[SQL-Migration] Port changes to new migration service (#1835)

This PR ports some changes that were missed to the new, separated Migration Service project.

Here is the PR to separate Migration Service into project: #1828

Changes from the following PRs were not ported over:
[SQL Migration] Mark SQL MI premium-series memory optimized SKUs as GA #1811
Update login migrations nuget with perf improvements #1789

src/Microsoft.SqlTools.Migration/MigrationService.cs

@@ -546,21 +546,6 @@ namespace Microsoft.SqlTools.Migration
                 prefs.EligibleSkuCategories = GetEligibleSkuCategories("AzureSqlManagedInstance", parameters.IncludePreviewSkus);
                 resultSet.sqlMiResults = provider.GetSkuRecommendation(prefs, req);
 
-                // if no result was generated, create a result with a null SKU
-                if (!resultSet.sqlMiResults.Any())
-                {
-                    resultSet.sqlMiResults.Add(new SkuRecommendationResult()
-                    {
-                        SqlInstanceName = parameters.TargetSqlInstance,
-                        DatabaseName = null,
-                        TargetSku = null,
-                        MonthlyCost = null,
-                        Ranking = -1,
-                        PositiveJustifications = null,
-                        NegativeJustifications = null,
-                    });
-                }
-
                 sqlMiStopwatch.Stop();
                 resultSet.sqlMiDurationInMs = sqlMiStopwatch.ElapsedMilliseconds;
 
@@ -582,21 +567,6 @@ namespace Microsoft.SqlTools.Migration
                 prefs.EligibleSkuCategories = GetEligibleSkuCategories("AzureSqlVirtualMachine", parameters.IncludePreviewSkus);
                 resultSet.sqlVmResults = provider.GetSkuRecommendation(prefs, req);
 
-                // if no result was generated, create a result with a null SKU
-                if (!resultSet.sqlVmResults.Any())
-                {
-                    resultSet.sqlVmResults.Add(new SkuRecommendationResult()
-                    {
-                        SqlInstanceName = parameters.TargetSqlInstance,
-                        DatabaseName = null,
-                        TargetSku = null,
-                        MonthlyCost = null,
-                        Ranking = -1,
-                        PositiveJustifications = null,
-                        NegativeJustifications = null,
-                    });
-                }
-
                 sqlVmStopwatch.Stop();
                 resultSet.sqlVmDurationInMs = sqlVmStopwatch.ElapsedMilliseconds;
 
@@ -632,11 +602,6 @@ namespace Microsoft.SqlTools.Migration
                 List<AzureSqlSkuCategory> eligibleSkuCategories = GetEligibleSkuCategories("AzureSqlDatabase", parameters.IncludePreviewSkus);
                 ElasticStrategySKURecommendationPipeline pi = new ElasticStrategySKURecommendationPipeline(eligibleSkuCategories);
                 DataTable SqlMISpec = pi.SqlMISpec.Copy();
-                if (!parameters.IncludePreviewSkus)
-                {
-                    SqlMISpec = pi.SqlMISpec.AsEnumerable().Where(
-                    p => !p.Field<string>("SLO").Contains("Premium")).CopyToDataTable();
-                }
                 MISkuRecParams MiSkuRecParams = new MISkuRecParams(pi.SqlGPMIFileSpec, SqlMISpec, elasticaggregator.FileLevelTs, elasticaggregator.InstanceTs, pi.MILookupTable, Convert.ToDouble(parameters.ScalingFactor) / 100.0, parameters.TargetSqlInstance);
                 DbSkuRecParams DbSkuRecParams = new DbSkuRecParams(pi.SqlDbSpec, elasticaggregator.DatabaseTs, pi.DbLookupTable, Convert.ToDouble(parameters.ScalingFactor) / 100.0, parameters.TargetSqlInstance);
                 resultSet.sqlDbResults = pi.ElasticStrategyGetSkuRecommendation(MiSkuRecParams, DbSkuRecParams, req);
@@ -662,30 +627,10 @@ namespace Microsoft.SqlTools.Migration
                 List<AzureSqlSkuCategory> eligibleSkuCategories = GetEligibleSkuCategories("AzureSqlManagedInstance", parameters.IncludePreviewSkus);
                 ElasticStrategySKURecommendationPipeline pi = new ElasticStrategySKURecommendationPipeline(eligibleSkuCategories);
                 DataTable SqlMISpec = pi.SqlMISpec.Copy();
-                if (!parameters.IncludePreviewSkus)
-                {
-                    SqlMISpec = pi.SqlMISpec.AsEnumerable().Where(
-                    p => !p.Field<string>("SLO").Contains("Premium")).CopyToDataTable();
-                }
                 MISkuRecParams MiSkuRecParams = new MISkuRecParams(pi.SqlGPMIFileSpec, SqlMISpec, elasticaggregator.FileLevelTs, elasticaggregator.InstanceTs, pi.MILookupTable, Convert.ToDouble(parameters.ScalingFactor) / 100.0, parameters.TargetSqlInstance);
                 DbSkuRecParams DbSkuRecParams = new DbSkuRecParams(pi.SqlDbSpec, elasticaggregator.DatabaseTs, pi.DbLookupTable, Convert.ToDouble(parameters.ScalingFactor) / 100.0, parameters.TargetSqlInstance);
                 resultSet.sqlMiResults = pi.ElasticStrategyGetSkuRecommendation(MiSkuRecParams, DbSkuRecParams, req);
 
-                // if no result was generated, create a result with a null SKU
-                if (!resultSet.sqlMiResults.Any())
-                {
-                    resultSet.sqlMiResults.Add(new SkuRecommendationResult()
-                    {
-                        SqlInstanceName = parameters.TargetSqlInstance,
-                        DatabaseName = null,
-                        TargetSku = null,
-                        MonthlyCost = null,
-                        Ranking = -1,
-                        PositiveJustifications = null,
-                        NegativeJustifications = null,
-                    });
-                }
-
                 sqlMiStopwatch.Stop();
                 resultSet.sqlMiDurationInMs = sqlMiStopwatch.ElapsedMilliseconds;
 
@@ -701,19 +646,8 @@ namespace Microsoft.SqlTools.Migration
             // generate SQL VM recommendations, if applicable
             if (parameters.TargetPlatforms.Contains("AzureSqlVirtualMachine"))
             {
-                // elastic model currently doesn't support VM recommendation, return null SKU for now                
+                // elastic model currently doesn't support VM recommendation, return empty list                
-                resultSet.sqlVmResults = new List<SkuRecommendationResult> {
+                resultSet.sqlVmResults = new List<SkuRecommendationResult> { };
-                    new SkuRecommendationResult()
-                    {
-                        SqlInstanceName = parameters.TargetSqlInstance,
-                        DatabaseName = null,
-                        TargetSku = null,
-                        MonthlyCost = null,
-                        Ranking = -1,
-                        PositiveJustifications = null,
-                        NegativeJustifications = null,
-                    }
-                };
                 resultSet.sqlVmDurationInMs = -1;
                 resultSet.sqlVmReportPath = String.Empty;
             }
@@ -935,8 +869,6 @@ namespace Microsoft.SqlTools.Migration
                                                     ComputeTier.Provisioned,
                                                     AzureSqlPaaSHardwareType.PremiumSeries));
 
-                    if (includePreviewSkus)
-                    {
                         // Premium Memory Optimized BC/GP
                         eligibleSkuCategories.Add(new AzureSqlSkuPaaSCategory(
                                                         AzureSqlTargetPlatform.AzureSqlManagedInstance,
@@ -951,7 +883,6 @@ namespace Microsoft.SqlTools.Migration
                                                         AzureSqlPaaSServiceTier.GeneralPurpose,
                                                         ComputeTier.Provisioned,
                                                         AzureSqlPaaSHardwareType.PremiumSeriesMemoryOptimized));
-                    }
                     break;
 
                 case "AzureSqlVirtualMachine":
@@ -971,7 +902,6 @@ namespace Microsoft.SqlTools.Migration
                         vmCapabilities.AddRange(vmPreviewCapabilities);
                     }
 
-
                     foreach (VirtualMachineFamily family in AzureVirtualMachineFamilyGroup.FamilyGroups[VirtualMachineFamilyType.GeneralPurpose]
                         .Concat(AzureVirtualMachineFamilyGroup.FamilyGroups[VirtualMachineFamilyType.MemoryOptimized]))
                     {

src/Microsoft.SqlTools.Migration/Utils/ExtensionMethods.cs

@@ -13,6 +13,11 @@ namespace Microsoft.SqlTools.Migration.Utils
     {
         public static void AddExceptions(this IDictionary<string, IEnumerable<ReportableException>> exceptionMap1, IDictionary<string, IEnumerable<ReportableException>> exceptionMap2)
         {
+            if (exceptionMap1 is null || exceptionMap2 is null)
+            {
+                return;
+            }
+
             foreach (var keyValuePair2 in exceptionMap2)
             {
                 // If the dictionary already contains the key then merge them