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pointer bug #11
Description
type A struct {
BS []B
}
type B struct {
C
}
type C struct {
Index int
}
func (c C) String() string {
return fmt.Sprint("index", c.Index)
}
func main() {
mapper := mapify.Mapper{}
mapper.MapValue = func(path string, e mapify.Element) (any, error) {
fmt.Println("path:", path)
return e.Value.Interface(), nil
}
a := A{}
a.BS = []B{B{C{Index:1}},B{C{Index:2}}}
fmt.Println(mapper.MapAny(a))
}
path: .BS
path: .BS[0].C
path: .BS[0].C.Index
path: .BS[1].C
path: .BS[1].C.Index
map[BS:[map[C:map[Index:1]] map[C:map[Index:2]]]] <nil>
but
type A struct {
BS []*B
}
type B struct {
C
}
type C struct {
Index int
}
func (c C) String() string {
return fmt.Sprint("index", c.Index)
}
func main() {
mapper := mapify.Mapper{}
mapper.MapValue = func(path string, e mapify.Element) (any, error) {
fmt.Println("path:", path)
return e.Value.Interface(), nil
}
a := A{}
a.BS = []*B{&B{C{Index:1}},&B{C{Index:2}}}
fmt.Println(mapper.MapAny(a))
}
path: .BS
map[BS:[index1 index2]] <nil>
Activity
elgopher commentedon Jan 15, 2026
thank you @anpic for reporting a bug! Somehow I missed the notification about it. I will look at the issue in the evening.
elgopher commentedon Jan 15, 2026
@anpic I confirm, that mapping of slices of pointers is not implemented at all. Thank you for finding this out! The reason why this is not implemented is pretty simple - I don't use such slices, so I never wanted such feature :) But I admit, that some people may want to use them and that this feature should be implemented.
I've created a PR with the fix: #12
So far, in the PR, I have added support for slices of pointers to structs. But there are other types of pointers like
[]*mapor[]*[]string, which should be supported as well, I guess. It will take some time to finish the implementation, so I marked the PR as a draft (work in progress). I will let you know when it is finished.