如何修复这些非法字符串偏移警告？

Question

Context: On one of the sites where my WordPress plugin is installed I'm seeing a series of PHP warnings, but I'm not entirely sure why this is happening. I'm hoping someone here can help me figure out how to solve this warning.

Code Sample:

function my_function( $array ) {

   if ( ! isset( $array['where'] ) ) { $array['where'] = 'after'; }
   if ( ! isset( $array['echo'] ) ) { $array['echo'] = false; }
   if ( ! isset( $array['content'] ) ) { $array['content'] = false; }

   $array['shortcode'] = true;
   $array['devs'] = true;
   return social_warfare( $array );
}

add_shortcode( 'my_shortcode', 'my_function' );

The Warning:

Warning: Illegal string offset 'where' in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 14

Warning: Illegal string offset 'echo' in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 15

Warning: Cannot assign an empty string to a string offset in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 15

Warning: Illegal string offset 'content' in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 16

Warning: Cannot assign an empty string to a string offset in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 16

Warning: Illegal string offset 'shortcode' in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 18

Warning: Illegal string offset 'devs' in /home/playitda/public_html/domain.com/wp-content/plugins/my_plugin/functions/frontend-output/shortcodes.php on line 19

For some reason, it's throwing a warning every time it encounters one of the indices in the array. How do I fix this? Thanks!

Answer 1

The usage of the function is_array() in the beginning of your function can give you the insurance, that, if someone pass you something else than an array, the variable is reinitialised as an empty array.

Unsetting or nulling it before doing that is useless, because, as of PHP 5.3, PHP does have a garbage collector mechanism.

/**
 * @params array $array
 */
function my_function( $array ) {
   if ( ! is_array ( $array ) ) { $array = [] };
   /**
    * Or, if you don't like the short array notation:
    * if ( ! is_array ( $array ) ) { $array = array(); };
    */

   if ( ! isset( $array['where'] ) ) { $array['where'] = 'after'; }
   if ( ! isset( $array['echo'] ) ) { $array['echo'] = false; }
   if ( ! isset( $array['content'] ) ) { $array['content'] = false; }

   $array['shortcode'] = true;
   $array['devs'] = true;
   return social_warfare( $array );
}

add_shortcode( 'my_shortcode', 'my_function' );