P2370R1 Stacktrace from exception (Andrei Nekrashevich, Antony Polukhin)

Mailing review 26-07-2021-13-09-2001

Lots of interest for this paper to land in 23 along the already approved stacktrace proposal.
A R1 was provided during the review addressing most of the concerns and feedback offered during the review.
A core expert offered some wording review

We probably still want to hear from implementers directly about the potential issues pertaining to ABI stability.

Given all the feedbacks were addressed and reviewers are happy with the general design and wording,
I recommend that this paper is reviewed during a LEWG telecon.

Deferring to C++26 due to lack of time.

P2370R2 Stacktrace from exception (Andrei Nekrashevich, Antony Polukhin)

2022-06-21 Library Evolution Telecon

P2370R2: Stacktrace from exception

2022-06-21 Library Evolution Telecon Minutes

P2490R0: Zero-overhead exception stacktraces

2022-06-21 Library Evolution Telecon Minutes

Chair: Bryce Adelstein Lelbach

Minute Taker: Ben Craig

Champion: Antony Polukhin (P2370) & Ed Catmur (P2490)

Start: 2022-06-21 11:51 Eastern

Does P2370 have:

• Examples?
  • Yes
• Field experience?
  • Yes. The field experience indicates that this can be done without
    an ABI break.
• Performance considerations?
  • Yes. Performance overheads were a source of discussion with this proposal.
• Discussion of prior art?
  • Yes.
• Wording?
  • Yes.
• Feature test macro?
  • Yes.

This needs to be seen by Evolution.

P2380R2 proposes capturing the stacktrace at the throw side and allows you to globally or per-thread enable/disable capturing stacktraces.

P2490R0 proposes to capture the stacktrace at entering the catch block rather than at the throw side.

End: 12:17

Summary

P2380R2 (Stacktrace from exceptions) and P2490R0 (Zero-overhead exception stacktraces) propose mechanisms for attaching stacktraces to exceptions.
P2380R2 proposes capturing the stacktrace at the throw side and allows you to globally or per-thread enable/disable capturing stacktraces.
P2490R0 proposes to capture the stacktrace at entering the catch block rather than at the throw side.

It became apparent during Library Evolution's review of these papers that they should be seen by Evolution first.
Once Evolution has decided upon a design direction for this feature, Library Evolution can review the Standard Library exposure of the feature.

Next Steps

Send P2380R2 (Stacktrace from exceptions) and P2490R0 (Zero-overhead exception stacktraces) to Evolution.

EWG saw this paper in the February 9th, 2023 morning session, and the following poll was taken:

Knowing our time is limited, EWG would like to see P2370R2 again, provided it includes language-level exploration/implementation experience.

Result: Not Consensus