[Sync] Add support for retrying a getupdates due to a context change

We detect a context conflict using the version value, and if detected force the
getupdates to retry.

BUG=360280

Review URL: https://codereview.chromium.org/232003005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263134 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 86 insertions, 5 deletions

diff --git a/sync/engine/directory_update_handler_unittest.cc b/sync/engine/directory_update_handler_unittest.cc
index 6d1b35a..ec8cc35 100644
--- a/sync/engine/directory_update_handler_unittest.cc
+++ b/sync/engine/directory_update_handler_unittest.cc
@@ -195,14 +195,14 @@ TEST_F(DirectoryUpdateHandlerProcessUpdateTest,
 
 // Test the receipt of a non-bookmark item.
 TEST_F(DirectoryUpdateHandlerProcessUpdateTest, ReceiveNonBookmarkItem) {
-  DirectoryUpdateHandler handler(dir(), PREFERENCES, ui_worker());
+  DirectoryUpdateHandler handler(dir(), AUTOFILL, ui_worker());
   sync_pb::GetUpdatesResponse gu_response;
   sessions::StatusController status;
 
   std::string root = syncable::GetNullId().GetServerId();
   syncable::Id server_id = syncable::Id::CreateFromServerId("xyz");
   scoped_ptr<sync_pb::SyncEntity> e =
-      CreateUpdate(SyncableIdToProto(server_id), root, PREFERENCES);
+      CreateUpdate(SyncableIdToProto(server_id), root, AUTOFILL);
   e->set_server_defined_unique_tag("9PGRuKdX5sHyGMB17CvYTXuC43I=");
 
   // Add it to the applicable updates list.
@@ -283,7 +283,9 @@ TEST_F(DirectoryUpdateHandlerProcessUpdateTest, GarbageCollectionByVersion) {
   updates.push_back(e2.get());
 
   // Process and apply updates.
-  handler.ProcessGetUpdatesResponse(progress, context, updates, &status);
+  EXPECT_EQ(
+      SYNCER_OK,
+      handler.ProcessGetUpdatesResponse(progress, context, updates, &status));
   handler.ApplyUpdates(&status);
 
   // Verify none is deleted because they are unapplied during GC.
@@ -293,14 +295,93 @@ TEST_F(DirectoryUpdateHandlerProcessUpdateTest, GarbageCollectionByVersion) {
 
   // Process and apply again. Old entry is deleted but not root.
   progress.mutable_gc_directive()->set_version_watermark(kDefaultVersion + 20);
-  handler.ProcessGetUpdatesResponse(
-      progress, context, SyncEntityList(), &status);
+  EXPECT_EQ(SYNCER_OK,
+            handler.ProcessGetUpdatesResponse(
+                progress, context, SyncEntityList(), &status));
   handler.ApplyUpdates(&status);
   EXPECT_TRUE(EntryExists(type_root->id_string()));
   EXPECT_FALSE(EntryExists(e1->id_string()));
   EXPECT_TRUE(EntryExists(e2->id_string()));
 }
 
+TEST_F(DirectoryUpdateHandlerProcessUpdateTest, ContextVersion) {
+  DirectoryUpdateHandler handler(dir(), SYNCED_NOTIFICATIONS, ui_worker());
+  sessions::StatusController status;
+  int field_number = GetSpecificsFieldNumberFromModelType(SYNCED_NOTIFICATIONS);
+
+  sync_pb::DataTypeProgressMarker progress;
+  progress.set_data_type_id(
+      GetSpecificsFieldNumberFromModelType(SYNCED_NOTIFICATIONS));
+  progress.set_token("token");
+
+  sync_pb::DataTypeContext old_context;
+  old_context.set_version(1);
+  old_context.set_context("data");
+  old_context.set_data_type_id(field_number);
+
+  scoped_ptr<sync_pb::SyncEntity> type_root =
+      CreateUpdate(SyncableIdToProto(syncable::Id::CreateFromServerId("root")),
+                   syncable::GetNullId().GetServerId(),
+                   SYNCED_NOTIFICATIONS);
+  type_root->set_server_defined_unique_tag(
+      ModelTypeToRootTag(SYNCED_NOTIFICATIONS));
+  type_root->set_folder(true);
+  scoped_ptr<sync_pb::SyncEntity> e1 =
+      CreateUpdate(SyncableIdToProto(syncable::Id::CreateFromServerId("e1")),
+                   type_root->id_string(),
+                   SYNCED_NOTIFICATIONS);
+
+  SyncEntityList updates;
+  updates.push_back(type_root.get());
+  updates.push_back(e1.get());
+
+  // The first response should be processed fine.
+  EXPECT_EQ(SYNCER_OK,
+            handler.ProcessGetUpdatesResponse(
+                progress, old_context, updates, &status));
+  handler.ApplyUpdates(&status);
+
+  EXPECT_TRUE(EntryExists(type_root->id_string()));
+  EXPECT_TRUE(EntryExists(e1->id_string()));
+
+  {
+    sync_pb::DataTypeContext dir_context;
+    syncable::ReadTransaction trans(FROM_HERE, dir());
+    trans.directory()->GetDataTypeContext(
+        &trans, SYNCED_NOTIFICATIONS, &dir_context);
+    EXPECT_EQ(old_context.SerializeAsString(), dir_context.SerializeAsString());
+  }
+
+  sync_pb::DataTypeContext new_context;
+  new_context.set_version(0);
+  new_context.set_context("old");
+  new_context.set_data_type_id(field_number);
+
+  scoped_ptr<sync_pb::SyncEntity> e2 =
+      CreateUpdate(SyncableIdToProto(syncable::Id::CreateFromServerId("e2")),
+                   type_root->id_string(),
+                   SYNCED_NOTIFICATIONS);
+  updates.clear();
+  updates.push_back(e2.get());
+
+  // The second response, with an old context version, should result in an
+  // error and the updates should be dropped.
+  EXPECT_EQ(DATATYPE_TRIGGERED_RETRY,
+            handler.ProcessGetUpdatesResponse(
+                progress, new_context, updates, &status));
+  handler.ApplyUpdates(&status);
+
+  EXPECT_FALSE(EntryExists(e2->id_string()));
+
+  {
+    sync_pb::DataTypeContext dir_context;
+    syncable::ReadTransaction trans(FROM_HERE, dir());
+    trans.directory()->GetDataTypeContext(
+        &trans, SYNCED_NOTIFICATIONS, &dir_context);
+    EXPECT_EQ(old_context.SerializeAsString(), dir_context.SerializeAsString());
+  }
+}
+
 // A test harness for tests that focus on applying updates.
 //
 // Update application is performed when we want to take updates that were