Error when searching for an empty string

I see. Tried it on two installations to proof it has something to do with RankMath itself.. (I suppose I had to do some more tests)

It looks like the error is triggered when the Polylang Extension is installed on the page. (Both installations where running on polylang…)

Both deactivating Polylang OR RankMath removes the error. There must be some incompability. I’ll also try to reach out to the Polylang Team.

A conditional check for is_search on line 106 at class-paper.php helps:
} elseif ( Post::is_simple_page() && !is_search() ) {

It looks like Post::is_simple_page() returns true on an empty search when Polylang is active

• This reply was modified 5 years ago by Bastian Fießinger.
• This reply was modified 5 years ago by Bastian Fießinger.
• This reply was modified 5 years ago by Bastian Fießinger.

I’m still texting with Polylang atm.
It looks like I found the malefactor.

Polylang sets the following query vars when searching for an empty string while a language is selected:

WP_Query->is_home is set to true
WP_Query->is_archive is set to false
WP_Query->is_tax is set to false

I’m waiting for a response from Polylang if i’m right but for me it looks like this might trigger the error.

Edit: Yep I am right with my assumption. Still waiting for Polylang but i tried commenting out this section and the error has been gone.

I think a conditional check if we’re on a search page in the get_simple_page_id() method that returns false might do the trick here.

	/**
	 * Get the ID of the current page.
	 *
	 * @return int The ID of the page.
	 */
	public static function get_simple_page_id() {
		/**
		 * Filter: Allow changing the default page ID. Short-circuit if 3rd party set page ID.
		 *
		 * @param unsigned int $page_id The default page id.
		 */
		$page_id = apply_filters( 'rank_math/pre_simple_page_id', false );
    
    if ( \is_search() && get_query_var( 's' ) == '' {
      return false;
    }
    
		if ( false !== $page_id ) {
			return $page_id;
		}

		if ( \is_singular() ) {
			return get_the_ID();
		}

		if ( self::is_posts_page() ) {
			return get_option( 'page_for_posts' );
		}

		if ( self::is_shop_page() ) {
			return self::get_shop_page_id();
		}

		/**
		 * Filter: Allow changing the default page ID.
		 *
		 * @param unsigned int $page_id The default page ID.
		 */
		return apply_filters( 'rank_math/simple_page_id', 0 );
	}

• This reply was modified 5 years ago by Bastian Fießinger.
• This reply was modified 5 years ago by Bastian Fießinger.
• This reply was modified 5 years ago by Bastian Fießinger.