Upgrading from Autofac 7.x to 8.x

Very little changed for most people in the 8.x line. Beyond the target framework updates, there are two breaking changes, both narrow enough that you will probably only meet them if you write code against Autofac’s internals.

• ResolveRequest became a readonly struct, where it had been a class. Code that treats it as a reference type no longer compiles - comparing one to null is the usual way this shows up. It is also copied by value now, so a method taking one cannot mutate the caller’s copy. This only affects code that handles ResolveRequest directly, which in practice means custom resolve middleware or a custom IInstanceActivator.

• The shim RequiresUnreferencedCodeAttribute that Autofac declares for older target frameworks changed from public to internal in 8.4.0. If you were applying that attribute in your own code and picking up Autofac’s declaration of it, declare your own or reference the framework one instead.