Widgets: when passing a string arg value to dynamic_sidebar(), don't reset $index when the arg's sanitized value matches the sanitized name of a sidebar.

Adds unit test.

Props tyxla, fjarrett.
Fixes #23423.


git-svn-id: https://develop.svn.wordpress.org/trunk@34465 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/widgets.php

@@ -293,4 +293,21 @@ class Tests_Widgets extends WP_UnitTestCase {
 		$this->assertArrayNotHasKey( 2, $option_value );
 	}
 
+	/**
+	 * @ticket 23423
+	 */
+	function test_dynamic_sidebar_id_special_characters() {
+		wp_widgets_init();
+		register_sidebar( array(
+			'name' => 'Sidebar 2',
+			'id' => 'sidebar-2',
+		) );
+
+		ob_start();
+		$result = dynamic_sidebar( 'Sidebar 1' );
+		ob_end_clean();
+		 
+		$this->assertFalse( $result );
+	}
+
 }