Testing script for WordPress Trac ticket 28020

28020.php

<?php

namespace Test\trac28020;

/**
 * Add this file into the wp-content/mu-plugins folder.
 */
add_action( 'init', function() {
	// Bail out if in the backend (Admin area). Only want to run this in the frontend.
	if ( is_admin() ) {
		return;
	}

	$user_id     = get_current_user_id();
	$get_user_by = get_user_by( 'id', $user_id );
	// Run only if you're logged in.
	if ( false === $get_user_by ) {
		return;
	}

	echo "<h2>Current user => you</h2>";
	print_results( $get_user_by );

	echo "<h2>Changing to a different user</h2>";

	// UID for this demo should be a subscriber
	$user_id = 2;
	wp_set_current_user( $user_id );


	// $GLOBALS['current_user'] now contains a WP_User instance
	$get_user_by   = get_user_by( 'id', $user_id );
	$from_userdata = get_userdata( $user_id );

	print_results( $get_user_by, $from_userdata );

	echo "<h2>Changing different user to be an admin</h2>";

	// $from_userdata now also contains a WP_User instance, but not the same one

	// Fun times with desynchronisation:
	$from_userdata->set_role( 'administrator' );

	print_results( $get_user_by, $from_userdata );

	// Restore the user back to subscriber.
	$from_userdata->set_role( 'subscriber' );
	exit;
});

function print_results( $get_user_by, $from_userdata = null ) {
	$user_id = get_current_user_id();

	echo "<p>Current user ID is: {$user_id}</p>";
	printf( '<p>Has admin rights? %s</p>', current_user_can('administrator' ) ? '👍': '👎' );

	?>
	<table>
		<thead>
			<th>Object source</th>
			<th>Object ID</th>
		</thead>
		<tbody>
			<tr>
				<td>get_user_by()</td>
				<td><?php echo spl_object_id( $get_user_by ); ?></td>
			</tr>
			<tr>
				<td>$GLOBALS['current_user']</td>
				<td><?php echo spl_object_id( $GLOBALS['current_user'] ); ?></td>
			</tr>
			<?php if ( null !== $from_userdata ) : ?>
			<tr>
				<td>get_userdata()</td>
				<td><?php echo spl_object_id( $from_userdata ); ?></td>
			</tr>
			<?php endif; ?>
		</tbody>
	</table>
	<?php
}