Issue #20968 has been updated by jeremyevans0 (Jeremy Evans). This doesn't seem like a bug to me. `Array#fetch_values` is in the backtrace, just not the top frame. This isn't the only core method with the behavior: ```ruby 1.ceildiv(0) # <internal:numeric>:304:in 'Integer#div': divided by 0 (ZeroDivisionError) # from <internal:numeric>:304:in 'Integer#ceildiv' ``` As more core methods are implemented in Ruby, this situation will occur more frequently. Can you explain why you think this is a bug? This is the expected behavior for most methods in the standard library, as well as most methods in gems. Any method written in Ruby that calls other methods will have this behavior, so I think it is OK that core methods are allowed to have this behavior. ---------------------------------------- Bug #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-111080 * Author: koic (Koichi ITO) * Status: Open * ruby -v: ruby 3.4.0dev (2024-12-19T04:44:56Z master 2783868de2) +PRISM [x86_64-darwin23] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by koic (Koichi ITO). Thank you for your prompt response. I hadn’t realized that the same issue occurs with `1.ceildiv(0)` as well. This is not a bug, but my concern arises from the asymmetry in how exceptions are displayed for `Array#fetch_values`. Even though `Array#fetch_values` was used incorrectly, the backtrace displays `Array#fetch` at the top, which was not explicitly called, and this caused some confusion. This is just a personal opinion, but it seems more natural for exception related to `Array#fetch_values` to show `Array#fetch_values` itself instead of the internal implementation of `Array#fetch`. This is not specific to `Array#fetch_values`, as the same can be said for cases like `1.ceildiv(0)`. ---------------------------------------- Bug #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-111095 * Author: koic (Koichi ITO) * Status: Open * ruby -v: ruby 3.4.0dev (2024-12-19T04:44:56Z master 2783868de2) +PRISM [x86_64-darwin23] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by mame (Yusuke Endoh). This issue was discussed briefly at the dev meeting and Matz agreed with koic's expectation. https://github.com/ruby/dev-meeting-log/blob/47882270bd90fb0027e8fe62e421b39... --- The following is my opinion. I agree that this is not a bug, but I think koic's expectations are clearly better than the current from a user benefit perspective, not from a consistency perspective. I think it is significantly unlikely that `<internal:array>:211` is valuable information for user to debug a bug. It would be more convenient to combine `<internal>` backtraces into one and substitute the name of the calling Ruby source file and line number, as in the current C-implemented method. ---------------------------------------- Bug #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112027 * Author: koic (Koichi ITO) * Status: Open * ruby -v: ruby 3.4.0dev (2024-12-19T04:44:56Z master 2783868de2) +PRISM [x86_64-darwin23] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by jeremyevans0 (Jeremy Evans). My thinking is inline with @Eregon 's. It's significantly more work to try to modify the backtraces to omit `<internal:` entries. Ultimately, I think that hiding such entries results in less helpful information. If we could show the file and line for C functions, that would be useful for debugging. I assume the only reason we don't is that doing so is not feasible. Note that even if we hide the `<internal:` methods, you still have the same issue for any method that is defined in C and calls another C or Ruby method in a way that pushes a VM frame: ``` $ ruby -e "Class.new.new(1)" -e:1:in `initialize': wrong number of arguments (given 1, expected 0) (ArgumentError) Class.new.new(1) ^ from -e:1:in `new' from -e:1:in `<main>' ``` Note that I never overrode `initialize`. I am calling `new`, but `initialize` is showing up in the backtrace even though both `new` and `initialize` are defined in C. The internal reason for this is because `Class.new` uses `rb_funcallv_kw` to call `Obejct#initialize`, which pushes a VM frame. That being said, if we do want to change behavior of this only for `<internal:` entries, the `Primitive.attr! :c_trace` approach mentioned by @byroot seems preferable to modifying the backtrace internals. Should we just add that to all `<internal:` methods that call other methods? ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112041 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by ioquatix (Samuel Williams). I also agree this is not a bug and the expanded stack trace is good. But let me talk about my experience with Objective-C. A long time ago, I created Objective-C applications with Apple's Cocoa framework. It uses "delegate" pattern extensively which are essentially callbacks wrapped in objects with a well defined interface. In particular, Apple's frameworks were soemtimes buggy, but using adebugger, all the intermediate stack traces are hidden. So a stack trace (or thread backtrace) would show something like: ``` <your delegate implementation> <hidden internal function call> <hidden internal function call> <hidden internal function call> <possibly user code> ``` This made debugging EXTREMELY difficult because it was impossible to figure out what the expectations of the `<hidden internal function call>` were - no way to correlate it back to code or even inspect what was going on. Now, back to Ruby. I greatly prefer visibility in the stack trace. If something goes wrong (usual cause of exception with backtrace), even if it was the user code that made a mistake (e.g. the implementation of `hash` or something invoked by the internal code), it can be extremely helpful if the user can easily find that code in order to read it and debug their own code. This difficulty with Objective-C was one of the reasons I eventually stopped using it - the frameworks were too opaque and it made debugging extremely painful. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112157 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by byroot (Jean Boussier).

He reiterated that <internal: should not be displayed.

Should it even exist then? Because a "simple" solution would be simply make `Primitive.attr! :c_trace` the default rather than a opt-in thing. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112293 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by Eregon (Benoit Daloze). matz (Yukihiro Matsumoto) wrote in #note-13:

It should not be displayed. I don't care much if it exists. It should be decided according to the demand and implementation easiness.

FWIW, I am pretty sure TruffleRuby will never do that change. It would hide crucial information for both users and implementation developers, as I detailed above. We tried it in TruffleRuby, it was bad for both users and devs, we learned from it. It's like hiding crucial debugging information from segfault reports, who would want that? To be frank, I think it's shortsighted to do anything about this now. The problem of hiding will naturally become more evident as more of the Ruby core library is defined in Ruby. `Primitive.attr! :c_trace` can be used on `Array#fetch_values`, I don't really care about that specific one (except obviously we wouldn't hide it on TruffleRuby). But in general I think it's clearly a mistake to hide those backtrace entries which are helpful to understand behavior. It's like silently swallowing exceptions, it wastes tons of time in debugging for little value. It's also not the Ruby VM's job to hide frames, it should show all of them to ease debugging. Test frameworks might choose to filter stacktraces or display them differently, that's fine, and it's easy. All the test frameworks that I know and filter also provide an option to opt out of that filtering, proving that it's sometimes necessary to have the full stacktrace. There are no practical problems with it (just people learning about it/getting used to it because it was less common). In fact `<internal` exists since at least Ruby 2.3, probably even before. A common example, from Ruby 3.0 is `Kernel#tap` (AFAIK nobody ever complained or got confused about it): ``` $ ruby -e 'tap { raise "oops" }' -e:1:in `block in <main>': oops (RuntimeError) from <internal:kernel>:90:in `tap' from -e:1:in `<main>' ``` The suggested change would result in: ``` $ ruby -e 'tap { raise "oops" }' -e:1:in `block in <main>': oops (RuntimeError) from -e:1:in `tap' from -e:1:in `<main>' ``` which is no better and would make debugging far worse if there are multiple `<internal` frames. --- I'll give another example where the proposed change hurts understandability: Suppose Method#call is defined in Ruby code, then this change proposes to go from: ``` ... from bar.rb:1:in 'Bar#bar' from foo.rb:1:in 'block in Foo#foo' from <internal:kernel>:90:in 'Kernel#tap' from <internal:method>:111:in 'Method#call' from foo.rb:1:in 'Foo#foo' ... ``` to ``` ... from bar.rb:1:in 'Bar#bar' from foo.rb:1:in 'block in Foo#foo' from <internal:method>:111:in 'Method#call' from foo.rb:1:in 'Foo#foo' ... ``` So now Method#call can call a block directly? No, it's just the stacktrace betraying you by hiding crucial information. (there are more examples which don't even need methods to move from C to Ruby in previous comment https://bugs.ruby-lang.org/issues/20968#note-6) ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112320 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by Eregon (Benoit Daloze). mame (Yusuke Endoh) wrote in #note-15:

In any case, it was reaffirmed that matz strongly prefers that `<internal:` not be displayed.

@matz Is that because there is the word "internal" in there and so it sounds like exposing internals? How about `<core:` or `<core-library:` then? That would make it clear those are core library methods. As I explained in my previous reply `<internal:` has been there since many years (since `gem_prelude.rb`/`prelude.rb` exist) and has caused no real issues (just a few incorrect assumptions in gems which have been fixed since). If it wasn't for this issue, we would probably not even discuss this, and most (all I think) people on this issue already agreed it is not a bug and not a problem in practice. If it's about consistency of C-defined vs Ruby-defined core methods in the backtrace, we could maybe go the other way around, @jeremyevans0 said earlier in the thread:

If we could show the file and line for C functions, that would be useful for debugging. I assume the only reason we don't is that doing so is not feasible.

It should be feasible with a C preprocessor macro using `__FILE__` and `__LINE__`. In fact, I think it's confusing and misleading that methods defined in C report that they are defined in the caller Ruby file (which is obviously incorrect, they are not defined there). Detailed in the 2nd part of [this comment](https://bugs.ruby-lang.org/issues/20968#note-6) after the horizontal line. I think that illustrates clearly that people got used to this "confusing/misleading way to report the stacktrace for C-defined methods", and so they are surprised to see something else for Ruby-defined core methods. But I believe it is just a matter of getting used to it. Passed the initial "surprise" it makes total sense because it's no different than a regular method defined in Ruby code (except the file prefix). [This comment](https://bugs.ruby-lang.org/issues/20968#note-9) demonstrates that the current stacktrace for `Array#fetch_values` is very consistent as if the method was defined in a Ruby file in some gem or so. And on the contrary, changing stacktraces as proposed would introduce a 3rd kind of entry in the backtrace, which I think is evident it will cause more confusion, due to hiding crucial information in at least some cases. --- BTW `<internal:` is used for filtering in `Kernel#warn` and in https://github.com/rubygems/rubygems/blob/7ab9c82b1b01614b052a57ccb49370cea9... It's also intentional that `Kernel#warn` filters out core methods, since those should definitely not emit warnings (or if they do the cause is probably the caller, if not then it's a CRuby bug). So `<internal:` is a useful concept besides just the core library. In fact a [quick search](https://github.com/search?q=%3Cinternal+language%3ARuby+&type=code) shows it's used in various gem, a well-known example is [Sinatra](https://github.com/sinatra/sinatra/blob/c235249abaafa2780b540aca1813dfcf3d17...). So removing `<internal:` in CRuby would likely cause some incompatibility. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112333 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by Dan0042 (Daniel DeLorme).

In any case, it was reaffirmed that matz strongly prefers that `<internal:` not be displayed.

I somewhat agree that showing "internal" makes it look like we're leaking internal implementation details, but then what about this: <array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <array>:211:in 'block in Array#fetch_values' from <array>:211:in 'Array#map!' from <array>:211:in 'Array#fetch_values' from -e:1:in '<main>' Already such a simple cosmetic change is enough to improve the appearance of the backtrace imho. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-112646 * Author: koic (Koichi ITO) * Status: Open ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by mame (Yusuke Endoh). I have updated the behavior to (mostly) suppress the display of `<internal:...>` frames in a backtrace. The algorithm works as follows: * When internal frames appear in a sequence, it retains only one frame -- the one directly called from Ruby code. * The location information of the internal frame is now backpatched with the filename and line number of the caller (similar to how we handle C frames). If you encounter any cases where this algorithm does not work well, please let me know. Please note that this transformation is not applied when using the debug inspector API or `TracePoint#path`, so `<internal:...>` will still appear in those cases. This behavior may change in the future. See also #21395. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-113784 * Author: koic (Koichi ITO) * Status: Closed ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/

Issue #20968 has been updated by mame (Yusuke Endoh). Thanks, I fixed the issue by commit:3546cedde3f6f46f00fd67b73081cbfbb83144de. ``` $ ./miniruby -ve '[1,2].inject(:tap)' ruby 3.5.0dev (2025-06-24T02:39:58Z master 3546cedde3) +PRISM [x86_64-linux] -e:1:in 'Kernel#tap': wrong number of arguments (given 1, expected 0) (ArgumentError) from -e:1:in 'Enumerable#inject' from -e:1:in '<main>' ``` There was another problem that the class to which a method belonged was not displayed when an ArgumentError is raised at the time of argument passing. The commit fixes that problem as well: * ruby 3.4.2: `<internal:kernel>:89:in 'tap': ...` * master: `-e:1:in 'Kernel#tap': ...`. ---------------------------------------- Misc #20968: `Array#fetch_values` unexpected method name in stack trace https://bugs.ruby-lang.org/issues/20968#change-113822 * Author: koic (Koichi ITO) * Status: Closed ---------------------------------------- It seems that the current Ruby implementation is displaying unexpected method name in stack trace. ## Expected Similar to `Hash#fetch_values`, the method name `Array#fetch_values` is expected to be displayed in the stack trace. ```console $ ruby -e '{k: 42}.fetch_values(:unknown)' -e:1:in 'Hash#fetch_values': key not found: :unknown (KeyError) from -e:1:in '<main>' $ ruby -e '[1].fetch_values(42)' -e:1:in 'Array#fetch_values': index 42 outside of array bounds: -1...1 (IndexError) from -e:1:in '<main>' ``` ## Actual The stack trace displays the `Array#fetch` method, which user is not aware of, along with the `<internal.array>` stack trace. ```console $ ruby -e '[1].fetch_values(42)' <internal:array>:211:in 'Array#fetch': index 42 outside of array bounds: -1...1 (IndexError) from <internal:array>:211:in 'block in Array#fetch_values' from <internal:array>:211:in 'Array#map!' from <internal:array>:211:in 'Array#fetch_values' from -e:1:in '<main>' ``` It likely requires an approach such as implementing it in C, as suggested in https://github.com/ruby/ruby/pull/11555. -- https://bugs.ruby-lang.org/