Merge #19340: Preserve the `LockData` initial state if "potential deadlock detected" exception thrown

63e9e40b73507b0c9361fc8728d4e97fd72c9ec9 test: Add LockStackEmpty() (Hennadii Stepanov)
42b2a953735457cbf7b62a18b89811a66e573298 test: Repeat deadlock tests (Hennadii Stepanov)
1f96be25b020a56afa330286ee4f241aa14d3983 Preserve initial state if push_lock() throws exception (Hennadii Stepanov)

Pull request description:

  On master (e3fa3c7d671e34038a262bb2db16b30bee82153d) if the `push_lock()` throws the "potential deadlock detected" exception (via the `potential_deadlock_detected()` call), the `LockData` instance internal state differs from one when the `push_lock()` was called. This non-well behaviour makes (at least) testing brittle.

  This PR preserves the `LockData` instance initial state if `push_lock()` throws an exception, and improves the `sync_tests` unit test.

ACKs for top commit:
  MarcoFalke:
    re-ACK 63e9e40b73
  vasild:
    ACK 63e9e40

Tree-SHA512: 7679182154ce5f079b44b790faf76eb5f553328dea70a326ff6b600db70e2f9ae015a33a104ca070cb660318280cb79b6b42e37ea5166f26f9e627ba721fcdec

1 files changed, 6 insertions, 0 deletions

diff --git a/src/test/sync_tests.cpp b/src/test/sync_tests.cpp
index 3ea8714f3a..19029ebd3c 100644
--- a/src/test/sync_tests.cpp
+++ b/src/test/sync_tests.cpp
@@ -14,6 +14,7 @@ void TestPotentialDeadLockDetected(MutexType& mutex1, MutexType& mutex2)
     {
         LOCK2(mutex1, mutex2);
     }
+    BOOST_CHECK(LockStackEmpty());
     bool error_thrown = false;
     try {
         LOCK2(mutex2, mutex1);
@@ -21,6 +22,7 @@ void TestPotentialDeadLockDetected(MutexType& mutex1, MutexType& mutex2)
         BOOST_CHECK_EQUAL(e.what(), "potential deadlock detected: mutex1 -> mutex2 -> mutex1");
         error_thrown = true;
     }
+    BOOST_CHECK(LockStackEmpty());
     #ifdef DEBUG_LOCKORDER
     BOOST_CHECK(error_thrown);
     #else
@@ -40,9 +42,13 @@ BOOST_AUTO_TEST_CASE(potential_deadlock_detected)
 
     RecursiveMutex rmutex1, rmutex2;
     TestPotentialDeadLockDetected(rmutex1, rmutex2);
+    // The second test ensures that lock tracking data have not been broken by exception.
+    TestPotentialDeadLockDetected(rmutex1, rmutex2);
 
     Mutex mutex1, mutex2;
     TestPotentialDeadLockDetected(mutex1, mutex2);
+    // The second test ensures that lock tracking data have not been broken by exception.
+    TestPotentialDeadLockDetected(mutex1, mutex2);
 
     #ifdef DEBUG_LOCKORDER
     g_debug_lockorder_abort = prev;