[libcxx-commits] [libcxx] [libc++] Prevent std::terminate in promise<void> destructor race (PR #221258)

[via libcxx-commits]

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@@ -144,8 +145,12 @@ promise<void>::promise() : __state_(new __assoc_sub_state) {}
 promise<void>::~promise() {
   if (__state_) {
 #if _LIBCPP_HAS_EXCEPTIONS
-    if (!__state_->__has_value() && __state_->use_count() > 1)
-      __state_->set_exception(make_exception_ptr(future_error(future_errc::broken_promise)));
+    if (!__state_->__has_value() && __state_->use_count() > 1) {
+      try {
+        __state_->set_exception(make_exception_ptr(future_error(future_errc::broken_promise)));
+      } catch (...) {
+      }
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huixie90 wrote:

i am not sure about this. In case it does throw, this implementation will leave the shared state in an indeterministic state, whereas the standard requires it to store an `future_error`
https://eel.is/c++draft/futures.state#7.1.1

In that sense, I would argue `std::terminate` is better than a silent wrong answer

https://github.com/llvm/llvm-project/pull/221258