source with nil pointer replacing existing pointer in destination

[iDevoid]

Reproducible Example

go playground

Description

expectation

Should not replace non-nil pointer with nil or non existing data

[kcchu]

This is the line of code that lead to this behavior:

copier/copier.go

Lines 462 to 467 in 0e264e9

	if to.Kind() == reflect.Ptr {
	// set `to` to nil if from is nil
	if from.Kind() == reflect.Ptr && from.IsNil() {
	to.Set(reflect.Zero(to.Type()))
	return true
	} else if to.IsNil() {

But it seems to me that it is that intended behavior because a nil is also a value that should be copied as if other values. Setting IgnoreEmpty in copier.Option could achieve what you want. However, not only it would ignore nil pointers in source, but also ignore zero values such as empty strings.