Hi John,
I’ve tested again with a clean install to make sure it’s not in my codebase.
I took the latest WP 5.9 + latest ACF 5.11.4 and added the following to the function.php to trigger the error:
acf_add_local_field_group([
"key" => "group_Feature toggles",
"title" => "Feature Toggles",
"fields" => [
[
"type" => "true_false",
"name" => "anchor_tags",
"label" => "Anchor Tags",
"key" => "field_feature_toggles_anchor_tags",
],
]
]);
get_field('anchor_tags', 'option');
Yes wrapping it in acf/init suppresses the notice but as the documentation states it should not be required. acf_maybe_get_field triggers init before it gets the value. So even without wrapping it will always be initialized looking at the code.
I’ve been digging in the ACF codebase and I think the root cause lies within the acf_maybe_get_field code:
/*
* acf_get_object_field
*
* This function will return a field for the given selector.
* It will also review the field_reference to ensure the correct field is returned which makes it useful for the template API
*
* @type function
* @date 4/08/2015
* @since 5.2.3
*
* @param $selector (mixed) identifyer of field. Can be an ID, key, name or post object
* @param $post_id (mixed) the post_id of which the value is saved against
* @param $strict (boolean) if true, return a field only when a field key is found.
* @return $field (array)
*/
function acf_maybe_get_field( $selector, $post_id = false, $strict = true ) {
// init
acf_init();
// Check if field key was given.
if ( acf_is_field_key( $selector ) ) {
return acf_get_field( $selector );
}
// Lookup field via reference.
$post_id = acf_get_valid_post_id( $post_id );
$field = acf_get_meta_field( $selector, $post_id );
if ( $field ) {
return $field;
}
// Lookup field loosely via name.
if ( ! $strict ) {
return acf_get_field( $selector );
}
// Return no result.
return false;
}
When get_field is called the second thing it does is call acf_maybe_get_field.
So what happens:
1) init
2) check if key (it’s not)
3) try to get the field using the hidden metadata using acf_get_meta_field which will fail because it has not yet been saved to the database.
4) $strict is true so it will not trigger acf_get_field
5) now we return false.
The acf_get_meta_field only looks at the DB so this is where I think it initially goes wrong and because this method runs in strict mode it never calls acf_get_field which would resolve the field just fine.
Why does acf_get_meta_field only look at the DB if the local store has a mapping between field keys and names?
Why was this strict mode introduced? Did ACF stop supporting getting a value by name? That would explain a lot.
How I think this issue should be resolved:
acf_get_reference which is called by acf_get_meta_field should check the local store to map a name to a key and fall back to the DB when it can’t find one although I think that situation would trigger this new notice. So I wonder if fetching this info from the DB would be needed at all.
