Merge pull request #43 from Photoroom/ben/skip_deserialize_empty_image

[Another nit] Opening an empty image would crash in python space

python/go_types.py

@@ -7,6 +7,9 @@
 
 
 def uint8_array_to_numpy(go_array):
+    if len(go_array.Data) == 0:
+        return None
+
     # By convention, arrays which are already serialized as jpg or png are not reshaped
     # We export them from Go with a Channels dimension of -1 to mark them as dimensionless.
     # Anything else is a valid number of channels and will thus lead to a reshape
@@ -29,6 +32,9 @@ def uint8_array_to_numpy(go_array):
 
 
 def go_array_to_numpy(go_array) -> Optional[np.ndarray]:
+    if len(go_array.Data) == 0:
+        return None
+
     # Generic numpy-serialized array
     bytes_buffer = bytes(go.Slice_byte(go_array.Data))
     try:
@@ -39,7 +45,10 @@ def go_array_to_numpy(go_array) -> Optional[np.ndarray]:
         return None
 
 
-def go_array_to_pil_image(go_array):
+def go_array_to_pil_image(go_array) -> Optional[Image.Image]:
+    if len(go_array.Data) == 0:
+        return None
+
     # Zero copy conversion of the image buffer from Go to PIL.Image
     np_array = uint8_array_to_numpy(go_array)
     if go_array.Channels <= 0:

python/test_datago_db.py

@@ -147,6 +147,16 @@ def test_has_tags():
     assert "v4_trainset_hq" in sample.Tags, "v4_trainset_hq should be in the tags"
 
 
+def test_empty_image():
+    client_config = get_json_config()
+    client_config["source_config"]["require_images"] = False
+
+    dataset = get_dataset(client_config)
+
+    # Just check that accessing the sample in python does not crash
+    _ = next(iter(dataset))
+
+
 def no_test_jpg_compression():
     # Check that the images are compressed as expected
     client_config = get_json_config()