System.NullReferenceException for invalid appsettings.json

[meikeric]

This took me a while to track down...
As I was porting a project from dnx to dotnet I came across this issue.

I missed a closing curly brace "}" in the appsettings.json file. VS does warn if I had the file opening, however, I didn't think to look there until after walking the code.

The invalid json throws a Null Reference exception. I feel that there should be some json validation further upstream, maybe JsonConfigurationProvider.Load and throw an appropriate invalid Json exception there.

System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.Extensions.Configuration.Json.JsonConfigurationProvider.RetrieveErrorContext(JsonReaderException e, IEnumerable1 fileContent) at Microsoft.Extensions.Configuration.Json.JsonConfigurationProvider.Load(Stream stream) at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load(Boolean reload) at Microsoft.Extensions.Configuration.ConfigurationRoot..ctor(IList1 providers)
at Microsoft.Extensions.Configuration.ConfigurationBuilder.Build()
at XXXX.Startup..ctor(IHostingEnvironment env) in XXXX\Startup.cs:line 45
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.Extensions.Internal.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
at Microsoft.AspNetCore.Hosting.Internal.StartupLoader.LoadMethods(IServiceProvider services, Type startupType, String environmentName)
at Microsoft.AspNetCore.Hosting.WebHostBuilderExtensions.<>c__DisplayClass1_0.b__1(IServiceProvider sp)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureStartup()
at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices()
at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

[vsg24]

Agreed 1000000%. The current exception doesn't give any useful info, it should be replaced with a more meaningful one.

[giggio]

Just had this problem now. Really cryptic. This should be handled better, definitely.

[HaoK]

74c68cd

[giggio]

Looks much better now. Thanks @HaoK .