Issue #18743 has been updated by nobu (Nobuyoshi Nakada). Seems find to me. One thing I concerned, `stop_exc` will be re-created every times, and no way to know where it was first used up. How about chaining by `cause`? ```diff diff --git a/enumerator.c b/enumerator.c index b33c1713718..1cc8f9108cf 100644 --- a/enumerator.c +++ b/enumerator.c @@ -30,6 +30,9 @@ #include "internal/rational.h" #include "ruby/ruby.h" +extern ID ruby_static_id_cause; +#define id_cause ruby_static_id_cause + /* * Document-class: Enumerator * @@ -787,8 +790,16 @@ get_next_values(VALUE obj, struct enumerator *e) { VALUE curr, vs; - if (e->stop_exc) - rb_exc_raise(e->stop_exc); + if (e->stop_exc) { + VALUE exc = e->stop_exc; + VALUE result = rb_attr_get(exc, id_result); + VALUE mesg = rb_attr_get(exc, idMesg); + if (!NIL_P(mesg)) mesg = rb_str_dup(mesg); + VALUE stop_exc = rb_exc_new_str(rb_eStopIteration, mesg); + rb_ivar_set(stop_exc, id_result, result); + rb_ivar_set(stop_exc, id_cause, exc); + rb_exc_raise(stop_exc); + } curr = rb_fiber_current(); ``` In the test, save `$!` at the first `rescue` then `assert_same(cause, exc.cause)`. ---------------------------------------- Bug #18743: Enumerator#next / peek re-use each others stacktraces https://bugs.ruby-lang.org/issues/18743#change-103096 * Author: sos4nt (Stefan Schüßler) * Status: Open * Priority: Normal * Assignee: ko1 (Koichi Sasada) * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- I encountered an odd behavior. If I rescue the `StopIteration` exception from `peek` and call `next` afterwards: (or vice-versa) ```ruby # enum.rb # 1 # 2 enum = [].each # 3 enum.peek rescue nil # 4 enum.next # 5 ``` it will show the stacktrace from the rescued `peek` call: ``` $ ruby enum.rb enum.rb:4:in `peek': iteration reached an end (StopIteration) from enum.rb:4:in `<main>' ``` Whereas the error should refer to `next` on line number 5. The same happens when calling `peek` after `next` or when having muliple `peek` / `next` calls: ```ruby # enum.rb # 1 # 2 enum = [].each # 3 enum.peek rescue nil # 4 enum.next rescue nil # 5 enum.peek rescue nil # 6 puts "line #{__LINE__}" # 7 enum.next # 8 ``` The stacktrace from the first (rescued) `peek` or `next` call will be shown which doesn't reflect the actual error location: ``` $ ruby enum.rb line 7 enum.rb:4:in `peek': iteration reached an end (StopIteration) from enum.rb:4:in `<main>' ``` This is very confusing when debugging code. ---Files-------------------------------- 01-Recreate-stacktrace-enumerator.patch (1.29 KB) -- https://bugs.ruby-lang.org/