fix(sync): robust change-tracking version handling (#100)

- Skip table and log when SourceVersion is null (LogUnknownSourceVersion)
- Treat "already up to date" by comparing CurrentVersion only
- Use GetSourceSelectAllStatement when TargetVersion.CurrentVersion < 0
  (was <= 1)
- GetTableVersionStatement: derive MinValidVersion from
  sys.change_tracking_tables for global CT
- Use collection expression in BulkCopyData; replace exceptions.Any()
  with exceptions.Count != 0

Author: devlead

src/SqlBulkSyncFunction/Helpers/SqlCommandExtensions.cs

@@ -92,8 +92,7 @@ public static void BulkCopyData(
         object scope,
         ILogger logger
         ) => Array.ForEach(
-            new[]
-            {
+            [
                 new
                 {
                     Name = tableSchema.SyncNewOrUpdatedTableName,
@@ -106,7 +105,7 @@ ILogger logger
                     SelectStatement = tableSchema.SourceDeletedSelectStatement,
                     Description = "deleted"
                 }
-            },
+            ],
             table =>
             {
                 using var sourceCmd = new SqlCommand

src/SqlBulkSyncFunction/Helpers/SqlStatementExtensions.cs

@@ -18,9 +18,12 @@ Column[] columns
                     SELECT  '{tableName}'                                       AS TableName,
                             CHANGE_TRACKING_CURRENT_VERSION()                   AS CurrentVersion,
                             CHANGE_TRACKING_MIN_VALID_VERSION(
-                                OBJECT_ID('{tableName}')
+                                    ctt.object_id
                             )                                                   AS MinValidVersion,
                             SYSDATETIMEOFFSET()                                 AS Queried
+
+                        FROM sys.change_tracking_tables AS ctt
+                        WHERE ctt.object_id = OBJECT_ID('{tableName}')
                     """;
         }
 
@@ -314,7 +317,7 @@ public static string GetNewOrUpdatedAtSourceSelectStatement(this TableSchema tab
                 );
         }
 
-        var statement = (tableSchema.TargetVersion.CurrentVersion <= 1)
+        var statement = (tableSchema.TargetVersion.CurrentVersion < 0)
             ? tableSchema.GetSourceSelectAllStatement()
             : string.Format(
                 """

src/SqlBulkSyncFunction/Services/ProcessSyncJobService.cs

@@ -73,7 +73,12 @@ public async Task ProcessSyncJob(SyncJob syncJob, bool globalChangeTracking)
                             {
                                 SeedTable(targetConn, tableSchema, sourceConn, scope);
                             }
-                            else if (tableSchema.SourceVersion.Equals(tableSchema.TargetVersion))
+                            else if (tableSchema.SourceVersion == null)
+                            {
+                                LogUnknownSourceVersion(schedule, id, area, tableSchema.Scope);
+                                return;
+                            }
+                            else if (tableSchema.SourceVersion.CurrentVersion.Equals(tableSchema.TargetVersion.CurrentVersion))
                             {
                                 LogAlreadyUpToDate(schedule, id, area);
                             }
@@ -97,7 +102,7 @@ public async Task ProcessSyncJob(SyncJob syncJob, bool globalChangeTracking)
                 }
             );
 
-            if (exceptions.Any())
+            if (exceptions.Count != 0)
             {
                 throw new AggregateException($"{scope} sync failed", exceptions);
             }
@@ -156,6 +161,9 @@ private void SyncTable(SqlConnection targetConn, TableSchema tableSchema, SqlCon
     [LoggerMessage(Level = LogLevel.Information, Message = "{Schedule} {Id} {Area} Already up to date")]
     private partial void LogAlreadyUpToDate(string schedule, string id, string area);
 
+    [LoggerMessage(Level = LogLevel.Warning, Message = "{Schedule} {Id} {Area} Unknown / failed to fetch source version {Scope}.")]
+    private partial void LogUnknownSourceVersion(string schedule, string id, string area, string scope);
+
     [LoggerMessage(Level = LogLevel.Information, Message = "{Schedule} {Id} {Area} End {TableSchemaScope}, duration {Elapsed}")]
     private partial void LogEndTableSchemaScopeDuration(string schedule, string id, string area, string tableSchemaScope, TimeSpan elapsed);