drop GIL while waiting for all threads to join

Author: TingDaoK

source/common.c

@@ -47,9 +47,14 @@ PyObject *aws_py_thread_join_all_managed(PyObject *self, PyObject *args) {
     }
     aws_thread_set_managed_join_timeout_ns(timeout_ns);
 
+    /* clang-format off */
+    Py_BEGIN_ALLOW_THREADS
+    /* Drop GIL to allow other threads callback into python to finish joining. */
     if (aws_thread_join_all_managed()) {
         Py_RETURN_FALSE;
     }
+    Py_END_ALLOW_THREADS
+    /* clang-format on */
 
     Py_RETURN_TRUE;
 }

test/test_s3.py

@@ -666,9 +666,10 @@ def before_fork(self):
                 CRT_S3_CLIENT = None
                 gc.collect()
                 self.assertTrue(shutdown_event.wait(self.timeout))
-                join_all_native_threads(timeout_sec=0.1)
+                self.assertTrue(join_all_native_threads(timeout_sec=0.1))
         except Exception as e:
             print(f"before_fork error: {e}")
+            # fail hard
             exit(-1)
 
     @unittest.skipIf(sys.platform.startswith('win') or sys.platform == 'darwin',