Lets break it down step by step:
if ($query->is_search && is_page_template('search')) {
There are 3 problems here
is_page_template
search.php isn’t a page template, that’s not how the search template is loaded. So this won’t work.
But if it did work, there’s a new problem. Functions such as is_page_template etc rely on the main query, but we’re in a pre_get_posts filter, you don’t know if that query has been set yet, or if you’re filtering that query or another.
So we need to:
- remove the
is_page_templatecheck, it doesn’t do what you think it does - Add an
$query->is_main_query()check so the filter doesn’t interfere with widgets and other queries
Methods vs member variables
if ($query->is_search
This doesn’t work, and should be generating PHP warnings for you. The problem is that is_search is a function/method not a variable, it should be:
if ( $query->is_search() && $query->is_main_query() ) {
But search.php?
WordPress decides which template is loaded based on the main query. If it’s the main query, and is_search is true, then search.php will be loaded.
Because of this, WordPress hasn’t decided which template to use when your filter happens. In fact, you can make WordPress change which template it loads by modifying the query variables. For example, if you unset all the variables, and tell it to load a single post, you won’t get search.php, or an archive at all, you’re likely to get single.php instead
What About Search Queries in Page Templates?
is_main_query will be false, so not an issue