Retrieve an array of active and valid plugin files.

While upgrading or installing WordPress, no plugins are returned.

The default directory is `wp-content/plugins`. To change the default
directory manually, define `WP_PLUGIN_DIR` and `WP_PLUGIN_URL`
in `wp-config.php`.

function wp_get_active_and_valid_plugins() {
	$plugins        = array();
	$active_plugins = (array) get_option( 'active_plugins', array() );

	// Check for hacks file if the option is enabled.
	if ( get_option( 'hack_file' ) && file_exists( ABSPATH . 'my-hacks.php' ) ) {
		_deprecated_file( 'my-hacks.php', '1.5.0' );
		array_unshift( $plugins, ABSPATH . 'my-hacks.php' );
	}

	if ( empty( $active_plugins ) || wp_installing() ) {
		return $plugins;
	}

	$network_plugins = is_multisite() ? wp_get_active_network_plugins() : false;

	foreach ( $active_plugins as $plugin ) {
		if ( ! validate_file( $plugin )                     // $plugin must validate as file.
			&& '.php' === substr( $plugin, -4 )             // $plugin must end with '.php'.
			&& file_exists( WP_PLUGIN_DIR . '/' . $plugin ) // $plugin must exist.
			// Not already included as a network plugin.
			&& ( ! $network_plugins || ! in_array( WP_PLUGIN_DIR . '/' . $plugin, $network_plugins, true ) )
			) {
			$plugins[] = WP_PLUGIN_DIR . '/' . $plugin;
		}
	}

	/*
	 * Remove plugins from the list of active plugins when we're on an endpoint
	 * that should be protected against WSODs and the plugin is paused.
	 */
	if ( wp_is_recovery_mode() ) {
		$plugins = wp_skip_paused_plugins( $plugins );
	}

	return $plugins;
}