Rethink deep templates

[pauxus]

given the following template:

def template = Outer.Create.Template {
  inner {
    innerValue "1"
  }
}

And applied to the following config:

TemplateManager.withTemplate(template) {
  Outer.Create.With {
    inner {
      anotherValue "1"
    }
  }
}

would result in the creation of a completely new inner object, so the "innerValue" would be dropped, which is counterintuitive.

I see a couple of possibilities to implement this:

1) A complex template could be split into multiple templates which are all applied at once. With layer3 code, this is easy to implement, however, this has two issues:

• It would not work with "copyFrom"
• When an inner object is used at different places in the model, all those places under the template would be affected 2) Copy strategies could be used not only for copyFrom, but for all operations (i.e. multiple dsl calls of the same field would result in a merging of the dsl objects according to the given merge strategy.

Both approaches are breaking changes. (2) seems better, but depends on more work on copyStrategies and is more complex in implementation but probably the way to got.