From 5ca2a817abb025a01bf9a8056ed00c766f7e6eed Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Mon, 16 Aug 2021 20:17:57 +0000
Subject: [PATCH] Code Modernization: Check the return type of `parse_url()` in
 `WP::parse_request()`.
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As per the PHP manual:
> If the `component` parameter is omitted, an associative array is returned.
> If the `component` parameter is specified, `parse_url()` returns a string (or an int, in the case of `PHP_URL_PORT`) instead of an array. If the requested component doesn't exist within the given URL, `null` will be returned.

Reference: [https://www.php.net/manual/en/function.parse-url.php#refsect1-function.parse-url-returnvalues PHP Manual: parse_url(): Return Values]

In this case, `parse_url()` is called with the `PHP_URL_PATH` as `$component`. This will return `null` in the majority of cases, as – exсept for subdirectory-based sites – `home_url()` returns a URL without the trailing slash, like `http://example.org`.

The return value of `parse_url()` was subsequently passed to `trim()`, leading to a `trim(): Passing null to parameter #1 ($string) of type string is deprecated` notice on PHP 8.1.

Fixed by adjusting the logic flow to:
* Only pass the return value of `parse_url()` to follow-on functions if it makes sense, i.e. if it isn't `null`, nor an empty string.
* Preventing calls to `preg_replace()` and `trim()` further down in the function logic flow, when `preg_replace()`/`trim()` would have nothing to do anyhow.

Follow-up to [25617].

Props jrf, hellofromTonya, SergeyBiryukov.
See #53635.
Built from https://develop.svn.wordpress.org/trunk@51622


git-svn-id: http://core.svn.wordpress.org/trunk@51228 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/class-wp.php | 24 ++++++++++++++++--------
 wp-includes/version.php  |  2 +-
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/wp-includes/class-wp.php b/wp-includes/class-wp.php
index 8c7c48b3b2..770df083e7 100644
--- a/wp-includes/class-wp.php
+++ b/wp-includes/class-wp.php
@@ -170,8 +170,13 @@ class WP {
 
 			list( $req_uri ) = explode( '?', $_SERVER['REQUEST_URI'] );
 			$self            = $_SERVER['PHP_SELF'];
-			$home_path       = trim( parse_url( home_url(), PHP_URL_PATH ), '/' );
-			$home_path_regex = sprintf( '|^%s|i', preg_quote( $home_path, '|' ) );
+
+			$home_path       = parse_url( home_url(), PHP_URL_PATH );
+			$home_path_regex = '';
+			if ( is_string( $home_path ) && '' !== $home_path ) {
+				$home_path       = trim( $home_path, '/' );
+				$home_path_regex = sprintf( '|^%s|i', preg_quote( $home_path, '|' ) );
+			}
 
 			/*
 			 * Trim path info from the end and the leading home path from the front.
@@ -180,14 +185,17 @@ class WP {
 			 */
 			$req_uri  = str_replace( $pathinfo, '', $req_uri );
 			$req_uri  = trim( $req_uri, '/' );
-			$req_uri  = preg_replace( $home_path_regex, '', $req_uri );
-			$req_uri  = trim( $req_uri, '/' );
-			$pathinfo = trim( $pathinfo, '/' );
-			$pathinfo = preg_replace( $home_path_regex, '', $pathinfo );
 			$pathinfo = trim( $pathinfo, '/' );
 			$self     = trim( $self, '/' );
-			$self     = preg_replace( $home_path_regex, '', $self );
-			$self     = trim( $self, '/' );
+
+			if ( ! empty( $home_path_regex ) ) {
+				$req_uri  = preg_replace( $home_path_regex, '', $req_uri );
+				$req_uri  = trim( $req_uri, '/' );
+				$pathinfo = preg_replace( $home_path_regex, '', $pathinfo );
+				$pathinfo = trim( $pathinfo, '/' );
+				$self     = preg_replace( $home_path_regex, '', $self );
+				$self     = trim( $self, '/' );
+			}
 
 			// The requested permalink is in $pathinfo for path info requests and
 			// $req_uri for other requests.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8dbc24083f..cf2bc62107 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51619';
+$wp_version = '5.9-alpha-51622';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.