Advanced Custom Fields Multilingual (ACFML): PHP Warning - Attempt to read property "post_content" on null

Overview of the issue

Under some scenarios, Advanced Custom Fields Multilingual (ACFML) plugin may run into a PHP warning when utilizing ACF fields:

Attempt to read property "post_content" on null in plugins .../acfml/classes/class-wpml-acf-repeater-shuffle.php on line 249

Workaround

Please, make sure of having a full backup of your site before proceeding.

• Open …/acfml/classes/class-wpml-acf-repeater-shuffle.php file.
• Look for line 244.
• Replace:

  	private function isChildOfRepeaterField( $key, $postId ) {
  		$acfFieldObject = get_field_object( $key, $postId );
  		if ( isset( $acfFieldObject['parent'] )
  			 && $acfFieldObject['parent'] > 0 ) {
  			$fieldParent        = get_post( $acfFieldObject['parent'] );
  			$fieldParentContent = maybe_unserialize( $fieldParent->post_content );
  			if ( isset( $fieldParentContent['type'] ) && 'repeater' === $fieldParentContent['type'] ) {
  				return true;
  			}
  		}
  		return false;
  	}
  

• With:

  private function isChildOfRepeaterField( $key, $postId ) {
      $acfFieldObject = get_field_object( $key, $postId );
      if ( isset( $acfFieldObject['parent'] ) ) {
          if ( is_numeric( $acfFieldObject['parent'] ) && $acfFieldObject['parent'] > 0 ) {
              $fieldParent = get_post( $acfFieldObject['parent'], $postId );
              if ( $fieldParent ) {
                  $fieldParentContent = maybe_unserialize( $fieldParent->post_content );
                  if ( isset( $fieldParentContent['type'] ) && 'repeater' === $fieldParentContent['type'] ) {
                      return true;
                  }
              }
          } elseif ( is_string( $acfFieldObject['parent'] ) ) {
              $fieldParent = get_field_object( $acfFieldObject['parent'], $postId );
              if ( isset( $fieldParent['type'] ) && 'repeater' === $fieldParent['type'] ) {
                  return true;
              }
          }
      }
      return false;
  }