deepcopy: val.DeepCopyinterface undefined

[antoineco]

The following types:

type Foo struct {
	metav1.TypeMeta
	metav1.ObjectMeta
	Spec FooSpec
}

type FooSpec struct {
	Parameters map[string]interface{}
}

yield the following code:

// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
func (in *FooSpec) DeepCopyInto(out *FooSpec) {
	*out = *in
	if in.Parameters != nil {
		in, out := &in.Parameters, &out.Parameters
		*out = make(map[string]interface{}, len(*in))
		for key, val := range *in {
			if val == nil {
				(*out)[key] = nil
			} else {
				(*out)[key] = val.DeepCopyinterface{}()
			}
		}
	}
	return
}

which yields the following compiler error:

val.DeepCopyinterface undefined (type interface {} is interface with no methods

[antoineco]

I understand why now. Interfaces must implement DeepCopy<Type-Name>(), so one must rewrite the above FooSpec type like:

type FooSpec struct {
	Parameters map[string]P
}

type P interface {
	DeepCopyP() P
}

[yuchengwu]

But interface{} and P are different things. interface{} is an empty interface may hold values of any type, P holds values of any type that must implement DeepCopyP() method.

[antoineco]

Yes, I created a dummy type because I couldn't think of a better way.

[yuchengwu]

Me too, currently I manually replace val.DeepCopyinterface{}() with Copy(val), not a solution but it works

[lzcmoody]

Hi, I found a workaround to solve this issue, anyway it's works.

type FooSpec struct { Parameters Values json:"parameters,omitempty" }
type Values struct { Objects map[string]interface{} json:"Objects,omitempty" }
func (in *Values) DeepCopyInto(out *Values) { // here's you deepcopy implementation }

If you define your own DeepCopyInfo in types.go, zz_generated.deepcopy.go will not auto-generate this function.