[#9407]Enable Firestore data bundle to support empty array (#9467)

* Change the require condition to optional in some data bundle decode functions

Author: cherylEnkidu

Firestore/core/src/bundle/bundle_serializer.cc

@@ -7,7 +7,7 @@
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
- * Unless Requiredd by applicable law or agreed to in writing, software
+ * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
@@ -393,6 +393,16 @@ const nlohmann::json& JsonReader::RequiredObject(const char* child_name,
   return json_object.at(child_name);
 }
 
+const nlohmann::json& JsonReader::OptionalObject(
+    const char* child_name,
+    const json& json_object,
+    const nlohmann::json& default_value) {
+  if (json_object.contains(child_name)) {
+    return json_object.at(child_name);
+  }
+  return default_value;
+}
+
 double JsonReader::RequiredDouble(const char* name, const json& json_object) {
   if (json_object.contains(name)) {
     double result = DecodeDouble(json_object.at(name));
@@ -614,11 +624,22 @@ FilterList BundleSerializer::DecodeCompositeFilter(JsonReader& reader,
     return {};
   }
 
-  auto filters = reader.RequiredArray("filters", filter);
+  const std::vector<json> default_filters;
+  const auto& filters =
+      reader.OptionalArray("filters", filter, default_filters);
+
+  const json default_objects;
   FilterList result;
   for (const auto& f : filters) {
-    result = result.push_back(
-        DecodeFieldFilter(reader, reader.RequiredObject("fieldFilter", f)));
+    const json& field_filter =
+        reader.OptionalObject("fieldFilter", f, default_objects);
+    if (!field_filter.empty()) {
+      result = result.push_back(DecodeFieldFilter(reader, field_filter));
+    } else {
+      result = result.push_back(DecodeUnaryFilter(
+          reader, reader.OptionalObject("unaryFilter", f, default_objects)));
+    }
+
     if (!reader.ok()) {
       return {};
     }
@@ -636,8 +657,10 @@ Bound BundleSerializer::DecodeBound(JsonReader& reader,
     return default_bound;
   }
 
+  std::vector<json> default_values;
   const json& bound_json = reader.RequiredObject(bound_name, query);
-  std::vector<json> values = reader.RequiredArray("values", bound_json);
+  std::vector<json> values =
+      reader.OptionalArray("values", bound_json, default_values);
   bool before = reader.OptionalBool("before", bound_json);
 
   auto positions = MakeSharedMessage<google_firestore_v1_ArrayValue>({});
@@ -737,7 +760,9 @@ Message<google_firestore_v1_MapValue> BundleSerializer::DecodeMapValue(
 
 Message<google_firestore_v1_ArrayValue> BundleSerializer::DecodeArrayValue(
     JsonReader& reader, const json& array_json) const {
-  const auto& values = reader.RequiredArray("values", array_json);
+  std::vector<json> default_values;
+  const auto& values =
+      reader.OptionalArray("values", array_json, default_values);
 
   Message<google_firestore_v1_ArrayValue> array_value;
   SetRepeatedField(

Firestore/core/src/bundle/bundle_serializer.h

@@ -64,8 +64,12 @@ class JsonReader : public util::ReadContext {
       const char* name,
       const nlohmann::json& json_object,
       const std::vector<nlohmann::json>& default_value);
+
   const nlohmann::json& RequiredObject(const char* child_name,
                                        const nlohmann::json& json_object);
+  const nlohmann::json& OptionalObject(const char* child_name,
+                                       const nlohmann::json& json_object,
+                                       const nlohmann::json& default_value);
 
   double RequiredDouble(const char* name, const nlohmann::json& json_object);
   double OptionalDouble(const char* name,

Firestore/core/test/unit/bundle/bundle_reader_test.cc

@@ -229,9 +229,12 @@ class BundleReaderTest : public ::testing::Test {
     value2.set_string_value("okok");
     ProtoValue value3;
     value3.set_null_value(google::protobuf::NULL_VALUE);
+    ProtoValue value4;
+    value4.mutable_array_value();
     document.mutable_fields()->insert({"\0\ud7ff\ue000\uffff\"", value1});
     document.mutable_fields()->insert({"\"(╯°□°）╯︵ ┻━┻\"", value2});
     document.mutable_fields()->insert({"nValue", value3});
+    document.mutable_fields()->insert({"emptyArray", value4});
 
     return document;
   }

Firestore/core/test/unit/bundle/bundle_serializer_test.cc

@@ -826,14 +826,6 @@ TEST_F(BundleSerializerTest, DecodeInvalidFieldFilterOperatorFails) {
     EXPECT_NOT_OK(reader.status());
   }
 
-  {
-    auto json_copy =
-        ReplacedCopy(json_string, "\"stringValue\"", "\"arrayValue\"");
-    JsonReader reader;
-    bundle_serializer.DecodeNamedQuery(reader, Parse(json_copy));
-    EXPECT_NOT_OK(reader.status());
-  }
-
   {
     auto json_copy = ReplacedCopy(json_string, "\"op\"", "\"Op\"");
     JsonReader reader;
@@ -850,6 +842,14 @@ TEST_F(BundleSerializerTest, DecodeInvalidFieldFilterOperatorFails) {
 }
 
 TEST_F(BundleSerializerTest, DecodesCompositeFilter) {
+  core::Query original = testutil::Query("colls")
+                             .AddingFilter(Filter("f1", "==", nullptr))
+                             .AddingFilter(Filter("f2", "==", true))
+                             .AddingFilter(Filter("f3", "==", 50.3));
+  VerifyNamedQueryRoundtrip(original);
+}
+
+TEST_F(BundleSerializerTest, DecodesCompositeNotNullFilter) {
   core::Query original =
       testutil::Query("colls")
           .AddingFilter(Filter("f1", "not-in", Array(1, "2", 3.0)))
@@ -858,6 +858,13 @@ TEST_F(BundleSerializerTest, DecodesCompositeFilter) {
   VerifyNamedQueryRoundtrip(original);
 }
 
+TEST_F(BundleSerializerTest, DecodesCompositeNullFilter) {
+  core::Query original = testutil::Query("colls")
+                             .AddingFilter(Filter("f1", "==", nullptr))
+                             .AddingFilter(Filter("f2", "==", nullptr));
+  VerifyNamedQueryRoundtrip(original);
+}
+
 TEST_F(BundleSerializerTest, DecodeInvalidCompositeFilterOperatorFails) {
   std::string json_string = NamedQueryJsonString(
       testutil::Query("colls")