panic on null in texture UV indices of a CompositeSurface

[balazsdukai]

If one of the UV indices in a ring of a CompositeSurface texture is null, cjval panics. This only happens if the other UV indices in the same ring are not null.

This file panics:
cjfake_invalid_0_copy.json
But if you change the null in L31 to 1, the file is valid. Note that having a null for the whole ring is fine, like in case of the first surface.

"values": [
    [[null]],
    [[0, null, 0, 0, 0, 1], [0, 0, 0, 2, 1, 0, 1], [2, 2, 2, 0, 0, 0, 2, 2, 1]]
]

The cause of the panic is the unwrap in

cjval/src/lib.rs

Line 1491 in afeb6e3

if each.unwrap() > (max_i_v - 1) {

. The problem in case of this file is that only the first item in the array is checked for having a value in

cjval/src/lib.rs

Line 1482 in afeb6e3

if y.len() > 1 && y[0].is_some() {

, hence the first surface is handled correctly, but if the null is hidden in the ring, cjval tries to unwrap a None.