From 80bd8ac220ab0ac10afc2e19fcbab1ba2368ec7c Mon Sep 17 00:00:00 2001
From: Pascal Birchler <swissspidy@git.wordpress.org>
Date: Wed, 27 Sep 2017 08:35:16 +0000
Subject: [PATCH] Embeds: Maintain switched state when embedding a post on
 Multisite.

Props bor0.
Fixes #40673.


git-svn-id: https://develop.svn.wordpress.org/trunk@41606 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/embed.php               |  5 ++++-
 tests/phpunit/tests/oembed/wpOembed.php | 29 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/embed.php b/src/wp-includes/embed.php
index d83e8f510d..6040004bac 100644
--- a/src/wp-includes/embed.php
+++ b/src/wp-includes/embed.php
@@ -1071,6 +1071,8 @@ function the_embed_site_title() {
  *                     Null if the URL does not belong to the current site.
  */
 function wp_filter_pre_oembed_result( $result, $url, $args ) {
+	$switched_blog = false;
+
 	if ( is_multisite() ) {
 		$url_parts = wp_parse_args( wp_parse_url( $url ), array(
 			'host'   => '',
@@ -1094,6 +1096,7 @@ function wp_filter_pre_oembed_result( $result, $url, $args ) {
 
 		if ( $site && (int) $site->blog_id !== get_current_blog_id() ) {
 			switch_to_blog( $site->blog_id );
+			$switched_blog = true;
 		}
 	}
 
@@ -1111,7 +1114,7 @@ function wp_filter_pre_oembed_result( $result, $url, $args ) {
 	$data = get_oembed_response_data( $post_id, $width );
 	$data = _wp_oembed_get_object()->data2html( (object) $data, $url );
 
-	if ( is_multisite() && ms_is_switched() ) {
+	if ( $switched_blog ) {
 		restore_current_blog();
 	}
 
diff --git a/tests/phpunit/tests/oembed/wpOembed.php b/tests/phpunit/tests/oembed/wpOembed.php
index 767655c873..d8d346de11 100644
--- a/tests/phpunit/tests/oembed/wpOembed.php
+++ b/tests/phpunit/tests/oembed/wpOembed.php
@@ -171,4 +171,33 @@ class Tests_WP_oEmbed extends WP_UnitTestCase {
 		$this->assertNotNull( $this->pre_oembed_result_filtered );
 		$this->assertEquals( $this->pre_oembed_result_filtered, $actual );
 	}
+
+	/**
+	 * @ticket 40673
+	 * @group multisite
+	 * @group ms-required
+	 */
+	public function test_wp_filter_pre_oembed_result_multisite_preserves_switched_state() {
+		$user_id = self::factory()->user->create();
+
+		$blog_id = self::factory()->blog->create( array( 'user_id' => $user_id ) );
+		switch_to_blog( $blog_id );
+
+		$expected_stack = $GLOBALS['_wp_switched_stack'];
+
+		$post_id   = self::factory()->post->create();
+		$permalink = get_permalink( $post_id );
+
+		add_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+		$actual = $this->oembed->get_html( $permalink );
+		remove_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+
+		$actual_stack = $GLOBALS['_wp_switched_stack'];
+
+		restore_current_blog();
+
+		$this->assertNotNull( $this->pre_oembed_result_filtered );
+		$this->assertEquals( $this->pre_oembed_result_filtered, $actual );
+		$this->assertSame( $expected_stack, $actual_stack );
+	}
 }