From 9145e5823ea1af98ef31709d0a1a4a3836f65898 Mon Sep 17 00:00:00 2001
From: Robert Connell <robert_connell@apple.com>
Date: Wed, 10 Dec 2025 13:58:52 -0500
Subject: [PATCH] Ensure call to unsafe_await is not called from Swifts
 concurrency system

---
 Sources/Basics/Concurrency/ConcurrencyHelpers.swift | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Sources/Basics/Concurrency/ConcurrencyHelpers.swift b/Sources/Basics/Concurrency/ConcurrencyHelpers.swift
index 2837bea4b95..ad6513f0add 100644
--- a/Sources/Basics/Concurrency/ConcurrencyHelpers.swift
+++ b/Sources/Basics/Concurrency/ConcurrencyHelpers.swift
@@ -27,6 +27,12 @@ public enum Concurrency {
 
 @available(*, noasync, message: "This method blocks the current thread indefinitely. Calling it from the concurrency pool can cause deadlocks")
 public func unsafe_await<T: Sendable>(_ body: @Sendable @escaping () async -> T) -> T {
+    withUnsafeCurrentTask { task in
+        if task != nil {
+            fatalError("This function must not be invoked from the Swift Concurrency thread pool.")
+        }
+    }
+    
     let semaphore = DispatchSemaphore(value: 0)
 
     let box = ThreadSafeBox<T>()