Sanitising multiple inputs in one field. (multidimensional array)

Can you pastebin the complete block you’re using for this? I want to tinker around and see what’s going on here.

From the looks of the error you pasted above, it’s a case of passing in an array to the wp_check_invalid_utf8() function, whether directly or through a chain of function calls.

Can you also pastebin the metabox setup? This looks like half of what would be needed to recreate.

Not sure about any donation links for CMB2, and I won’t take direct donations. Especially since it’s not me doing most of the work on CMB2

After about an hour of tinkering, I think this will get you back on a good foot forward, and you can work on your render callback more with preserved values.

I found that I was able to get the preserved values into the render callback by setting the escape_cb to false if you want to bypass completely, though you probably should escape as attributes, using esc_attr(). The other part is the sanitization_cb parameter. If none are provided for either one, then my digging through the CMB2 source code showed that it always fell back to sanitize_text_field() for the security, and that caused the arrays to be cast as string and just stored “Array” as the value.

I’d personally recommend using both ‘escape_cb’ and ‘sanitization_cb’ and just provide a function name for the callbacks. In the callbacks, loop over passed in values and sanitize each index, before reconstructing the same array structure and returning.

Examples:

$test_metabox->add_field( array(
	'name' => __( 'Allergier', 'textdomain' ),
	'desc' => __( '', 'textdomain' ),
	'id'   => $prefix . 'allergies_test',
	'type' => 'dish_allergies',
	'escape_cb' => 'barfoo',
	'sanitization_cb' => 'foobar',
) );

function foobar( $a, $b, $c ) {
	// Sanitize here.
	return $a;
}
function barfoo( $a, $b, $c, ) {
	// Escape here.
	return $a;
}

The first parameter in both are going to be the values submitted. In your example, an array of arrays, the first being ‘gluten’ storing it’s own array of the bool checkbox and the type, and repeated for the ‘nuts’ index.

The second parameter looks like an object holding the field type info, the third parameter would be the CMB2_Field instance with a bit more info available to you. Likely only really need the first parameter unless you need to conditionally apply things. You would also be able to get rid of the cmb2_sanitize_dish_allergies add_filter line, as all my testing never ended up reaching that once I provided the sanitization_cb parameter. Just provide the same callback function name in that spot in the add_field().