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/