!9306 fix ndarray field without type in mindrecord

From: @jonyguo
Reviewed-by: @pandoublefeng,@liucunwei
Signed-off-by: @liucunwei

mindspore/mindrecord/shardwriter.py

@@ -196,10 +196,10 @@ class ShardWriter:
         def int_to_bytes(x: int) -> bytes:
             return x.to_bytes(8, 'big')
         merged = bytes()
-        for _, v in blob_data.items():
+        for field, v in blob_data.items():
             # convert ndarray to bytes
             if isinstance(v, np.ndarray):
-                v = v.tobytes()
+                v = v.astype(self._header.schema[field]["type"]).tobytes()
             merged += int_to_bytes(len(v))
             merged += v
         return merged

tests/ut/python/mindrecord/test_mindrecord_base.py

@@ -964,3 +964,39 @@ def test_write_read_process_with_multi_bytes_and_array():
 
     os.remove("{}".format(mindrecord_file_name))
     os.remove("{}.db".format(mindrecord_file_name))
+
+def test_write_read_process_without_ndarray_type():
+    mindrecord_file_name = "test.mindrecord"
+    # field: mask derivation type is int64, but schema type is int32
+    data = [{"file_name": "001.jpg", "label": 43, "score": 0.8, "mask": np.array([3, 6, 9]),
+             "segments": np.array([[5.0, 1.6], [65.2, 8.3]], dtype=np.float32),
+             "data": bytes("image bytes abc", encoding='UTF-8')}
+            ]
+    writer = FileWriter(mindrecord_file_name)
+    schema = {"file_name": {"type": "string"},
+              "label": {"type": "int32"},
+              "score": {"type": "float64"},
+              "mask": {"type": "int32", "shape": [-1]},
+              "segments": {"type": "float32", "shape": [2, 2]},
+              "data": {"type": "bytes"}}
+    writer.add_schema(schema, "data is so cool")
+    writer.write_raw_data(data)
+    writer.commit()
+
+    reader = FileReader(mindrecord_file_name)
+    count = 0
+    for index, x in enumerate(reader.get_next()):
+        assert len(x) == 6
+        for field in x:
+            if isinstance(x[field], np.ndarray):
+                print("output: {}, input: {}".format(x[field], data[count][field]))
+                assert (x[field] == data[count][field]).all()
+            else:
+                assert x[field] == data[count][field]
+        count = count + 1
+        logger.info("#item{}: {}".format(index, x))
+    assert count == 1
+    reader.close()
+
+    os.remove("{}".format(mindrecord_file_name))
+    os.remove("{}.db".format(mindrecord_file_name))