7 invalid inject

[tristanexsquare]

Added a test case for the issue and started with first approach to detect struct receivers by comparing the instance with an empty instance. It seems not to be possible to find out struct receivers using reflection.

Current solution is not working for cases with struts that have no fields. See failing test cases...

[bastianccm]

Hi @tristanessquare,

thank you for looking into this issue!
The current approach of comparing the result will probably fail if an empty struct is used in a binding (which is a valid case), so after requestInjection the resulting struct is still empty.

Currently, the logic checks for a Inject method on the pointer type, then calls that and dereferences the element:

dingo/dingo.go

Lines 698 to 708 in 72b6052

	case reflect.Ptr:
	if setup := current.MethodByName("Inject"); setup.IsValid() {
	args := make([]reflect.Value, setup.Type().NumIn())
	for i := range args {
	if args[i], err = injector.getInstance(setup.Type().In(i), "", circularTrace); err != nil {
	return wrapErr(err)
	}
	}
	setup.Call(args)
	}
	injectlist = append(injectlist, current.Elem())

After dereferencing, it goes through all fields if it's a struct type.
I think we should check if it's not a pointer but still has an Inject method present, and if so, we should fail there.

Something along the lines of

if ctype.Kind() != reflect.Ptr && current.MethodByName("Inject").IsValid() {
    return errInvalidInject
}

prior to the switch

dingo/dingo.go

Line 696 in 72b6052

switch ctype.Kind() {

What do you think?

[tristanexsquare]

Hi @bastianccm ,

thank you for the great idea. This seems to solve the problem. Now my new test and the existing ones are green.

[bastianccm]

Hi @tristanessquare,

thank you for fixing it! Just mark this ready when you are, and I'm happy to merge it!