From 6b224e3ac043009663be61c6646841c0fe45bf0a Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Wed, 9 Mar 2022 15:06:09 +0000
Subject: [PATCH] Canonical: Check if the URL scheme exists in
 `strip_fragment_from_url()`.

This avoids an "Undefined index" PHP notice when a schemeless URI is passed.

Props dd32, SergeyBiryukov.
Fixes #55333.

git-svn-id: https://develop.svn.wordpress.org/trunk@52833 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/canonical.php                 | 12 ++++--
 .../tests/canonical/stripFragmentFromUrl.php  | 40 +++++++++++++++++++
 2 files changed, 49 insertions(+), 3 deletions(-)
 create mode 100644 tests/phpunit/tests/canonical/stripFragmentFromUrl.php

diff --git a/src/wp-includes/canonical.php b/src/wp-includes/canonical.php
index 184fb756e8..0defa8227d 100644
--- a/src/wp-includes/canonical.php
+++ b/src/wp-includes/canonical.php
@@ -847,11 +847,17 @@ function _remove_qs_args_if_not_in_url( $query_string, array $args_to_check, $ur
  * @return string The altered URL.
  */
 function strip_fragment_from_url( $url ) {
-	$parsed_url = parse_url( $url );
+	$parsed_url = wp_parse_url( $url );
 
 	if ( ! empty( $parsed_url['host'] ) ) {
-		// This mirrors code in redirect_canonical(). It does not handle every case.
-		$url = $parsed_url['scheme'] . '://' . $parsed_url['host'];
+		$url = '';
+
+		if ( ! empty( $parsed_url['scheme'] ) ) {
+			$url = $parsed_url['scheme'] . ':';
+		}
+
+		$url .= '//' . $parsed_url['host'];
+
 		if ( ! empty( $parsed_url['port'] ) ) {
 			$url .= ':' . $parsed_url['port'];
 		}
diff --git a/tests/phpunit/tests/canonical/stripFragmentFromUrl.php b/tests/phpunit/tests/canonical/stripFragmentFromUrl.php
new file mode 100644
index 0000000000..053ad88528
--- /dev/null
+++ b/tests/phpunit/tests/canonical/stripFragmentFromUrl.php
@@ -0,0 +1,40 @@
+<?php
+
+/**
+ * @group canonical
+ * @group rewrite
+ * @group query
+ * @covers ::strip_fragment_from_url
+ */
+class Tests_Canonical_StripFragmentFromUrl extends WP_UnitTestCase {
+
+	/**
+	 * @dataProvider data_strip_fragment_from_url
+	 * @ticket 55333
+	 */
+	public function test_strip_fragment_from_url( $test_url, $expected ) {
+		$this->assertSame( $expected, strip_fragment_from_url( $test_url ) );
+	}
+
+	/**
+	 * Data provider for test_strip_fragment_from_url().
+	 *
+	 * @return array[] {
+	 *     Data to test with.
+	 *
+	 *     @type string $0 The test URL.
+	 *     @type string $1 The expected canonical URL.
+	 * }
+	 */
+	public function data_strip_fragment_from_url() {
+		return array(
+			array( '//example.com', '//example.com' ),
+			array( 'http://example.com', 'http://example.com' ),
+			array( 'https://example.com', 'https://example.com' ),
+			array( 'https://example.com/', 'https://example.com/' ),
+			array( 'https://example.com/?test', 'https://example.com/?test' ),
+			array( 'https://example.com/?#test', 'https://example.com/' ),
+			array( 'https://example.com/?#test#', 'https://example.com/' ),
+		);
+	}
+}