get submitted form's post_id from outside the loop PHP - php

Question

I am working on an app that has a post form that matches up adoption mentors with mentees.
This is in Wordpress/PHP/MySQL/ACF (Advanced Custom Field).
After the form has been submitted, I am unable to get the post_id for that post so I can save the ACF field "title" for the screen that lists all the matches.
Do I need to retrieve that form's $post_id when I'm "outside the loop"? And how do I do that?
function match_post_title_auto( $post_id ) {
// get mentor & new mentee user array
$mentee = get_field('match_mentee', $post_id);
$mentor = get_field('match_mentor', $post_id);
$title = ' Mentor: ' . $mentor['display_name'] . ' and Mentee: ' . $mentee['display_name'];
$postdata = array(
'ID' => $post_id,
'post_title' => $title,
'post_type' => 'match'
);
wp_update_post( $postdata );
return $value;
}
var_dump($post_id); //returns NULL
//what do I put here to get that `post_id`? Thanks!
add_action('acf/save_post', 'match_post_title_auto', 10, 1);

Answer 1

The acf/save_post hook only passes the $post_id as single parameter. You have 3 parameters in your callback. https://www.advancedcustomfields.com/resources/acf-save_post/. Also, you need to have a priority higher than 10 to get the updated values from your post.
function match_post_title_auto( $post_id ) {
// do stuff
}
add_filter('acf/save_post', 'match_post_title_auto', 20 );

Answer 2

you are trying to catch the values by filter hook. Actually you need action hook and 1 parameter only. like this:
add_action('acf/save_post', 'match_post_title_auto', 10, 1);
Hope it will work.
for more information, check the standard documentation:
https://www.advancedcustomfields.com/resources/acf-save_post/