fix: repeated structured property containing blob property with legac…

…y_data (#817) (#946)

* Fix issue 817

* Fix issue 817

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: venticello <omnisens@gmail.com>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Jim Morrison <phython@google.com>

google/cloud/ndb/model.py

@@ -2662,11 +2662,16 @@ def _to_datastore(self, entity, data, prefix="", repeated=False):
                 value = compressed_value
                 data[key] = value
             if not self._repeated:
-                if value and not value.startswith(_ZLIB_COMPRESSION_MARKERS):
-                    value = zlib.compress(value)
-                    data[key] = value
+                values = [
+                    zlib.compress(v)
+                    if v and not v.startswith(_ZLIB_COMPRESSION_MARKERS)
+                    else v
+                    for v in (value if repeated else [value])
+                ]
+                value = values if repeated else values[0]
+                data[key] = value
 
-            if value:
+            if value and not repeated:
                 data.setdefault("_meanings", {})[key] = (
                     _MEANING_COMPRESSED,
                     value,

tests/unit/test_model.py

@@ -1816,6 +1816,52 @@ class ThisKind(model.Model):
             compressed_value_two,
         ]
 
+    @staticmethod
+    def test__to_datastore_legacy_compressed_repeated_in_parent(in_context):
+        class ThisKind(model.Model):
+            bar = model.BlobProperty(compressed=True, repeated=False)
+
+        class ParentKind(model.Model):
+            foo = model.StructuredProperty(ThisKind, repeated=True)
+
+        with in_context.new(legacy_data=True).use():
+            uncompressed_value_one = b"abc" * 1000
+            compressed_value_one = zlib.compress(uncompressed_value_one)
+            uncompressed_value_two = b"xyz" * 1000
+            compressed_value_two = zlib.compress(uncompressed_value_two)
+            entity = ParentKind(
+                foo=[
+                    ThisKind(bar=uncompressed_value_one),
+                    ThisKind(bar=uncompressed_value_two),
+                ]
+            )
+            ds_entity = model._entity_to_ds_entity(entity)
+            assert "foo.bar" not in ds_entity._meanings
+            assert "foo.bar" in ds_entity.keys()
+            assert ds_entity.get("foo.bar") == [
+                compressed_value_one,
+                compressed_value_two,
+            ]
+
+    @staticmethod
+    def test__to_datastore_legacy_compressed_repeated_in_parent_uninitialized(
+        in_context,
+    ):
+        class ThisKind(model.Model):
+            bar = model.BlobProperty(compressed=True, repeated=False)
+
+        class ParentKind(model.Model):
+            foo = model.StructuredProperty(ThisKind, repeated=True)
+
+        with in_context.new(legacy_data=True).use():
+            uncompressed_value = b"abc" * 1000
+            compressed_value = zlib.compress(uncompressed_value)
+            entity = ParentKind(foo=[ThisKind(), ThisKind(bar=uncompressed_value)])
+            ds_entity = model._entity_to_ds_entity(entity)
+            assert "foo.bar" not in ds_entity._meanings
+            assert "foo.bar" in ds_entity.keys()
+            assert ds_entity.get("foo.bar") == [None, compressed_value]
+
     @staticmethod
     @pytest.mark.usefixtures("in_context")
     def test__to_datastore_compressed_uninitialized():