fix(imperative): sync command queue at exit

GitOrigin-RevId: c0d6aad27535b5a42d22124fc8c4662b02707a7c

imperative/python/megengine/__init__.py

@@ -10,6 +10,7 @@ import os
 import sys
 import platform
 import ctypes
+import atexit
 
 if sys.platform == "win32":
     lib_path = os.path.join(os.path.dirname(__file__), "core/lib")
@@ -71,6 +72,7 @@ if sys.platform == "win32":
     kernel32.SetErrorMode(old_error_mode)
 
 from .core._imperative_rt.utils import _set_fork_exec_path_for_timed_func
+from .core._imperative_rt.imperative import sync
 from .device import *
 from .logger import enable_debug_log, get_logger, set_log_file, set_log_level
 from .serialization import load, save
@@ -83,4 +85,7 @@ _set_fork_exec_path_for_timed_func(
     os.path.join(os.path.dirname(__file__), "utils", "_timed_func_fork_exec_entry.py"),
 )
 
+atexit.register(sync)
+
+del sync
 del _set_fork_exec_path_for_timed_func

imperative/python/test/conftest.py

 import os
 import sys
 
+import pytest
+
+from megengine.core._imperative_rt.imperative import sync
+
 sys.path.append(os.path.join(os.path.dirname(__file__), "helpers"))
+
+
+def pytest_runtest_teardown():
+    sync()

imperative/src/impl/interpreter_impl.cpp

@@ -175,7 +175,9 @@ void ChannelImpl::free(TensorInfo* ptr) {
     m_pool.free(ptr);
 }
 
-ChannelImpl::~ChannelImpl() {}
+ChannelImpl::~ChannelImpl() {
+    close();
+}
 
 void ChannelImpl::produce_tensor(TensorInfo* dest, TensorPtr ptr) {
     MGB_LOCK_GUARD(m_mutex);