Headers Already Sent Error

I had the same error.

The current version of the Search & Filter plugin breaks with the latest version of PHP (7.2.5). When I rolled back to an older version of PHP (5.6.36, 7.0.30, 7.1.18), this error went away.

Hopefully, the author will update the plugin to be PHP 7.2 compatible.

I got the plugin working in PHP 7.2 by editing the source code.

[search-filter.php]
//loop through all the query vars
foreach($wp_query->query as $key=>$val)

UPDATED–>
//loop through all the query vars
foreach((array) $wp_query->query as $key=>$val)

CREDIT (2nd answer):
https://stackoverflow.com/questions/2630013/invalid-argument-supplied-for-foreach

Thank you, @coffeehero. I made that fix, and all is well.

FWIW, it’s not just pre-7.2 versions of php that generate the error.

I echo your hope that the plugin author will update the plugin to fix the error.

I find the plugin very useful, especially for filtering categories and tags even without the search box. I’m in the midst of writing a blog article extolling the plugin’s virtues, and I’d like to be able to remove the disclaimer I feel a need to add, referencing the bug.