Fix GenericMap.DeepCopyInto (#1844)

[njhale]

Convert GenericMap to and from JSON on DeepCopyInto. This circumvents
the use of runtime.DeepCopyJSON, which panics when int values
exist in the map.

Addresses #1844

[thedadams]

As I understand, DeepCopyJSON doesn't support int because that type differs based on the platform, but it does support int64.

I understand that changing our use of int to int64 would be a much bigger change, but would that give us an advantage here? Should our ObjectMeta types just always use int64?

Just want to get your thoughts on this.

[njhale]

@thedadams thanks for taking a look at this!

As I understand, DeepCopyJSON doesn't support int because that type differs based on the platform, but it does support int64.

yup, that's my read too

I understand that changing our use of int to int64 would be a much bigger change, but would that give us an advantage here? Should our ObjectMeta types just always use int64?

I think that's reasonable. After all, there are quite a few places where we're already forced into explicitly using int64; for example, the limit field of ListOptions is int64.

but for this particular situation -- run args in a GenericMap -- I'm not sure at the moment how we could apply that constraint globally.

[ibuildthecloud]

The GenericMap has also assumed that the data is only native json types. So for example you can put a struct in there. I'm fine with not allowing int. If we really really want it, we can just copy the deepcopy function and add int. That exact logic I've written tons of time and you will probably find it at least twice somewhere in acorn/baaah already.

I believe the reason int isn't supported is because json.Unmarshal will never produce an int. It only creates int64, float64, json.Number.