From 5bbafeabd7c38bcf7c264769a48e973173fd0430 Mon Sep 17 00:00:00 2001
From: Bartosz Taudul <wolf@nereid.pl>
Date: Mon, 4 May 2026 01:13:25 +0200
Subject: [PATCH] Patch ppqsort to fix binary_semaphore release race.

---
 cmake/ppqsort-semaphore.patch | 14 ++++++++++++++
 cmake/vendor.cmake            |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 cmake/ppqsort-semaphore.patch

diff --git a/cmake/ppqsort-semaphore.patch b/cmake/ppqsort-semaphore.patch
new file mode 100644
index 00000000..911f7bc8
--- /dev/null
+++ b/cmake/ppqsort-semaphore.patch
@@ -0,0 +1,14 @@
+diff --git i/include/ppqsort/parallel/cpp/thread_pool.h w/include/ppqsort/parallel/cpp/thread_pool.h
+--- i/include/ppqsort/parallel/cpp/thread_pool.h
++++ w/include/ppqsort/parallel/cpp/thread_pool.h
+@@ -134,7 +134,9 @@ namespace ppqsort::impl::cpp {
+             alignas(parameters::cacheline_size) std::atomic<std::size_t> pending_tasks_{0};
+             alignas(parameters::cacheline_size) std::atomic<std::size_t> total_tasks_{0};
+             alignas(parameters::cacheline_size) std::atomic<bool> to_stop_{false};
+-            std::binary_semaphore threads_done_semaphore_{0};   // used to wait for all tasks to finish
++            // counting_semaphore: multiple workers may concurrently observe total_tasks_ == 0
++            // and call release(); a binary_semaphore would assert when the count exceeds 1.
++            std::counting_semaphore<> threads_done_semaphore_{0};
+             std::mutex mtx_priority_;
+             bool stopped = false;
+     };
diff --git a/cmake/vendor.cmake b/cmake/vendor.cmake
index 8a8a97d8..593cf37a 100644
--- a/cmake/vendor.cmake
+++ b/cmake/vendor.cmake
@@ -199,6 +199,7 @@ CPMAddPackage(
     VERSION 1.0.6
     PATCHES
         "${CMAKE_CURRENT_LIST_DIR}/ppqsort-nodebug.patch"
+        "${CMAKE_CURRENT_LIST_DIR}/ppqsort-semaphore.patch"
     EXCLUDE_FROM_ALL TRUE
 )