Make `SwaggerGenerator`'s private methods `protected virtual`

I've come across this usecase where I wanted to serve the same OpenAPI document twice with two different sets of operation IDs.

It would have been easier if I could inject ISwaggerGenerator inside an IDocumentFilter implementation,

private class CloneDocumentFilter: IDocumentFilter
{
    private ISwaggerProvider _provider;

    public CloneDocumentFilter(ISwaggerProvider provider)
    {
        _provider = provider;
    }

    public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
    {
        var doc = _provider.GetSwagger("v1");
        var paths = doc.Paths;
        // ...modify operations
        swaggerDoc.Paths = paths;
    }
}

but I hit this wall:

exception I get

System.InvalidOperationException: ValueFactory attempted to access the Value property of this instance.
    at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
    at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
    at System.Lazy`1.CreateValue()
    at System.Lazy`1.get_Value()
    at Microsoft.Extensions.Options.OptionsCache`1.GetOrAdd(String name, Func`1 createOptions)
    at Microsoft.Extensions.Options.OptionsManager`1.Get(String name)
    at Microsoft.Extensions.Options.OptionsManager`1.get_Value()
    at Microsoft.Extensions.DependencyInjection.SwaggerGenServiceCollectionExtensions.<>c.b__0_1(IServiceProvider s)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.b__0(ServiceProviderEngineScope scope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
    at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
    at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, Object[] parameters)
    at Swashbuckle.AspNetCore.SwaggerGen.ConfigureSwaggerGeneratorOptions.CreateFilter[TFilter](FilterDescriptor filterDescriptor)
    at Swashbuckle.AspNetCore.SwaggerGen.ConfigureSwaggerGeneratorOptions.<>c__DisplayClass4_0.b__3(FilterDescriptor filterDescriptor)
    at System.Collections.Generic.List`1.ForEach(Action`1 action)
    at Swashbuckle.AspNetCore.SwaggerGen.ConfigureSwaggerGeneratorOptions.Configure(SwaggerGeneratorOptions options)
    at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
    at Microsoft.Extensions.Options.OptionsManager`1.<>c__DisplayClass5_0.b__0()
    at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
    at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
    at System.Lazy`1.CreateValue()
    at System.Lazy`1.get_Value()
    at Microsoft.Extensions.Options.OptionsCache`1.GetOrAdd(String name, Func`1 createOptions)
    at Microsoft.Extensions.Options.OptionsManager`1.Get(String name)
    at Microsoft.Extensions.Options.OptionsManager`1.get_Value()
    at Microsoft.Extensions.DependencyInjection.SwaggerGenServiceCollectionExtensions.<>c.b__0_1(IServiceProvider s)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.b__0(ServiceProviderEngineScope scope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
    at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
    at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.GetService(IServiceProvider sp, Type type, Type middleware)
    at lambda_method1(Closure , Object , HttpContext , IServiceProvider )
    at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass5_1.b__2(HttpContext context)
    at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

So I decided to go with a custom ISwaggerProvider, but it has no virtual methods. This means I can't access to runtime information to enhance operation ids inside a subclass without reimplementing the whole logic. All I have is the what's left after Swashbuckle does its thing.

class SwaggerDocCustomOperationIdProvider : SwaggerGenerator, ISwaggerProvider
{
    public SwaggerDocCustomOperationIdProvider(SwaggerGeneratorOptions options,
                                               IApiDescriptionGroupCollectionProvider apiDescriptionsProvider,
                                               ISchemaGenerator schemaGenerator) : base(options,
        apiDescriptionsProvider, schemaGenerator)
    {
    }

    public new OpenApiDocument GetSwagger(string documentName, string host = null, string basePath = null)
    {
        // ...
        var doc = base.GetSwagger(documentName, host, basePath);
        var operations = doc.Paths
            .SelectMany(p => p.Value.Operations.Values)
            .ToList();

        foreach (var op in operations)
        {
            // modify the operation info
        }

        return doc;
    }
}

If would be nice if methods of the SwaggerGenerator were protected virtual so I could override & modify their output and still have access to ApiDescription info ASP.NET Core provides.

https://github.com/domaindrivendev/Swashbuckle.AspNetCore/blob/21391c2ea7dcb407784689ad861560623169673f/src/Swashbuckle.AspNetCore.SwaggerGen/SwaggerGenerator/SwaggerGenerator.cs#L134

domaindrivendev / Swashbuckle.AspNetCore

Make `SwaggerGenerator`'s private methods `protected virtual` #2152