[Internal] Add StructToSchema for Plugin Framework

[edwardfeng-db]

Changes

• Addressed comments in [Feature] Introduced Terraform Plugin Framework #3893
• Adding StructToSchema and corresponding unit tests, as well as tests for CustomizableSchema

Tests

• make test run locally
• relevant change in docs/ folder
• covered with integration tests in internal/acceptance
• relevant acceptance tests are passing
• using Go SDK

[mgyucht]

Few comments on this one, but mostly looking great!

[mgyucht]

Suggested change

	if kind == reflect.Ptr {
	elem := typeField.Type.Elem()
	sv := reflect.New(elem).Elem()
	nestedScm := typeToSchema(sv)
	scm[fieldName] = SingleNestedAttributeBuilder{Attributes: nestedScm, Optional: isOptional, Required: !isOptional}
	} else if kind == reflect.Slice {
	value := field.Value
	if kind == reflect.Ptr {
	kind = typeField.Type.Elem().Kind()
	value := field.Elem()
	}
	if kind == reflect.Slice {

Then on line 83 we use this value instead of field.Value. This means that pointers always receive consistent treatment as if they were not pointers from the perspective of schema calculation. It's basically the equivalent to lines 17-20.

[edwardfeng-db]

Updated, I think for the value field, it actually is a bit more complex than that. I tried field.Value.Elem() but that gave me an error for "zero value" when I do value.Interface(), so I ended up using reflect.New to create a new instance

[mgyucht]

For these default cases, these are always types defined in the Go SDK right?

[edwardfeng-db]

Yes kind of, these will the nested structs and they will be in the same form as in the gosdk but they'll still live in the tf_sdk package.

The primitive fields nested inside of these structs will still use the tf types