How to stop execution of a function via add_action hook?

Question

I have the following functions:

function test($post_id){

do_action('test_action',$post_id);

echo $post_id;

}

add_action('test_action',function($post_id){

if ( $post_id == 2 ) //Stop test function execution

}

Using the function hooked to add_action, how to stop the execution of test() function without adding any code to test(). In the above example, if $post_id == 2 , the echo $post_id; code should not run in test().

Answer 1

The usual way to add an action hook is more like this:

// ... some other code
do_action( 'my_action', $post_id );

// ...elsewhere
add_action( 'my_action', 'wpse405965_function' );
/**
 * Function hooked to my_action
 *
 * @param int $post_id The post ID.
 */
function wpse405965_function( $post_id ) {
    if ( 2 !== $post_id ) {
        echo $post_id;
    }
}

The way you've wrapped the do_action() inside a function confuses me. It seems extraneous.

Reference

• add_action()

Answer 2

You have both registered and called action hooks, did you know you could do the same with filters? This answer uses a filter to call a return; statement as the community suggested, to do an early return and stop executing the rest of test function body (echo in your case).

function test($post_id)
{
    do_action('test_action', $post_id);

    if ( apply_filters('wpse_405965_stop_execution', false) )
        return;

    echo $post_id;
}

add_action('test_action', function($post_id)
{
    if ( $post_id == 2 ) // Stop test function execution
        add_filter('wpse_405965_stop_execution', '__return_true');
});