More tsan builds

.github/workflows/mac-other-builds.yml

@@ -0,0 +1,36 @@
+name: Mac Sanitizer Builds
+
+on: [push, pull_request]
+
+env:
+  CXXFLAGS: -fsanitize=thread,undefined
+
+jobs:
+  build:
+    # From macos-14 forward, the baseline "macos-X" image is Arm based,
+    # and not Intel based.
+    runs-on: ${{matrix.image}}
+    strategy:
+      fail-fast: false
+      matrix:
+        image: [macos-13, macos-14]
+        build_type: [Debug, Release]
+        std: [14, 17]
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Configure
+      
+      run: |
+        cmake --preset all-tests -GNinja \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCATCH_BUILD_EXTRA_TESTS=ON \
+              -DCATCH_ENABLE_WERROR=OFF
+
+    - name: Build
+      run: cmake --build build
+
+    - name: Test
+      run: ctest --test-dir build -R ThreadSafetyTests --timeout 21600 --verbose

src/catch2/internal/catch_thread_support.hpp

@@ -23,10 +23,10 @@ namespace Catch {
         using Mutex = std::mutex;
         using LockGuard = std::lock_guard<std::mutex>;
         struct AtomicCounts {
-            std::atomic<std::uint64_t> passed = 0;
-            std::atomic<std::uint64_t> failed = 0;
-            std::atomic<std::uint64_t> failedButOk = 0;
-            std::atomic<std::uint64_t> skipped = 0;
+            std::atomic<std::uint64_t> passed{ 0 };
+            std::atomic<std::uint64_t> failed{ 0 };
+            std::atomic<std::uint64_t> failedButOk{ 0 };
+            std::atomic<std::uint64_t> skipped{ 0 };
         };
 #else // ^^ Use actual mutex, lock and atomics
       // vv Dummy implementations for single-thread performance

tests/ExtraTests/CMakeLists.txt

@@ -553,3 +553,17 @@ set_tests_properties(AmalgamatedFileTest
   PROPERTIES
     PASS_REGULAR_EXPRESSION "All tests passed \\(14 assertions in 3 test cases\\)"
 )
+
+add_executable(ThreadSafetyTests
+  ${TESTS_DIR}/X94-ThreadSafetyTests.cpp
+)
+target_link_libraries(ThreadSafetyTests Catch2_buildall_interface)
+target_compile_definitions(ThreadSafetyTests PUBLIC CATCH_CONFIG_EXPERIMENTAL_THREAD_SAFE_ASSERTIONS)
+add_test(NAME ThreadSafetyTests
+  COMMAND ThreadSafetyTests -r compact
+)
+set_tests_properties(ThreadSafetyTests
+  PROPERTIES
+    PASS_REGULAR_EXPRESSION "assertions: 801 | 400 passed | 401 failed"
+    RUN_SERIAL ON
+)

tests/ExtraTests/X94-ThreadSafetyTests.cpp

@@ -0,0 +1,44 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+/**\file
+ * Test that assertions and messages are thread-safe.
+ *
+ * This is done by spamming assertions and messages on multiple subthreads.
+ * In manual, this reliably causes segfaults if the test is linked against
+ * a non-thread-safe version of Catch2.
+ *
+ * The CTest test definition should also verify that the final assertion
+ * count is correct.
+ */
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <atomic>
+#include <thread>
+#include <vector>
+
+TEST_CASE( "Failed REQUIRE in the main thread is fine" ) {
+    std::vector<std::thread> threads;
+    for ( size_t t = 0; t < 4; ++t) {
+        threads.emplace_back( [t]() {
+            CAPTURE(t);
+            for (size_t i = 0; i < 100; ++i) {
+                CAPTURE(i);
+                CHECK( false );
+                CHECK( true );
+            }
+        } );
+    }
+
+    for (auto& t : threads) {
+        t.join();
+    }
+
+    REQUIRE( false );
+}