Multisite: Use `to_array()` method on `WP_Site` objects in `wp_get_sites()`

When an object with private properties is cast directly to an array, those properties are no longer available with their original keys.

Props @flixos90.
See #36717.


git-svn-id: https://develop.svn.wordpress.org/trunk@37667 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/ms-deprecated.php

@@ -506,7 +506,8 @@ function wp_get_sites( $args = array() ) {
 	$results = array();
 
 	foreach ( $_sites as $_site ) {
-		$results[] = (array) get_site( $_site );
+		$_site = get_site( $_site );
+		$results[] = $_site->to_array();
 	}
 
 	return $results;

tests/phpunit/tests/multisite/wpGetSites.php

@@ -3,6 +3,7 @@
 if ( is_multisite() ) :
 
 /**
+ * @group wp-get-site
  * @group ms-site
  * @group multisite
  */
@@ -31,6 +32,32 @@ class Tests_Multisite_WP_Get_Sites extends WP_UnitTestCase {
 		wp_update_network_site_counts();
 	}
 
+	/**
+	 * @expectedDeprecated wp_get_sites
+	 */
+	public function test_wp_get_sites_site_is_expected_array() {
+
+		$keys = array(
+			'blog_id',
+			'site_id',
+			'domain',
+			'path',
+			'registered',
+			'last_updated',
+			'public',
+			'archived',
+			'mature',
+			'spam',
+			'deleted',
+			'lang_id'
+		);
+		$sites = wp_get_sites();
+
+		$missing_keys = array_diff_key( array_flip( $keys ), $sites[0] );
+
+		$this->assertEquals( array(), $missing_keys, 'Keys are missing from site arrays.' );
+	}
+
 	/**
 	 * @expectedDeprecated wp_get_sites
 	 * @dataProvider data_wp_get_sites