fix: preserve list meanings

google/cloud/datastore/helpers.py

@@ -18,7 +18,6 @@
 """
 
 import datetime
-import itertools
 
 from google.protobuf import struct_pb2
 from google.type import latlng_pb2
@@ -43,36 +42,29 @@ def _get_meaning(value_pb, is_list=False):
     :param is_list: Boolean indicating if the ``value_pb`` contains
                     a list value.
 
-    :rtype: int
+    :rtype: int | Tuple[Optional[int], Optional[list[int | None]]] | None
     :returns: The meaning for the ``value_pb`` if one is set, else
-              :data:`None`. For a list value, if there are disagreeing
-              means it just returns a list of meanings. If all the
-              list meanings agree, it just condenses them.
+              :data:`None`. For a list value, returns a tuple of
+              the root meaning of the list, and a list of meanings
+              of each sub-value. If subvalues are all empty, returns
+              :data:`None` instead of a list.
     """
     if is_list:
+        root_meaning = value_pb.meaning or None
         values = value_pb.array_value.values
 
-        # An empty list will have no values, hence no shared meaning
-        # set among them.
-        if len(values) == 0:
-            return None
-
         # We check among all the meanings, some of which may be None,
         # the rest which may be enum/int values.
-        all_meanings = [_get_meaning(sub_value_pb) for sub_value_pb in values]
-        unique_meanings = set(all_meanings)
-
-        if len(unique_meanings) == 1:
-            # If there is a unique meaning, we preserve it.
-            return unique_meanings.pop()
-        else:  # We know len(value_pb.array_value.values) > 0.
-            # If the meaning is not unique, just return all of them.
-            return all_meanings
-
-    elif value_pb.meaning:  # Simple field (int32).
-        return value_pb.meaning
-
-    return None
+        sub_meanings = [sub_value_pb.meaning or None for sub_value_pb in values]
+        if not any(meaning is not None for meaning in sub_meanings):
+            sub_meanings = None
+        if root_meaning is None and sub_meanings is None:
+            # no meanings to save
+            return None
+        else:
+            return root_meaning, sub_meanings
+    else:
+        return value_pb.meaning or None
 
 
 def _new_value_pb(entity_pb, name):
@@ -156,6 +148,10 @@ def entity_from_protobuf(pb):
 def _set_pb_meaning_from_entity(entity, name, value, value_pb, is_list=False):
     """Add meaning information (from an entity) to a protobuf.
 
+    value_pb is assumed to have no `meaning` data currently present.
+    This means if the entity's meaning data is None, this function will do nothing,
+    rather than removing any existing data.
+
     :type entity: :class:`google.cloud.datastore.entity.Entity`
     :param entity: The entity to be turned into a protobuf.
 
@@ -181,14 +177,20 @@ def _set_pb_meaning_from_entity(entity, name, value, value_pb, is_list=False):
     if orig_value is not value:
         return
 
-    # For lists, we set meaning on each sub-element.
-    if is_list:
-        if not isinstance(meaning, list):
-            meaning = itertools.repeat(meaning)
-        val_iter = zip(value_pb.array_value.values, meaning)
-        for sub_value_pb, sub_meaning in val_iter:
-            if sub_meaning is not None:
-                sub_value_pb.meaning = sub_meaning
+    if meaning is None:
+        # no meaning data to set
+        return
+    elif is_list:
+        # for lists, set meaning on the root pb and on each sub-element
+        root_meaning, sub_meaning_list = meaning
+        if root_meaning is not None:
+            value_pb.meaning = root_meaning
+        if sub_meaning_list:
+            for sub_value_pb, sub_meaning in zip(
+                value_pb.array_value.values, sub_meaning_list
+            ):
+                if sub_meaning is not None:
+                    sub_value_pb.meaning = sub_meaning
     else:
         value_pb.meaning = meaning
 

tests/unit/test_helpers.py

@@ -361,19 +361,21 @@ def test_entity_to_protobuf_w_variable_meanings():
     entity = Entity()
     name = "quux"
     entity[name] = values = [1, 20, 300]
-    meaning = 9
-    entity._meanings[name] = ([None, meaning, None], values)
+    root_meaning = 31
+    sub_meaning = 9
+    entity._meanings[name] = ((root_meaning, [None, sub_meaning, None]), values)
     entity_pb = entity_to_protobuf(entity)
 
     # Construct the expected protobuf.
     expected_pb = entity_pb2.Entity()
     value_pb = _new_value_pb(expected_pb, name)
+    value_pb.meaning = root_meaning
     value0 = value_pb.array_value.values.add()
     value0.integer_value = values[0]
     # The only array entry with a meaning is the middle one.
     value1 = value_pb.array_value.values.add()
     value1.integer_value = values[1]
-    value1.meaning = meaning
+    value1.meaning = sub_meaning
     value2 = value_pb.array_value.values.add()
     value2.integer_value = values[2]
 
@@ -1179,7 +1181,46 @@ def test__get_meaning_w_array_value():
     sub_value_pb2.string_value = "bye"
 
     result = _get_meaning(value_pb, is_list=True)
-    assert meaning == result
+    # should preserve sub-value meanings as list
+    assert (None, [meaning, meaning]) == result
+
+
+def test__get_meaning_w_array_value_root_meaning():
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import _get_meaning
+
+    value_pb = entity_pb2.Value()
+    meaning = 9
+    value_pb.meaning = meaning
+    sub_value_pb1 = value_pb._pb.array_value.values.add()
+    sub_value_pb2 = value_pb._pb.array_value.values.add()
+
+    sub_value_pb1.string_value = "hi"
+    sub_value_pb2.string_value = "bye"
+
+    result = _get_meaning(value_pb, is_list=True)
+    # should preserve sub-value meanings as list
+    assert (meaning, None) == result
+
+
+def test__get_meaning_w_array_value_root_and_sub_meanings():
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import _get_meaning
+
+    value_pb = entity_pb2.Value()
+    root_meaning = 9
+    sub_meaning = 3
+    value_pb.meaning = root_meaning
+    sub_value_pb1 = value_pb._pb.array_value.values.add()
+    sub_value_pb2 = value_pb._pb.array_value.values.add()
+
+    sub_value_pb1.meaning = sub_value_pb2.meaning = sub_meaning
+    sub_value_pb1.string_value = "hi"
+    sub_value_pb2.string_value = "bye"
+
+    result = _get_meaning(value_pb, is_list=True)
+    # should preserve sub-value meanings as list
+    assert (root_meaning, [sub_meaning, sub_meaning]) == result
 
 
 def test__get_meaning_w_array_value_multiple_meanings():
@@ -1198,7 +1239,7 @@ def test__get_meaning_w_array_value_multiple_meanings():
     sub_value_pb2.string_value = "bye"
 
     result = _get_meaning(value_pb, is_list=True)
-    assert result == [meaning1, meaning2]
+    assert result == (None, [meaning1, meaning2])
 
 
 def test__get_meaning_w_array_value_meaning_partially_unset():
@@ -1215,7 +1256,102 @@ def test__get_meaning_w_array_value_meaning_partially_unset():
     sub_value_pb2.string_value = "bye"
 
     result = _get_meaning(value_pb, is_list=True)
-    assert result == [meaning1, None]
+    assert result == (None, [meaning1, None])
+
+
+def test__get_meaning_w_array_value_meaning_fully_unset():
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import _get_meaning
+
+    value_pb = entity_pb2.Value()
+    sub_value_pb1 = value_pb._pb.array_value.values.add()
+    sub_value_pb2 = value_pb._pb.array_value.values.add()
+
+    sub_value_pb1.string_value = "hi"
+    sub_value_pb2.string_value = "bye"
+
+    result = _get_meaning(value_pb, is_list=True)
+    assert result is None
+
+
+@pytest.mark.parametrize("orig_root_meaning", [0, 1])
+@pytest.mark.parametrize("orig_sub_meaning", [0, 1])
+def test__set_pb_meaning_w_array_value_fully_unset(orig_root_meaning, orig_sub_meaning):
+    """
+    call _set_pb_meaning_from_entity with meaning=None data.
+    Should not touch proto's meaning field
+    """
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import _set_pb_meaning_from_entity
+    from google.cloud.datastore.entity import Entity
+
+    orig_pb = entity_pb2.Entity()
+    value_pb = orig_pb._pb.properties.get_or_create("value")
+    value_pb.meaning = orig_root_meaning
+    sub_value_pb1 = value_pb.array_value.values.add()
+    sub_value_pb1.meaning = orig_sub_meaning
+
+    entity = Entity(key="key")
+    entity._meanings = {"value": ((None, None), None)}
+    _set_pb_meaning_from_entity(entity, "value", None, value_pb, is_list=True)
+    assert value_pb.meaning == orig_root_meaning
+    assert value_pb.array_value.values[0].meaning == orig_sub_meaning
+
+
+@pytest.mark.parametrize("orig_meaning", [0, 1])
+def test__set_pb_meaning_w_value_unset(orig_meaning):
+    """
+    call _set_pb_meaning_from_entity with meaning=None data.
+    Should not touch proto's meaning field
+    """
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import _set_pb_meaning_from_entity
+    from google.cloud.datastore.entity import Entity
+
+    orig_pb = entity_pb2.Entity()
+    value_pb = orig_pb._pb.properties.get_or_create("value")
+    value_pb.meaning = orig_meaning
+
+    entity = Entity(key="key")
+    entity._meanings = {"value": (None, None)}
+    _set_pb_meaning_from_entity(entity, "value", None, value_pb, is_list=False)
+    assert value_pb.meaning == orig_meaning
+
+
+def test__array_w_meaning_end_to_end():
+    """
+    Test proto->entity->proto with an array with a meaning field
+    """
+    from google.cloud.datastore_v1.types import entity as entity_pb2
+    from google.cloud.datastore.helpers import entity_from_protobuf
+    from google.cloud.datastore.helpers import entity_to_protobuf
+
+    orig_pb = entity_pb2.Entity()
+    value_pb = orig_pb._pb.properties.get_or_create("value")
+    value_pb.meaning = 31
+    sub_value_pb1 = value_pb.array_value.values.add()
+    sub_value_pb1.double_value = 1
+    sub_value_pb1.meaning = 1
+    sub_value_pb2 = value_pb.array_value.values.add()
+    sub_value_pb2.double_value = 2
+    sub_value_pb3 = value_pb.array_value.values.add()
+    sub_value_pb3.double_value = 3
+    sub_value_pb3.meaning = 3
+    # convert to entity
+    entity = entity_from_protobuf(orig_pb._pb)
+    assert entity._meanings["value"][0] == (31, [1, None, 3])
+    assert entity._meanings["value"][1] == [1, 2, 3]
+    # convert back to pb
+    output_entity_pb = entity_to_protobuf(entity)
+    final_pb = output_entity_pb._pb.properties["value"]
+    assert final_pb.meaning == 31
+    assert len(final_pb.array_value.values) == 3
+    assert final_pb.array_value.values[0].meaning == 1
+    assert final_pb.array_value.values[0].double_value == 1
+    assert final_pb.array_value.values[1].meaning == 0
+    assert final_pb.array_value.values[1].double_value == 2
+    assert final_pb.array_value.values[2].meaning == 3
+    assert final_pb.array_value.values[2].double_value == 3
 
 
 def _make_geopoint(*args, **kwargs):