NullReferenceException in NpgsqlCompositeMethodCallTranslator.cs @ line 66

[CodingGorilla]

After upgrading my project to .NET Core 2.1 and Npgsql.EntityFrameworkCore.PostgreSQL 2.1.0 I'm getting an NRE at startup in the NpgsqlCompositeMethodCallTranslator.cs at line 66. This appears to be because the INpgsqlOptions passed into the constructor has a null Plugins member, and the constructor is attempting to iterate the plugins.

Did something change in the set up of the context, because this works fine when I switch back to 2.0.

[austindrenski]

It shouldn't be possible to initialize INpgsqlOptions with a null Plugins member.

The current version will allow you to pass in null NpgsqlEntityFrameworkPlugin instances. (This should change with #483 for version 2.2.)

Do you add any plugins during startup? Could you post a snippet showing your configuration for Npgsql?

[CodingGorilla]

My configuration is pretty simple:

            services
                .AddEntityFrameworkNpgsql()
                .AddDbContext<WaterVaporContext>(opts => opts.UseNpgsql(Configuration.GetConnectionString("WaterVapor")));

So in this case, is the INpgsqlOptions the opts lambda here?

[austindrenski]

Could you post the stack trace?

[CodingGorilla]

This happens immediately at start up:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Npgsql.EntityFrameworkCore.PostgreSQL.Query.ExpressionTranslators.Internal.NpgsqlCompositeMethodCallTranslator..ctor(RelationalCompositeMethodCallTranslatorDependencies dependencies, INpgsqlOptions npgsqlOptions) in C:\projects\EFCore.PG\src\EFCore.PG\Query\ExpressionTranslators\Internal\NpgsqlCompositeMethodCallTranslator.cs:line 66
   at Jasper.Generated.Microsoft_EntityFrameworkCore_Query_ExpressionTranslators_ICompositeMethodCallTranslator_npgsqlCompositeMethodCallTranslator.Build(Scope scope)
   at Lamar.IoC.Resolvers.SingletonResolver`1.Resolve(Scope scope)
   at Lamar.IoC.Instances.GeneratedInstance.Resolve(Scope scope)
   at Lamar.IoC.Scope.<>c__DisplayClass41_0.<QuickBuild>b__0(ParameterInfo x)
   at System.Linq.Enumerable.SelectArrayIterator`2.ToArray()
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at Lamar.IoC.Scope.QuickBuild(Type objectType)
   at Lamar.IoC.Instances.GeneratedInstance.AttachResolver(Scope root)
   at Lamar.ServiceGraph.Initialize(PerfTimer timer)
   at Lamar.IoC.Scope..ctor(IServiceCollection services, PerfTimer timer)
   at Lamar.LamarServiceProviderFactory.CreateServiceProvider(ServiceRegistry containerBuilder)
   at Microsoft.AspNetCore.Hosting.Internal.StartupLoader.ConfigureServicesDelegateBuilder`1.<>c__DisplayClass14_0.<ConfigureServices>g__ConfigureServicesWithContainerConfiguration|0(IServiceCollection services)
   at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.ConfigureServices(IServiceCollection services)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices()
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.Initialize()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

In this case, Lamar is the IoC container.

[austindrenski]

I'm not familiar with Lamar or Jasper, but I do work with the common ASP.NET Core stack.

Can you provide a minimal reproduction repo? Ideally, without Lamar and Jasper, but if that's too much work, that's okay too.

[CodingGorilla]

I will see if I can reproduce it without Lamar (I'm not using Jasper in this particular project). But I would also point out that this code does work with Lamar and ASP/EF Core 2.0 and Npgsql.EntityFrameworkCore.PostgreSQL 2.02. It only breaks when upgrading to 2.1 of the aforementioned packages.

[austindrenski]

(I'm not using Jasper in this particular project)

Hmm... okay. This is in the stack trace, but not necessarily important.

at Jasper.Generated.Microsoft_EntityFrameworkCore_Query_ExpressionTranslators_ICompositeMethodCallTranslator_npgsqlCompositeMethodCallTranslator.Build(Scope scope)

But I would also point out that this code does work with Lamar and ASP/EF Core 2.0 and Npgsql.EntityFrameworkCore.PostgreSQL 2.02. It only breaks when upgrading to 2.1 of the aforementioned packages.

Well-noted—the goal is just to triage the source, and its easier to help triage if I'm familiar with the stack.

[CodingGorilla]

Understood, can you point me at where and how the IoC registration for the INpgsqlOptions should be generated?

[austindrenski]

@CodingGorilla The relevant files are located here and here. I'm going to close this issue for now since it looks like this is IoC related. But please post back here if JasperFx/lamar#62 finds this to be an issue on our end.

[CodingGorilla]

This was indeed an issue with the IoC container, I can't really explain what it was other than it appeared to be an order of construction issue, but the latest version of the package resolved the problem.

[austindrenski]

Thanks for letting us know, glad to hear it's working!

[roji]

Great, thanks to everyone for investigating...