[WordPress] An example of how to avoid getting stuck in an infinite loop of events when using `save_post`.

acme-save-post-correct.php

<?php

class AcmeSavePost {
  
  public function __construct() {
    add_action( 'save_post', array( $this, 'modify_post_content' ) );
  }
  
  public function modify_post_content( $post_id ) {
  
    $post = array(
        'ID'       => $post_id,
        'content' => ''
      );
      
    remove_action( 'save_post', array( $this, 'modify_post_content' ) );
    wp_update_post( $post );
    add_action( 'save_post', array( $this, 'modify_post_content' ) );
    
  }
  
}

acme-save-post-incorrect.php

<?php

class AcmeSavePost {
  
  public function __construct() {
    add_action( 'save_post', array( $this, 'modify_post_content' ) );
  }
  
  public function modify_post_content( $post_id ) {
  
    $post = array(
        'ID'       => $post_id,
        'content'  => ''
      );
      
    wp_update_post( $post );
    
  }
  
}