`STDEXEC_ENABLE_EXTRA_TYPE_CHECKING` no longer checks senders in `connect` (since #1809)

Ouverte
  • Quelque chose ne va pas ?
#2,407 0 commentaires 0 réactions 0 personnes assignées Voir sur GitHub

Les mainteneurs répondent en général sous 1 jour

Personne n'a encore pris cette issue.

Évaluation

Difficulté
4/5
Temps estimé
3-5 jours
Accessibilité débutants
25/100
Type d'issue
Bug
Clarté
Plutôt claire
Activité
Active
Stack technique
cmake, cpp
Domaine
build-system, devtools

Piste de recherche

The check lives in connect_t::operator() and the debug receiver __debug::__receiver. The any_sender failure is in test/exec/test_any_sender.cpp, at the __nothrow_move_constructible assert in __fwd in __env.hpp. The CMake SYSTEM include setting is the other part. First the maintainers must decide whether the flag should keep working. If it should, done means the mismatched-completion case warns through connect, the any_sender test compiles with the flag on, and a build-failure test exists.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Description

With STDEXEC_ENABLE_EXTRA_TYPE_CHECKING, connect used to instantiate completion_signatures_of_t for the sender it connects, so __debug_sender warned when a sender completes with something it did not declare. That came from #1070 (for #1065). The new connect from #1809 no longer does this, so now only code that names completion_signatures_of_t gets the check.

Example: a sender that declares set_value_t(int) but completes with set_value(std::move(rcvr), v), where v is an int lvalue. Compiled with -I<stdexec>/include -DSTDEXEC_ENABLE_EXTRA_TYPE_CHECKING, with GCC 12 and Clang 21:

sync_wait(sndr) let_value(sndr, f) completion_signatures_of_t<Sndr>
before #1809 (6d568715~1) warning warning warning
#1809 and main (e780d360) no warning no warning warning

I tried to put the check back into connect_t::operator(), and found two more things:

  • With the flag on, that breaks test/exec/test_any_sender.cpp with GCC 12 and Clang 21. when_any inside an any_sender then gets connected to __debug::__receiver, and static_assert(__nothrow_move_constructible<_Env>) in __fwd (__env.hpp) fails for the type-erased receiver environment. Main compiles that file with the flag on.
  • Since ca3797c3, the CMake target adds the include directory as SYSTEM. GCC and Clang don't report warnings from system headers, so with -isystem instead of -I none of the cases above warn, also before #1809. So CMake users don't see these warnings at all.

Is the flag still meant to work? If yes, I'd be happy to make a PR that restores the check in connect, makes it work with any_sender, and adds a build-failure test. For the SYSTEM part, one option is to not mark the include directory SYSTEM when STDEXEC_ENABLE_EXTRA_TYPE_CHECKING is ON. If you'd rather drop the flag, that's fine too.

Claude (Anthropic) was used as assistant.

Langage dominant
C++
Étoiles
2.5k
Forks
284
Merge moyen
2 j 32 min
PR mergées (30 j)
88

Préparer son environnement

Ce projet ne fournit ni conteneur de développement, ni Dockerfile, ni guide de contribution : l'installation est à votre charge. Commencez par son README, et consultez notre guide de la première contribution pour les étapes générales.

Par où commencer

  1. Lisez l'issue en entier, puis le guide de contribution du projet.
  2. Signalez en commentaire que vous la prenez — cela évite que deux personnes fassent le même travail.
  3. Forkez le dépôt et travaillez sur une branche.
  4. Ouvrez une pull request qui référence le numéro de l'issue.

Autres issues de NVIDIA/stdexec

Toutes les issues de NVIDIA/stdexec

Issues similaires

Plus d'issues C++

Recevez les nouvelles issues par e-mail

Un résumé court des issues GitHub adaptées aux débutants.