From 3570ff738ca18b379cd8f67384f69968ea5e72f7 Mon Sep 17 00:00:00 2001
From: Lucian Radu Teodorescu <lucteo@lucteo.ro>
Date: Wed, 14 Aug 2024 16:38:18 +0300
Subject: [PATCH] Fix race condition that would make the system context tests
 fail occasionally.

---
 .../__detail/__system_context_default_impl.hpp | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/exec/__detail/__system_context_default_impl.hpp b/include/exec/__detail/__system_context_default_impl.hpp
index 5e31e3443..5e9b88634 100644
--- a/include/exec/__detail/__system_context_default_impl.hpp
+++ b/include/exec/__detail/__system_context_default_impl.hpp
@@ -45,20 +45,26 @@ namespace exec::__system_context_default_impl {
 
     void set_value() noexcept {
       auto __op = __op_;
-      __r_->set_value();
-      __op->__destruct();
+      auto __r = __r_;
+      __op->__destruct(); // destroys the operation, including `this`.
+      __r->set_value();
+      // Note: when calling a completion signal, the parent operation might complete, making the
+      // static storage passed to this operation invalid. Thus, we need to ensure that we are not
+      // using the operation state after the completion signal.
     }
 
     void set_error(std::exception_ptr __ptr) noexcept {
       auto __op = __op_;
-      __r_->set_error(__ptr);
-      __op->__destruct();
+      auto __r = __r_;
+      __op->__destruct(); // destroys the operation, including `this`.
+      __r->set_error(__ptr);
     }
 
     void set_stopped() noexcept {
       auto __op = __op_;
-      __r_->set_stopped();
-      __op->__destruct();
+      auto __r = __r_;
+      __op->__destruct(); // destroys the operation, including `this`.
+      __r->set_stopped();
     }
   };