uint32 encoding issue about msgpack HOT 2 CLOSED

Here is the test which you can execute readily:

func TestUint32(t *testing.T) {
	n := uint32(10)
	v := []interface{}{n}

	buf, err := msgpack.Marshal(v)
	if err != nil {
		t.Fatal(err)
	}

	var x interface{}

	err = msgpack.Unmarshal(buf, &x)
	if err != nil {
		t.Fatal(err)
	}

	x2 := x.([]interface{})

	if reflect.TypeOf(v[0]) != reflect.TypeOf(x2[0]) {
		t.Fatalf("Type mismatch, expected %v, got %v", reflect.TypeOf(v[0]), reflect.TypeOf(x2[0]))
	}

}

from msgpack.

There are 2 unrelated issues here:

• you are decoding into interface{} and for simplicity lib returns only int64 and uint64 when decoding numbers. If you need uint32 - replace interface{} with uint32.
• small uint32 numbers are encoded as uint8 (or just small number) to save space. Exact type is loosed, but it does not matter usually because you can decode number into int8/int16/int32/int64 as you need.

I agree that it is a bit confusing, but I think this is the right behavior that does not cause any problems in practise.

from msgpack.