BulkInsert crashes with NotSupportedException whenever I set SetOutputIdentity to true

[goebeler]

I am trying to use BulkInsert to save a set of my DbOjectInstance, but regardless of how I call it, I always receive the following exception.

I am using the EFCore.BulkExtensions NuGet package version 8.1.3., EF Core 8.0.14 and NPSQL 8.0.11

The last EFCore.BulkExtension calls in the callstack are:

• EFCore.BulkExtensions.Core.dll!EFCore.BulkExtensions.TableInfo.LoadOutputEntities<taraxchange.common.sql.Model.DbObjectInstance>(Microsoft.EntityFrameworkCore.DbContext context = {taraxchange.common.sql.ObjectInstancesContext}, System.Type type = {Name = "DbObjectInstance" FullName = "taraxchange.common.sql.Model.DbObjectInstance"}, string sqlSelect = "INSERT INTO "public"."ObjectInstances" ("MetadataId") (SELECT "MetadataId" FROM "public"."ObjectInstancesTemp771d7e8d") ON CONFLICT ("Id") DO UPDATE SET "MetadataId" = EXCLUDED."MetadataId" RETURNING "public"."ObjectInstances"."Id", "public"."ObjectInstances"."MetadataId"") Zeile 1050
• EFCore.BulkExtensions.PostgreSql.dll!EFCore.BulkExtensions.SqlAdapters.PostgreSql.PostgreSqlAdapter.MergeAsync<taraxchange.common.sql.Model.DbObjectInstance>(Microsoft.EntityFrameworkCore.DbContext context = {taraxchange.common.sql.ObjectInstancesContext}, System.Type type = {Name = "DbObjectInstance" FullName = "taraxchange.common.sql.Model.DbObjectInstance"}, System.Collections.Generic.IEnumerable<taraxchange.common.sql.Model.DbObjectInstance> entities = {taraxchange.common.sql.Model.DbObjectInstance[1]}, EFCore.BulkExtensions.TableInfo tableInfo = {EFCore.BulkExtensions.TableInfo}, EFCore.BulkExtensions.OperationType operationType = Insert, System.Action progress = null, bool isAsync = false, System.Threading.CancellationToken cancellationToken = IsCancellationRequested = false) Zeile 311

Can anyone help me find the reason, or even better a solution?

Thanks

[goebeler]

The code causing the issue is:

var testInstance = new DbObjectInstance() { };
ctx.BulkInsert(new[] { testInstance }, new BulkConfig { SetOutputIdentity = true });

[goebeler]

Seems to be the same problem as #1515

[silas-re]

dotnet/runtime#100748
might be related to this, at some point during Expression compilation it seems to try to create a delegate for DbContext.Set, which is a virtual generic method. The top few lines of the Call stack are identical as well

[silas-re]

I was able to trigger the same error with this code, so i think it's caused by using Set<> in a compiled query:

var compiledQuery = EF.CompileQuery<ObjectInstancesContext, DbObjectInstance>(
    c => c.Set<DbObjectInstance>());
var result = compiledQuery(ctx).ToList();

is it possible to simply remove the EF.CompileQuery calls in TableInfo.LoadOutputEntities and use the queries directly? I'm not very familiar with the code of this project, but since the compiled queries aren't reused, I don't think removing the compilation should have a performance impact. Looking at the blame, it seems it was added as a workaround for a memory leak in EF Core 2.x (#73 and #75), which is probably fixed by now.