Ticket #33887: 33887-alternative.diff

src/wp-includes/link-template.php

@@ -3370 +3370 @@
 function set_url_scheme( $url, $scheme = null ) {
         $orig_scheme = $scheme;
 
+        // if we're switched on multisite and no specific scheme is requested, try to detect it from the URL
+        if ( is_multisite() && ! empty( $GLOBALS['_wp_switched_stack'] ) ) {
+                if ( ! $scheme
+                        || ( 'admin' === $scheme || 'login' === $scheme || 'login_post' === $scheme || 'rpc' === $scheme ) && ! force_ssl_admin()
+                        || 'http' !== $scheme && 'https' !== $scheme && 'relative' !== $scheme
+                ) {
+                        if ( 0 === strpos( $url, 'https://' ) ) {
+                                $scheme = 'https';
+                        } elseif ( 0 === strpos( $url, 'http://' ) ) {
+                                $scheme = 'http';
+                        }
+                }
+        }
+
         if ( ! $scheme ) {
                 $scheme = is_ssl() ? 'https' : 'http';
         } elseif ( $scheme === 'admin' || $scheme === 'login' || $scheme === 'login_post' || $scheme === 'rpc' ) {