Possible mergeable classes for merging code bases

[DavoudEshtehari]

The main aim of this ticket is to clarify the project progress and having contribution with who is interested in it.

At the first step, we've prepared a list of possible mergeable files with their types which maybe need some pruning. Then, priority could be declared before starting to merge.

Mergable files list

File & PR	Type	Group	Priority
DbConnectionStringCommon.cs #1265	DbConnectionStringDefaults DbConnectionStringKeywords DbConnectionStringSynonyms DbConnectionStringBuilderUtil	Common	1
DbConnectionOptions.Common.cs (core) DbConnectionOptions.cs #1279	DbConnectionOptions KEY SYNONYM	Common	1
AdapterUtil.cs AdapterUtil.Drivers.cs (core) AdapterUtil.SqlClient.cs (core) #1306	ADP	Common	1
StringsHelper.cs #1288	StringsHelper	Common	1
DbConnectionClosed.cs	DbConnectionClosed DbConnectionBusy DbConnectionClosedBusy DbConnectionClosedConnecting DbConnectionClosedNeverOpened DbConnectionClosedPreviouslyOpened DbConnectionOpenBusy	ProviderBase
DbConnectionInternal.cs	DbConnectionInternal	ProviderBase
DbConnectionFactory.cs	DbConnectionFactory	ProviderBase
DbConnectionPool.cs #2812	PendingGetConnection PoolWaitHandles State TransactedConnectionList TransactedConnectionPool	ProviderBase
DbConnectionPoolGroup.cs #1371	DbConnectionPoolGroup	ProviderBase
DbConnectionPoolIdentity.cs DbConnectionPoolIdentity.Unix.cs (core) DbConnectionPoolIdentity.Windows.cs (core)	DbConnectionPoolIdentity	ProviderBase
DbMetaDataFactory.cs #1278	DbMetaDataFactory	ProviderBase
DbReferenceCollection.cs #2403	DbReferenceCollection CollectionEntry	ProviderBase
TimeoutTimer.cs #1273	TimeoutTimer	ProviderBase
SQLResource.cs #1276	SQLResource	SqlTypes
SqlFileStream.cs (fx) SqlFileStream.Windows.cs (core)	SqlFileStream	SqlTypes
MetadataUtilsSmi.cs #1339	MetadataUtilsSmi	SqlClient.Server
SmiEventSink.cs #1324	SmiEventSink	SqlClient.Server
SmiEventSink_Default.cs #1324	SmiEventSink_Default	SqlClient.Server
SmiMetaDataProperty.cs #1320	SmiDefaultFieldsProperty SmiMetaDataProperty SmiMetaDataPropertyCollection SmiOrderProperty SmiPropertySelector SmiUniqueKeyProperty	SqlClient.Server
SmiTypedGetterSetter.cs #1321	SmiTypedGetterSetter	SqlClient.Server
SmiXetterAccessMap.cs #1310	SmiXetterAccessMap	SqlClient.Server
SqlDataRecord.cs #1309	SqlDataRecord	SqlClient.Server
SqlSer.cs #1313	BinarySerializeSerializer DummyStream NormalizedSerializer SerializationHelperSql9 Serializer	SqlClient.Server
ValueUtilsSmi.cs #1326	ValueUtilsSmi	SqlClient.Server
AlwaysEncryptedHelperClasses.cs (core) TdsParserHelperClasses.cs #2376	_SqlMetaData _SqlMetaDataSet _SqlMetaDataSetCollection _SqlRPC CallbackType EncryptionOptions PreLoginHandshakeStatus PreLoginOptions RunBehavior TdsParserState FederatedAuthenticationFeatureExtensionData SqlCollation RoutingInfo SqlEnvChange SqlLogin SqlLoginAck SqlFedAuthInfo SqlFedAuthToken SqlMetaDataPriv SqlMetaDataXmlSchemaCollection SqlMetaDataUdt SqlReturnValue MultiPartTableName SslProtocolsHelper	SqlClient
AlwaysEncryptedKeyConverter.Cng.cs (fx) AlwaysEncryptedKeyConverter.CrossPlatform.cs (core)	KeyConverter	SqlClient
LocalDBAPI.cs LocalDBAPI.Common.cs (core) LocalDBAPI.uap.cs (core) LocalDBAPI.Unix.cs (core) LocalDBAPI.Windows.cs (core)	LocalDBAPI	SqlClient
SimulatorEnclaveProvider.cs (fx) SimulatorEnclaveProvider.NetCoreApp.cs (core) #1419	SimulatorEnclaveProvider	SqlClient
SqlAuthenticationProviderManager.cs SqlAuthenticationProviderManager.NetCoreApp.cs (core) SqlAuthenticationProviderManager.NetStandard.cs (core)	SqlAuthenticationProviderManager SqlAuthenticationInitializer SqlAuthenticationProviderConfigurationSection SqlClientAuthenticationProviderConfigurationSection	SqlClient
SqlBuffer.cs #1438	SqlBuffer	SqlClient
SqlBulkCopy.cs	_ColumnMapping Row Result BulkCopySimpleResultSet SqlBulkCopy	SqlClient
SqlBulkCopyColumnMappingCollection.cs #1285	SqlBulkCopyColumnMappingCollection	SqlClient
SqlCachedBuffer.cs #1280	SqlCachedBuffer	SqlClient
SqlClientFactory.cs #2369	SqlClientFactory	SqlClient
SqlClientMetaDataCollectionNames.cs #1287	SqlClientMetaDataCollectionNames	SqlClient
SqlColumnEncryptionCertificateStoreProvider.Windows.cs (core) SqlColumnEncryptionCertificateStoreProvider.cs (fx) SqlColumnEncryptionCertificateStoreProvider.Unix.cs (core)	SqlColumnEncryptionCertificateStoreProvider	SqlClient
SqlColumnEncryptionCngProvider.cs (fx) SqlColumnEncryptionCngProvider.Windows.cs (core) SqlColumnEncryptionCngProvider.Unix.cs (core)	SqlColumnEncryptionCngProvider #2501	SqlClient
SqlColumnEncryptionCspProvider.cs (fx) SqlColumnEncryptionCspProvider.Windows.cs (core) SqlColumnEncryptionCspProvider.Unix.cs (core)	SqlColumnEncryptionCspProvider	SqlClient
SqlColumnEncryptionEnclaveProvider.cs SqlColumnEncryptionEnclaveProvider.NetCoreApp.cs (core)	SqlColumnEncryptionEnclaveProvider	SqlClient
SqlCommand.cs	SqlCommand	SqlClient
SqlCommandBuilder.cs #1284	SqlCommandBuilder	SqlClient
SqlCommandSet.cs #1286	SqlCommandSet	SqlClient
SqlConnection.cs SqlConnectionHelper.cs	SqlConnection	SqlClient
SqlConnectionFactory.cs SqlConnectionFactory.AssemblyLoadContext.cs (core)	SqlConnectionFactory	SqlClient
SqlConnectionPoolGroupProviderInfo.cs #1323	SqlConnectionPoolGroupProviderInfo	SqlClient
SqlConnectionPoolKey.cs #1292	SqlConnectionPoolKey	SqlClient
SqlConnectionString.cs #1329 #1359	DEFAULT KEY SYNONYM TYPESYSTEMVERSION TRANSACTIONBINDING	SqlClient	1
SqlConnectionString.cs SqlConnectionString.NetCoreApp.cs (core) #1329 #1359	SqlConnectionString	SqlClient
SqlConnectionStringBuilder.cs #1349	SqlConnectionStringBuilder	SqlClient
SqlDataAdapter.cs #1295	SqlDataAdapter
SqlDataReader.cs #1309	SqlDataReader	SqlClient
SqlDelegatedTransaction.cs SqlDelegatedTransaction.NetCoreApp.cs (core) SqlDelegatedTransaction.NetStandard.cs (core)	SqlDelegatedTransaction #2861	SqlClient
SqlDependency.cs #1299	SqlDependency	SqlClient
SqlDependencyListener.cs #1308	SqlDependencyProcessDispatcher	SqlClient
SqlDependencyUtils.cs #1370 #2812 SqlDependencyUtils.AppDomain.cs (core) SqlDependencyUtils.AssemblyLoadContext.cs (core)	SqlDependencyPerAppDomainDispatcher	SqlClient
SqlEnums.cs #1317	MetaType TdsDateTime	SqlClient
SqlError.cs #1322	SqlError	SqlClient
SqlErrorCollection.cs #1305	SqlErrorCollection	SqlClient
SqlException.cs #1300	SqlException	SqlClient
SqlInfoMessageEvent.cs #1311	SqlInfoMessageEventArgs	SqlClient
SqlInternalConnection.cs #1598	SqlInternalConnection	SqlClient
SqlInternalConnectionTds.cs	SqlInternalConnectionTds SessionStateRecord SessionData ServerInfo	SqlClient
SqlInternalTransaction.cs #1346	SqlInternalTransaction	SqlClient
Sqlmetadatafactory.cs #1315	sqlmetadatafactory	SqlClient
SqlNotificationEventArgs.cs #1314	SqlNotificationEventArgs	SqlClient
SqlParameter.cs #1354	DataFeed StreamDataFeed TextDataFeed XmlDataFeed SqlParameter	SqlClient
SqlQueryMetadataCache.cs #1316	SqlQueryMetadataCache	SqlClient
SqlReferenceCollection.cs #1303	SqlReferenceCollection	SqlClient
SqlSequentialStream.cs #1345	SqlSequentialStream	SqlClient
SqlSequentialTextReader.cs #1343	SqlSequentialTextReader SqlUnicodeEncoding	SqlClient
SqlStream.cs #1337	SqlStream SqlCachedStream SqlStreamingXml	SqlClient
SqlTransaction.cs #1353	SqlTransaction	SqlClient
SqlUtil.cs #2503 #2533	AsyncHelper SQL SQLMessage SqlServerEscapeHelper SysTxForGlobalTransactions	SqlClient
TdsEnums.cs #1369	TdsEnums ActiveDirectoryAuthentication ParsingErrorState SniContext SqlConnectionColumnEncryptionSetting SqlConnectionOverrides SqlCommandColumnEncryptionSetting SqlConnectionAttestationProtocol SqlConnectionIPAddressPreference SqlAuthenticationMethod TransparentNetworkResolutionState DescribeParameterEncryptionResultSet1 DescribeParameterEncryptionResultSet2 DescribeParameterEncryptionResultSet3	SqlClient
TdsParser.cs TdsParser.NetCoreApp.cs (core) TdsParser.NetStandard.cs (core) TdsParser.RegisterEncoding.cs (core) TdsParser.Unix.cs (core) TdsParser.Windows.cs (core)	TdsParser	SqlClient
TdsParserSafeHandles.cs #1604	SNILoadHandle SNIHandle SNIPacket WritePacketCache	SqlClient
TdsParserSessionPool.cs #1595	TdsParserSessionPool	SqlClient
TdsParserStateObject.cs #1520, #1844, #2168, #2254, #2302	TdsParserStateObject LastIOTimer	SqlClient
TdsParserStaticMethods.cs #1588 #2814	TdsParserStaticMethods	SqlClient
SqlFileStream.cs (fx) SqlFileStream.Windows.cs (core) #2398	SqlFileStream	SqlTypes

[Wraith2]

I think KeyConverter is done. There isn't a way to merge further for two reasons, 1) netstandard doesn't contain elliptical curve 2) netcore and netfx instantiate crypto providers in entirely different ways that I couldn't abstract any further.

SqlBuffer is very close to being done the remaining differences are because there is allocation free guid support in netcore that isn't in netfx. This means that SqlDataReader changes need to be ported to add that feature on netfx.

Some classes like TdsParser, TdsParserStateObject, SqlDataReader, SqlCommand are very large and I don't think we can do in a single PR, it would be impossible to review. I believe the way to do those types is a many small PR's which take identical functionality from both into a new shared version of the file slowly reducing each project specific file to the parts which are different and then those can be thoroughly reviewed.

[DavoudEshtehari]

Thanks for the comments.
Regarding the KeyConverter, I think we could extract the behavior of the class in the lowest possible abstraction.
I completely agree with keeping the PRs as simple as possible for the sake of review. Based on your idea, the above table doesn't mean each file or type should be merged in a single PR.

[Wraith2]

Looking at some of the merged from @lcheunglci I thought it might be useful to write down some of my knowledge and methodology used in my merges. From what I've gathered:

The nextfx codebase was forked at some point and that fork had a managed implementation of the network interface written so that it could be used on linux for netcore. This means that this codebase now has managed and native versions of the Sql Network Interface (SNI) in the netcore codebase and they are switched out depending on the platform that you restore the nuget package for. You can also force the use of managed network in windows with an appcontext switch. This mostly makes a difference in the core of TdsParser and TdsParserStateObject.

After netcore was forked the codebase was cleaned up a bit. So in general netcore is newer than netfx. However, changes and fixes may have been made to the netcore and netfx codebases independently so there's no guarantee that either was one better than the other they can both contain better versions of any particular function.

The netfx codebase is very very old, it was in the original 1.0 release of netfx and it hasn't always been updated to use the latest features. An example of this is the pool key derivation mechanism on netfx, it uses direct api calls to windows security apis because the managed equivalents were not available or not know to be usable at the time of writing.

This means that any change can be old or new and come from any version of the source code. To merge them you have to try to work out if they are functionally identical or equivalent enough that the difference cannot be observed by users up to and including timing and ordering of operations. This can get complicated and time consuming.

Style between the two codebases is highly variable. In general when merging a file it's a good idea to turn on the compiler Info messages and look through all the possible refactoring options is gives you. You don't have to take all the suggestions just take a look at them and make the code feel like it has the same style as some of the already merged components. The objective is to work towards a coherently styled single codebase where naming and formatting are easy to understand between most files.

[lcheunglci]

Thanks @Wraith2 for your insight. I'll keep that in mind when I'm doing the code base merges. I'm currently starting small particularly focusing on the simpler code merges with the least conflicts before I look at the bigger ones. Your feedback and suggestions are much appreciated.