Problem with validating slice struct fields

[noonien]

The following test:

func TestInStruct(t *testing.T) {
    var v struct {
        Field []string
    }
    v.Field = []string{"v1"}

    err := ValidateStruct(&v,
        Field(&v.Field, In("v1", "v2")),
    )
    if err != nil {
        t.Fatal(err)
    }
}

Fails with: Field: must be a valid value.

[qiangxue]

This is expected. The In rule checks if a value can be found in the list of prespecified values. See the code doc below: // Note that the value being checked and the possible range of values must be of the same type.

[noonien]

I see, how does one validate such a case though? Should In() not work with slice types?

[qiangxue]

You are trying to determine if a string slice is "in" another string slice. This is not well defined - should the former be fully included in the latter, or should it allow partial intersection?

You will need to have a custom rule to support this check. You may refer to the in.go file for details. It's not very complicated.

[noonien]

Well, such a field would be valid if all elements in it are valid.

But I understand why creating a new rule makes more sense.