fix: check for legacy local structured property values (#365)

* fix: check for legacy local structured property values when converting from base type
refs #359

* fix: avoid compressing and immediately decompressing text property value when converting

Author: cguardia

packages/google-cloud-ndb/google/cloud/ndb/model.py

@@ -2494,9 +2494,14 @@ def _from_base_type(self, value):
             indicate that the value didn't need to be unwrapped and
             decompressed.
         """
+        # First, check for legacy compressed LocalStructuredProperty values.
+        # See https://github.com/googleapis/python-ndb/issues/359
+        if self._compressed and isinstance(value, ds_entity_module.Entity):
+            return
+
         if self._compressed and not isinstance(value, _CompressedValue):
             if not value.startswith(_ZLIB_COMPRESSION_MARKER):
-                value = zlib.compress(value)
+                return value
             value = _CompressedValue(value)
 
         if isinstance(value, _CompressedValue):

packages/google-cloud-ndb/tests/system/test_crud.py

@@ -421,6 +421,28 @@ class House(ndb.Model):
     assert retrieved.dogs == dogs
 
 
+def test_get_by_id_with_compressed_repeated_local_structured_property(
+    client_context, dispose_of, ds_client
+):
+    class Dog(ndb.Model):
+        name = ndb.TextProperty()
+
+    class House(ndb.Model):
+        dogs = ndb.LocalStructuredProperty(Dog, repeated=True, compressed=True)
+
+    with client_context.new(legacy_data=True).use():
+        entity = House()
+        dogs = [Dog(name="Mika"), Dog(name="Mocha")]
+        entity.dogs = dogs
+
+        key = entity.put()
+        house_id = key.id()
+        dispose_of(key._key)
+
+        retrieved = House.get_by_id(house_id)
+        assert retrieved.dogs == dogs
+
+
 @pytest.mark.usefixtures("client_context")
 def test_retrieve_entity_with_legacy_compressed_property(
     ds_entity_with_meanings,

packages/google-cloud-ndb/tests/unit/test_model.py

@@ -3744,6 +3744,18 @@ class SomeKind(model.Model):
             ds_entity = model._entity_to_ds_entity(entity.foo, set_key=False)
             assert data == {"foo": ds_entity}
 
+    @staticmethod
+    def test_legacy_repeated_compressed_local_structured_property():
+        class SubKind(model.Model):
+            bar = model.TextProperty()
+
+        prop = model.LocalStructuredProperty(
+            SubKind, repeated=True, compressed=True
+        )
+        entity = SubKind(bar="baz")
+        ds_entity = model._entity_to_ds_entity(entity, set_key=False)
+        assert prop._call_from_base_type(ds_entity) == entity
+
 
 class TestGenericProperty:
     @staticmethod