Can you give an example? I'm not sure what you mean by "generic framework code can inject".

@cgruber some of our tests have a test runner that injects the test case:

@Override public void beforeTest(Method method) {
  makeObjectGraph().inject(this);
}

This is especially useful for integration testing.

Unfortunately we use the same test runner for several tests, and sometimes the injected test doesn't have any @Inject annotated fields. We need to avoid crashing in that case.

So inject() in this case is basically doing a no-op? I can see the utility, but it feels unsafe - like someone will pass in something with no @Inject and end up not realizing until run-time that nothing happened.

This feels like an alternate graph implementation with different behaviour suitable for testing, to be honest. I'm not sure this behaviour is the right one in all cases.

Or an injector with some configuration points with strict defaults.

Yeah, the inject() call is a no-op. For us it's come up in several places, mostly in framework code that blindly injects an instance of an abstract type like TestCase or Activity.

Since the offending type still needs to be explicitly registered as an injection point, it's hard to be surprised by this.

Ah - fair point. Ok... as long as we keep some explicit signal there and don't end up with some situation where someone can trip over it. Still less strict than I'd like, but you're right - the class is at least deliberately added.