LcmToMongo action now supports incomplete DB's.

This fixes an exception thrown when trying to deserialize OptionListItem's with partial DB entries. For initial clones, the DB is somewhat filled out (why?), so this adds a try/catch to allow the DB request to fail, in which case an empty LF list will be used.

Also had to change slightly the UpdateRecord call of MongoConnection from using FindOneAndUpdate to UpdateOne. It appeared the only difference was the return type, which was unused, and the former was deserializing its target type before serializing it, causing the same DB exception.

src/LfMerge.Core/DataConverters/ConvertLcmToMongoLexicon.cs

@@ -624,11 +624,23 @@ private Dictionary<string, LfInputSystemRecord> LcmWsToLfWs()
 			return lfWsList;
 		}
 
-		private ConvertLcmToMongoOptionList ConvertOptionListFromLcm(ILfProject project, string listCode, ICmPossibilityList LcmOptionList, bool updateMongoList = true)
+		private ConvertLcmToMongoOptionList ConvertOptionListFromLcm(ILfProject project, string listCode, ICmPossibilityList lcmOptionList, bool updateMongoList = true)
 		{
-			LfOptionList lfExistingOptionList = Connection.GetLfOptionListByCode(project, listCode);
+			LfOptionList lfExistingOptionList = null;
+			try
+			{
+				lfExistingOptionList = Connection.GetLfOptionListByCode(project, listCode); //doesn't work unless the DB is fully populated
+			}
+			catch (Exception) { }
+
 			var converter = new ConvertLcmToMongoOptionList(lfExistingOptionList, _wsEn, listCode, Logger, ServiceLocator.WritingSystemFactory);
-			LfOptionList lfChangedOptionList = converter.PrepareOptionListUpdate(LcmOptionList);
+			LfOptionList lfChangedOptionList = converter.PrepareOptionListUpdate(lcmOptionList);
+
+			if (lfExistingOptionList == null)
+			{
+				lfChangedOptionList.DateModified = lcmOptionList.DateModified; //if DB didn't have an entry, preserve LCM date
+			}
+
 			if (updateMongoList)
 				Connection.UpdateRecord(project, lfChangedOptionList, listCode);
 			return new ConvertLcmToMongoOptionList(lfChangedOptionList, _wsEn, listCode, Logger, ServiceLocator.WritingSystemFactory);

src/LfMerge.Core/MongoConnector/MongoConnection.cs

@@ -970,10 +970,10 @@ private bool UpdateRecordImpl<TDocument>(ILfProject project, TDocument data, Fil
 				mongoDb = GetMainDatabase();
 			UpdateDefinition<TDocument> update = BuildUpdate(data, false);
 			IMongoCollection<TDocument> collection = mongoDb.GetCollection<TDocument>(collectionName);
-			var updateOptions = new FindOneAndUpdateOptions<TDocument> {
+			var updateOptions = new UpdateOptions {
 				IsUpsert = true
 			};
-			collection.FindOneAndUpdate(filter, update, updateOptions);
+			collection.UpdateOne(filter, update, updateOptions);
 			return true;
 		}