( 18.395761) normal again 0.031000 0.125000 0.156000 ( 0.249130) ``` Right now we're exploring options to deal with this. Because the performance degradation is a blocker for us upgrading. We also have 16 years of plugins created by third party developer that makes it impossible for us to drop this feature. Some options as-is, none of which are ideal: 1. We revert to using `rb_provide` but ensure the string passed in is not owned by Ruby, instead building a list of strings that we keep around for the duration of the application process. The problem is that some of our plugin developers have on occasion released plugins that will touch `$LOADED_FEATURES`, and if such a plugin is installed on a user machine it might cause the application to become unresponsive for minutes. The other non-ideal issue with using `rb_provide` is that we're also using that in ways it wasn't really intended (from that I understand). And it's not an official API? 2. We create a separate way for our `Sketchup.require` to keep track of it's loaded features, but then that would diverge even more from the behaviour of `require`. Replicating `require` functionality is not trivial and would be prone to subtle errors and possible diverge. It also doesn't address our issue that there is code out there in existing plugins that touches `$LOADED_FEATURES`. (And it's not something we can just ask people to clean up. From previous experience old versions stick around for a long time and is very hard to purge from circulation.) I have two questions for the Ruby mantainers: 1. Would it be reasonable to see an API for adding/removing/checking `$LOADED_FEATURE` that would allow for a more ideal implementation of a custom `require` functionality? 2. Is the performance difference in rebuilding the loaded feature index really expected to be as high as what we're seeing? An increase of nearly 100 times? Is there something there that might be addressed to make the rebuild to be less expensive against? (This would really help to address our challenges with third party plugins occasionally touching the global.) -- https://bugs.ruby-lang.org/

2 weeks, 3 days

8
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[ruby-core:111074] [Ruby master Bug#19160] cmp_clamp arguments

by kaiquekandykoga

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/

3 weeks, 2 days

2
1
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[ruby-core:113107] [Ruby master Bug#19576] Backport request: Gemfile.lock resolving is broken with bundler shipped with Ruby 3.1.4

by jprokop (Jarek Prokop)

Issue #19576 has been reported by jprokop (Jarek Prokop). ---------------------------------------- Bug #19576: Backport request: Gemfile.lock resolving is broken with bundler shipped with Ruby 3.1.4 https://bugs.ruby-lang.org/issues/19576 * Author: jprokop (Jarek Prokop) * Status: Open * Priority: Normal * ruby -v: ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- This is a backport request for bundler, that regressed in 2.3.36 in a specific situation. Newer and older bundler versions that ship with Ruby are not problematic, only the version that ships with Ruby version >= 3.1.3. A few weeks ago, we discovered a bug in resolving in bundler shipped with Ruby 3.1.3 and 3.1.4: Bundler version: ``` $ bundler --version Bundler version 2.3.26 ``` Affected rubies `ruby -v`: First: ``` $ ruby -v ruby 3.1.4p223 (2023-03-30 revision 957bb7cb81) [x86_64-linux] ``` Second: ``` $ruby -v ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux] ``` Initial bug report with reproducer and more in-depth description can be found here: https://github.com/sclorg/s2i-ruby-container/issues/469 Using the following Gemfile for a rails app: https://github.com/sclorg/rails-ex/blob/67b7a61eae9efa1088ff3f634ae316e1022… bundler locks up in trying to resolve Nokogiri for Ruby 3.1, but keeps failing because it keeps using incompatible built binary gem instead of falling back to installing and building the binary extension of Nokogiri locally. We craft this Gemfile to be usable from Ruby 2.5 up to Ruby 3.1, as the app is used mainly for testing. I have created a patch to fix the situation, see the attached files. There are 2 of them, one contains the fix and the other one contains the test from the rubygems repo PR#6225. full commit available here: https://src.fedoraproject.org/fork/jackorp/rpms/ruby/c/5ef600a8f40b76de5636… The patches are created from the following upstream changes in bundler: https://github.com/rubygems/rubygems/pull/6225 and adapted: https://github.com/rubygems/rubygems/commit/7b64c64262a7a980c0eb23b96ea56cf… for the PR#6225. With the fix applied I no longer have issues doing `bundle install` with our Gemfile.lock. ---Files-------------------------------- rubygem-bundler-2.3.26-Tests-from-bundler-PR-6225.patch (1.82 KB) rubygem-bundler-2.3.26-Provide-fix-for-bundler-Gemfile-resolving-regression.patch (5.21 KB) -- https://bugs.ruby-lang.org/

3 weeks, 5 days

5
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[ruby-core:111739] [Ruby master Feature#19324] Enumerator.product => Enumerable#product

by zverok (Victor Shepelev)

Issue #19324 has been reported by zverok (Victor Shepelev). ---------------------------------------- Feature #19324: Enumerator.product => Enumerable#product https://bugs.ruby-lang.org/issues/19324 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal ---------------------------------------- I know it might be too late after introducing a feature and releasing a version, but I find `Enumerator.product` quite confusing, and can't find any justification in #18685. **Problem 1: It is `Array#product` but `Enumerator.product`** ```ruby [1, 2].product([4, 5]) # => [[1, 4], [1, 5], [2, 4], [2, 5]] # Usually, when we add methods to Enumerable/Enumerator which # already array had before, it is symmetric, say... [1, nil, 2, 3].compact #=> [1, 2, 3] [1, nil, 2, 3].lazy.compact.first(2) #=> [1, 2] # But not in this case: [1, 2].lazy.product([4, 5]).first(2) # undefined method `product' for #<Enumerator::Lazy: [1, 2]> (NoMethodError) # Because you "just" need to change it to: Enumerator.product([1, 2].lazy, [4, 5]).first(2) # => [[1, 4], [1, 5]] ``` No other method was "promoted" from Array this way And in general, I believe core methods tend to belong to the first object in the expression and not be free module methods, Elixir style. **Problem 2: It is one letter different from `Enumerator.produce`** I understand I might be biased here (as a person who proposed `produce`), and that method is not as popular (yet?) as I hoped, but still, two methods that do completely different things and differ by one letter, both being somewhat vague verbs (so it is easy to confuse them unless you did a lot of math and "product" is firmly set for set product in your head). I believe that EITHER of two problems would be concerning enough, but the combination of them seems to be a strong enough argument to make the change?.. (Maybe with graceful deprecation of module method in one next version, but, considering the Ruby 3.2 is just released, maybe vice versa, fix the problem in the next minor release?..) -- https://bugs.ruby-lang.org/

4 weeks, 1 day

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[ruby-core:111953] [Ruby master Bug#19362] #dup on Proc doesn't call initialize_dup

by zverok (Victor Shepelev)

Issue #19362 has been reported by zverok (Victor Shepelev). ---------------------------------------- Bug #19362: #dup on Proc doesn't call initialize_dup https://bugs.ruby-lang.org/issues/19362 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- In #17545, `#dup` had changed to create an instance of the subclass. It, though, doesn't invoke `initialize_dup` of the subclass, unlike other standard classes. ```ruby class MyAry < Array def initialize_dup(...) p(self.class, ...) super end end class MyString < String def initialize_dup(...) p(self.class, ...) super end end class MyProc < Proc def initialize_dup(...) p(self.class, ...) super end end MyString.new('test').dup # prints MyString, "test" MyAry.new(['test']).dup # prints MyAry, ["test"] MyProc.new { 'test' }.dup # doesn't print anything ``` This makes the change in #17545 useless: while inheriting from core classes is indeed marginal, one of author's intention might be carrying additional information with the Proc instance, and bypassing `#initialize_dup` makes it impossible to maintain this information. It seems that actually `#initialize_dup` is also invoked on the core classes themselves, but ignored on `Proc`. ```ruby class Array def initialize_dup(...) p(self.class, ...) super end end class String def initialize_dup(...) p(self.class, ...) super end end class Proc def initialize_dup(...) p(self.class, ...) super end end 'test'.dup # prints String, "test" ['test'].dup # prints Array, ["test"] Proc.new { 'test' }.dup # doesn't print anything ``` Which is an even more marginal problem but still an inconsistency. -- https://bugs.ruby-lang.org/

1 month, 1 week

3
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[ruby-core:112944] [Ruby master Feature#19541] Proposal: Generate frame unwinding info for YJIT code

by kjtsanaktsidis (KJ Tsanaktsidis)

Issue #19541 has been reported by kjtsanaktsidis (KJ Tsanaktsidis). ---------------------------------------- Feature #19541: Proposal: Generate frame unwinding info for YJIT code https://bugs.ruby-lang.org/issues/19541 * Author: kjtsanaktsidis (KJ Tsanaktsidis) * Status: Open * Priority: Normal ---------------------------------------- ## What is being propsed? Currently, Ruby crashes with yjit generated code on the stack, `rb_print_backtrace()` is unable to actually show any frames underneath the yjit code. For example, if you send SIGSEGV to a Ruby process running yjit, this is what you see: ``` /ruby/miniruby(rb_print_backtrace+0xc) [0xaaaad0276884] /ruby/vm_dump.c:785 /ruby/miniruby(rb_vm_bugreport) /ruby/vm_dump.c:1093 /ruby/miniruby(rb_bug_for_fatal_signal+0xd0) [0xaaaad0075580] /ruby/error.c:813 /ruby/miniruby(sigsegv+0x5c) [0xaaaad01bedac] /ruby/signal.c:919 linux-vdso.so.1(__kernel_rt_sigreturn+0x0) [0xffff91a3e8bc] /ruby/miniruby(map<(usize, yjit::backend::ir::Insn), (usize, yjit::backend::ir::Insn), yjit::backend::ir::{impl#17}::next_mapped::{closure_env#0}>+0x8c) [0xaaaad03b8b00] /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/option.rs:929 /ruby/miniruby(next_mapped+0x3c) [0xaaaad0291dc0] src/backend/ir.rs:1225 /ruby/miniruby(arm64_split+0x114) [0xaaaad0287744] src/backend/arm64/mod.rs:359 /ruby/miniruby(compile_with_regs+0x80) [0xaaaad028bf84] src/backend/arm64/mod.rs:1106 /ruby/miniruby(compile+0xc4) [0xaaaad0291ae0] src/backend/ir.rs:1158 /ruby/miniruby(gen_single_block+0xe44) [0xaaaad02b1f88] src/codegen.rs:854 /ruby/miniruby(gen_block_series_body+0x9c) [0xaaaad03b0250] src/core.rs:1698 /ruby/miniruby(gen_block_series+0x50) [0xaaaad03b0100] src/core.rs:1676 /ruby/miniruby(branch_stub_hit_body+0x80c) [0xaaaad03b1f68] src/core.rs:2021 /ruby/miniruby({closure#0}+0x28) [0xaaaad02eb86c] src/core.rs:1924 /ruby/miniruby(do_call<yjit::core::branch_stub_hit::{closure_env#0}, *const u8>+0x98) [0xaaaad035ba3c] /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:492 [0xaaaad035c9b4] ``` (n.b. - I compiled Ruby with `-fasynchronous-unwind-tables –rdynamic –g` in cflags to make sure gcc generates appropriate unwind info & keeps the symbol tables). Likewise, if you attach gdb to a Ruby process with yjit enabled, gdb can't show thread backtraces through yjit-generated code either. My proposal is that YJIT generate sufficient unwinding and debug information on all platforms to allow both `rb_print_backtrace()` and the platform's debugger (gdb/lldb/WinDbg) to show: * Full stack traces all the way back to `main`. That is, it should be possible to see frames _underneath_ `[0xaaaad035c9b4]` from the backtrace above. * Names for the dynamically generated yjit blocks (e.g. instead of `[0xaaaad035c9b4]`, we should see something like `yjit$$name_of_ruby_method`, where `name_of_ruby_method` is the `label` for the iseq this is JIT'd code for). ## Motivation I have a few motivations for wanting this. Firstly, I feel this functionality is independently useful. When Ruby crashes, the more information we can get, the more likely we are to find the root cause. Likewise, the same principle applies to debugging with gdb - you can get a fuller understanding of what the process is doing if you see the whole stack. I have often found attaching gdb to the Ruby interpreter helps in understanding problems in Ruby code or C extensions and is something I do relatively frequently; yjit breaking that will definitely be inconvenient for me! ## Implementation I have a draft implementation here on how I'd implement this: . It's currently missing tests & platform support (it only works on Linux aarch64). Also, it implements unwind info generation, so unwinding can work _through_ yjit code, but it does not currently emit symbols to give _names_ to those yjit frames. My PR contains a document which explains how the Linux interfaces for registering unwind info for JIT'd code work, so I won't duplicate that information here. The biggest implementation question I had is around the use of Rust crates. Currently, I prototyped my implementation using the gimli & object crates, for generating DWARF info and ELF binaries. However, the yjit build does purposefully does not use cargo & external crates for release builds. There are a few different ways we could go here: * Don't use the gimli & object crates; instead, re-implement all debug info & object file generation code in yjit. * Don't use the crates; instead, link againt C libraries to provide this functionality & call them from Rust (perhaps some combination of libelf, libdw, libbfd, or llvm might do what we need) * Use cargo after all for the release build & download the crates at build-time * Use cargo for the release build, but vendor everything, so the build doesn't need to download anything * Only make unwind info generation available in dev mode where cargo is used, and so mark the gimli/object dependencies as optional in Cargo.toml. We'd need to decide on one of these approaches for this proposal to work. I don't really have a strong sense of the pros/cons of each. (Side note - my PR actually depends on a _fork_ of gimli - I've been discussing adding the needed interfaces upstream here: https://github.com/gimli-rs/gimli/issues/648). ## Benchmarks I ran the yit-bench suite on my branch and compared it to Ruby master: * My branch: https://gist.github.com/KJTsanaktsidis/5741a9f64e5cd75cdf5fedd846091a4f * Ruby master: https://gist.github.com/KJTsanaktsidis/592d3ebcf98f6745dfa3efbd30a25acf This is a (very simple) comparison: ``` -------------- ------------ ------------ --------------- bench yjit (ms) branch (ms) branch/yjit (%) activerecord 97.5 98.5 101.03% hexapdf 2415.3 2458.2 101.78% liquid-c 61.9 63.1 101.94% liquid-render 135.3 135.0 99.78% mail 104.6 105.5 100.86% psych-load 1887.1 1922.0 101.85% railsbench 1544.4 1556.0 100.75% ruby-lsp 88.4 89.5 101.24% sequel 147.5 151.1 102.44% binarytrees 303 305.6 100.86% chunky_png 1075.8 1079.4 100.33% erubi 392.9 392.3 99.85% erubi_rails 14.7 14.7 100.00% etanni 792.3 791.4 99.89% fannkuchredux 3815.9 3813.6 99.94% lee 1030.2 1039.2 100.87% nbody 49.2 49.3 100.20% optcarrot 4142 4143.3 100.03% ruby-json 2860.7 2874.0 100.46% rubykon 7906.6 7904.2 99.97% 30k_ifelse 348.7 345.4 99.05% 30k_methods 828.6 831.8 100.39% cfunc_itself 28.8 28.9 100.35% fib 34.4 34.5 100.29% getivar 115.5 109.7 94.98% keyword_args 37.7 38.0 100.80% respond_to 26 26.1 100.38% setivar 33.8 33.5 99.11% setivar_object 208.7 194.3 93.10% str_concat 52.6 52.2 99.24% throw 23.8 24.1 101.26% -------------- ------------ ------------ --------------- ``` It seems like the performance impact of generating and registering the debug info is marginal. -- https://bugs.ruby-lang.org/

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