Fix import oneflow error (#6401)

* export initNumpyCAPI

* refine

* refine

* refine

* refine

* refine

* refine

oneflow/api/python/numpy/init_numpy_c_api.cpp

+/*
+Copyright 2020 The OneFlow Authors. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include <pybind11/pybind11.h>
+#include "oneflow/api/python/of_api_registry.h"
+#include "oneflow/core/common/maybe.h"
+#include "oneflow/extension/python/numpy.h"
+
+namespace py = pybind11;
+
+ONEFLOW_API_PYBIND11_MODULE("", m) {
+  m.def("InitNumpyCAPI", []() { return oneflow::numpy::InitNumpyCAPI().GetOrThrow(); });
+}

oneflow/core/common/registry_error.h

@@ -20,8 +20,9 @@ limitations under the License.
 
 namespace oneflow {
 
+// Note: there is a time interval between catching error and reporting an error,
+// any error occur in this interval can't be displayed.
 Maybe<void> CheckAndClearRegistryFlag();
-
 void CatchRegistryError(const std::function<Maybe<void>()>&);
 
 }  // namespace oneflow

oneflow/extension/python/numpy.cpp

@@ -60,15 +60,12 @@ Maybe<DataType> GetOFDataTypeFromNpArray(PyArrayObject* array) {
 // defined in numpy_internal.h
 // Reference:
 // https://numpy.org/doc/stable/reference/c-api/array.html#importing-the-api
-void InitNumpyCAPI() {
-  CatchRegistryError([]() -> Maybe<void> {
-    CHECK_ISNULL_OR_RETURN(PyArray_API);
-    CHECK_EQ_OR_RETURN(_import_array(), 0);
-    return Maybe<void>::Ok();
-  });
+Maybe<void> InitNumpyCAPI() {
+  CHECK_ISNULL_OR_RETURN(PyArray_API);
+  CHECK_EQ_OR_RETURN(_import_array(), 0)
+      << ". Unable to import Numpy array, try to upgrade Numpy version!";
+  return Maybe<void>::Ok();
 }
 
-COMMAND(InitNumpyCAPI());
-
 }  // namespace numpy
 }  // namespace oneflow

oneflow/extension/python/numpy_internal.h

@@ -40,5 +40,7 @@ Maybe<DataType> NumpyTypeToOFDataType(int np_array_type);
 
 Maybe<DataType> GetOFDataTypeFromNpArray(PyArrayObject* array);
 
+Maybe<void> InitNumpyCAPI();
+
 }  // namespace numpy
 }  // namespace oneflow

python/oneflow/__init__.py

@@ -19,6 +19,7 @@ import collections
 
 import oneflow._oneflow_internal
 
+oneflow._oneflow_internal.InitNumpyCAPI()
 oneflow._oneflow_internal.CheckAndClearRegistryFlag()
 Size = oneflow._oneflow_internal.Size
 device = oneflow._oneflow_internal.device