Warning: Undefined array key "host"

[ainsleyclark]

I encountered an issue on my WordPress website where an ErrorException is thrown, displaying the following error message:

ErrorException
Warning: Undefined array key "host"

This error occurs in the canonical.php file on line 718 of the /wp-includes/ directory. Here is the relevant code snippet:

$compare_original = array( $original['host'], $original['path'] );

Additionally, the error stack trace includes the following information:

/wp-includes/canonical.php in redirect_canonical at line 718

https://core.trac.wordpress.org/ticket/60173

[SergeyBiryukov]

Hi there, welcome to WordPress Trac! Thanks for the ticket.

Just noting that there is an ongoing discussion on fixing these notices in #34353.

[ironprogrammer]

There have been several recent additional reports of this notice/warning, so I'd like to formally mark this as a duplicate to consolidate discussion and review of approaches to fix it over in #34353.