Pointers to basic types do not deserialize correctly

[losinggeneration]

If you have a basic type that's a pointer, deserialization doesn't happen correctly. For instance:

type Post struct {
    Id      uint64
    Content *string
}

causes a panic during the ValidateStruct step. The validation incorrectly assumes if it's a pointer, it's a pointer to a struct.

A full, stand alone test would be the following

package main

import (
    "log"

    "github.com/go-martini/martini"
    "github.com/martini-contrib/binding"
)

type Post struct {
    Id      uint64
    Content *string
}

func main() {
    c := martini.Classic()
    c.Post("/", binding.Json(Post{}), func(p Post) {
        log.Println(p)
    })
    c.Run()
}

With a curl test of

curl -XPOST --data '{"content": "fubar"}' http://localhost:3000/

$GOROOT/src/pkg/reflect/type.go:654 (0x48a9cd)
        (*rtype).NumField: panic("reflect: NumField of non-struct type")
$GOPATH/src/github.com/martini-contrib/binding/binding.go:191 (0x432512)
        validateStruct: for i := 0; i < typ.NumField(); i++ {
$GOPATH/src/github.com/martini-contrib/binding/binding.go:171 (0x43372a)
        func.005: errors = validateStruct(errors, obj)

I've also done a quick JSON test case with the following commit: https://github.com/losinggeneration/binding/commit/58a8515eb2be7b5226273e09fbd660b9f8a17457

[mholt]

Good find, thanks for the reproducible case.

Can you confirm that changing line 200 of binding.go to this fixes the problem:

            (field.Type.Kind() == reflect.Ptr && !reflect.DeepEqual(zero, fieldValue) &&
                field.Type.Elem().Kind() == reflect.Struct) {

Notice the extra condition that the field's type's Elem() must be a Struct kind before going into validate it.

[losinggeneration]

That does indeed look like it fixes the problem. The test case doesn't work here because it's comparing the pointer locations and not the underlying data.

[mholt]

Awesome, thank you! I'll get the fix rolled out shortly.