[ruby-core:108294] [Ruby master Bug#18743] Enumerator#next / peek re-use each others stacktraces
From:
sos4nt <noreply@...>
Date:
2022-04-19 14:42:09 UTC
List:
ruby-core #108294
Issue #18743 has been reported by sos4nt (Stefan Schテシテ殕er).
----------------------------------------
Bug #18743: Enumerator#next / peek re-use each others stacktraces
https://bugs.ruby-lang.org/issues/18743
* Author: sos4nt (Stefan Schテシテ殕er)
* Status: Open
* Priority: Normal
* 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.
--
https://bugs.ruby-lang.org/
Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>