Prevent redirect loops in WordPress

mu-plugin-prevent-redirect-loop.php

<?php
/**
 * Plugin Name: Prevent Redirect Loop
 * Description: Prevent redirect loops if user adds a redirect to the same page in Yoast SEO Premium or other plugins.
 * Version:     1.0.0
 * Author:      Remon Pel
 */

// Prevent redirect loops.
add_filter(
	'wp_redirect',
	function ( $location ) {
		// phpcs:disable WordPress.Security.ValidatedSanitizedInput.MissingUnslash
		// phpcs:disable WordPress.Security.ValidatedSanitizedInput.InputNotSanitized

		// get the current request.
		$request = ! empty( $_SERVER['REQUEST_URI'] ) ? trim( $_SERVER['REQUEST_URI'], '/' ) : '/';
		// add the current GET params to the request.
		$request .= ! empty( $_SERVER['QUERY_STRING'] ) ? '?' . trim( $_SERVER['QUERY_STRING'] ) : '';

		// phpcs:enable WordPress.Security.ValidatedSanitizedInput.MissingUnslash
		// phpcs:enable WordPress.Security.ValidatedSanitizedInput.InputNotSanitized

		// use wp_parse_url to get the path and the GET params of both the request and the location.
		$request_parsed          = wp_parse_url( $request );
		$location_parsed         = wp_parse_url( $location );
		$request_parsed['path']  = trim( $request_parsed['path'], '/' );
		$location_parsed['path'] = trim( $location_parsed['path'], '/' );

		// if the request and the location are the same, we have a redirect loop.
		if ( $request_parsed['path'] === $location_parsed['path'] && $request_parsed['query'] === $location_parsed['query'] ) {
			header( 'X-Redirect-Loop-Prevented-By:' . basename( __FILE__ ) );

			return false;
		}

		return $location;
	},
	10,
	1
);