TGM\TGM_Plugin_Activation

Complexity

Total Complexity

266

Size/Duplication

Total Lines	2102
Duplicated Lines	2.09 %

Coupling/Cohesion

Components	1
Dependencies	2

Importance

Changes

0

59 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	19	1
A	__set()	0	3	1
A	__get()	0	3	1
D	init()	0	140	10
A	load_textdomain()	0	14	4
A	correct_plugin_mofile()	0	7	2
B	overload_textdomain_mofile()	0	15	6
B	add_plugin_action_link_filters()	0	15	5
A	filter_plugin_action_links_activate()	0	5	1
A	filter_plugin_action_links_deactivate()	0	5	1
A	filter_plugin_action_links_update()	0	10	1
A	admin_init()	0	20	4
A	thickbox()	0	5	2
A	admin_menu()	0	20	2
A	add_admin_menu()	0	11	3
C	install_plugins_page()	0	43	8
F	do_plugin_install()	0	142	25
B	inject_update_info()	0	26	6
C	maybe_adjust_source_dir()	20	61	15
C	activate_single_plugin()	18	50	9
F	notices()	0	126	34
C	create_user_action_links_for_notice()	0	47	8
A	get_admin_notice_class()	0	13	4
A	display_settings_errors()	0	12	3
A	dismiss()	0	5	3
C	register()	0	52	9
A	get_plugin_source_type()	0	9	4
A	sanitize_key()	0	14	1
B	config()	0	25	4
A	actions()	0	8	2
A	flush_plugins_cache()	0	3	1
B	populate_file_path()	0	10	5
A	_get_plugin_basename_from_slug()	0	11	3
A	_get_plugin_data_from_name()	0	9	4
A	get_download_url()	0	14	4
A	get_wp_repo_download_url()	0	10	3
B	get_plugins_api()	0	29	4
B	get_info_link()	0	30	4
A	is_tgmpa_page()	0	3	2
B	is_core_update_page()	0	21	7
A	get_tgmpa_url()	0	18	3
A	get_tgmpa_status_url()	0	8	1
A	is_tgmpa_complete()	0	11	4
A	is_plugin_installed()	0	5	1
A	is_plugin_active()	0	3	3
A	can_plugin_update()	0	15	4
A	is_plugin_updatetable()	0	7	3
A	can_plugin_activate()	0	3	2
A	get_installed_version()	0	9	2
A	does_plugin_require_update()	0	6	1
A	does_plugin_have_update()	3	18	4
A	get_upgrade_notice()	3	14	3
A	get_plugins()	0	7	2
A	update_dismiss()	0	3	1
B	force_activation()	0	13	5
B	force_deactivation()	0	18	5
A	show_tgmpa_version()	0	11	1
A	admin_css()	0	12	2
A	get_instance()	0	7	3

<?php
	
	namespace TGM;
	
	/**
	 * Automatic plugin installation and activation library.
	 *
	 * Creates a way to automatically install and activate plugins from within themes.
	 * The plugins can be either bundled, downloaded from the WordPress
	 * Plugin Repository or downloaded from another external source.
	 *
	 * @since 1.0.0
	 *
	 * @package TGM-Plugin-Activation
	 * @author  Thomas Griffin
	 * @author  Gary Jones
	 */
	class TGM_Plugin_Activation {
		/**
		 * TGMPA version number.
		 *
		 * @since 2.5.0
		 *
		 * @const string Version number.
		 */
		const TGMPA_VERSION = '2.6.2';

		/**
		 * Regular expression to test if a URL is a WP plugin repo URL.
		 *
		 * @const string Regex.
		 *
		 * @since 2.5.0
		 */
		const WP_REPO_REGEX = '|^http[s]?://wordpress\.org/(?:extend/)?plugins/|';

		/**
		 * Arbitrary regular expression to test if a string starts with a URL.
		 *
		 * @const string Regex.
		 *
		 * @since 2.5.0
		 */
		const IS_URL_REGEX = '|^http[s]?://|';

		/**
		 * Holds a copy of itself, so it can be referenced by the class name.
		 *
		 * @since 1.0.0
		 *
		 * @var TGM_Plugin_Activation
		 */
		public static $instance;

		/**
		 * Holds arrays of plugin details.
		 *
		 * @since 1.0.0
		 * @since 2.5.0 the array has the plugin slug as an associative key.
		 *
		 * @var array
		 */
		public $plugins = array();

		/**
		 * Holds arrays of plugin names to use to sort the plugins array.
		 *
		 * @since 2.5.0
		 *
		 * @var array
		 */
		protected $sort_order = array();

		/**
		 * Whether any plugins have the 'force_activation' setting set to true.
		 *
		 * @since 2.5.0
		 *
		 * @var bool
		 */
		protected $has_forced_activation = false;

		/**
		 * Whether any plugins have the 'force_deactivation' setting set to true.
		 *
		 * @since 2.5.0
		 *
		 * @var bool
		 */
		protected $has_forced_deactivation = false;

		/**
		 * Name of the unique ID to hash notices.
		 *
		 * @since 2.4.0
		 *
		 * @var string
		 */
		public $id = 'tgmpa';

		/**
		 * Name of the query-string argument for the admin page.
		 *
		 * @since 1.0.0
		 *
		 * @var string
		 */
		protected $menu = 'tgmpa-install-plugins';

		/**
		 * Parent menu file slug.
		 *
		 * @since 2.5.0
		 *
		 * @var string
		 */
		public $parent_slug = 'themes.php';

		/**
		 * Capability needed to view the plugin installation menu item.
		 *
		 * @since 2.5.0
		 *
		 * @var string
		 */
		public $capability = 'edit_theme_options';

		/**
		 * Default absolute path to folder containing bundled plugin zip files.
		 *
		 * @since 2.0.0
		 *
		 * @var string Absolute path prefix to zip file location for bundled plugins. Default is empty string.
		 */
		public $default_path = '';

		/**
		 * Flag to show admin notices or not.
		 *
		 * @since 2.1.0
		 *
		 * @var boolean
		 */
		public $has_notices = true;

		/**
		 * Flag to determine if the user can dismiss the notice nag.
		 *
		 * @since 2.4.0
		 *
		 * @var boolean
		 */
		public $dismissable = true;

		/**
		 * Message to be output above nag notice if dismissable is false.
		 *
		 * @since 2.4.0
		 *
		 * @var string
		 */
		public $dismiss_msg = '';

		/**
		 * Flag to set automatic activation of plugins. Off by default.
		 *
		 * @since 2.2.0
		 *
		 * @var boolean
		 */
		public $is_automatic = false;

		/**
		 * Optional message to display before the plugins table.
		 *
		 * @since 2.2.0
		 *
		 * @var string Message filtered by wp_kses_post(). Default is empty string.
		 */
		public $message = '';

		/**
		 * Holds configurable array of strings.
		 *
		 * Default values are added in the constructor.
		 *
		 * @since 2.0.0
		 *
		 * @var array
		 */
		public $strings = array();

		/**
		 * Holds the version of WordPress.
		 *
		 * @since 2.4.0
		 *
		 * @var int
		 */
		public $wp_version;

		/**
		 * Holds the hook name for the admin page.
		 *
		 * @since 2.5.0
		 *
		 * @var string
		 */
		public $page_hook;

		/**
		 * Adds a reference of this object to $instance, populates default strings,
		 * does the tgmpa_init action hook, and hooks in the interactions to init.
		 *
		 * {@internal This method should be `protected`, but as too many TGMPA implementations
		 * haven't upgraded beyond v2.3.6 yet, this gives backward compatibility issues.
		 * Reverted back to public for the time being.}}
		 *
		 * @since 1.0.0
		 *
		 * @see TGM_Plugin_Activation::init()
		 */
		public function __construct() {
			// Set the current WordPress version.
			$this->wp_version = $GLOBALS['wp_version'];

			// Announce that the class is ready, and pass the object (for advanced use).
			do_action_ref_array( 'tgmpa_init', array( $this ) );

			/*
			 * Load our text domain and allow for overloading the fall-back file.
			 *
			 * {@internal IMPORTANT! If this code changes, review the regex in the custom TGMPA
			 * generator on the website.}}
			 */
			add_action( 'init', array( $this, 'load_textdomain' ), 5 );
			add_filter( 'load_textdomain_mofile', array( $this, 'overload_textdomain_mofile' ), 10, 2 );

			// When the rest of WP has loaded, kick-start the rest of the class.
			add_action( 'init', array( $this, 'init' ) );
		}

		/**
		 * Magic method to (not) set protected properties from outside of this class.
		 *
		 * {@internal hackedihack... There is a serious bug in v2.3.2 - 2.3.6  where the `menu` property
		 * is being assigned rather than tested in a conditional, effectively rendering it useless.
		 * This 'hack' prevents this from happening.}}
		 *
		 * @see https://github.com/TGMPA/TGM-Plugin-Activation/blob/2.3.6/tgm-plugin-activation/class-tgm-plugin-activation.php#L1593
		 *
		 * @since 2.5.2
		 *
		 * @param string $name  Name of an inaccessible property.
		 * @param mixed  $value Value to assign to the property.
		 * @return void  Silently fail to set the property when this is tried from outside of this class context.
		 *               (Inside this class context, the __set() method if not used as there is direct access.)
		 */
		public function __set( $name, $value ) {
			return;
		}

		/**
		 * Magic method to get the value of a protected property outside of this class context.
		 *
		 * @since 2.5.2
		 *
		 * @param string $name Name of an inaccessible property.
		 * @return mixed The property value.
		 */
		public function __get( $name ) {
			return $this->{$name};
		}

		/**
		 * Initialise the interactions between this class and WordPress.
		 *
		 * Hooks in three new methods for the class: admin_menu, notices and styles.
		 *
		 * @since 2.0.0
		 *
		 * @see TGM_Plugin_Activation::admin_menu()
		 * @see TGM_Plugin_Activation::notices()
		 * @see TGM_Plugin_Activation::styles()
		 */
		public function init() {
			/**
			 * By default TGMPA only loads on the WP back-end and not in an Ajax call. Using this filter
			 * you can overrule that behaviour.
			 *
			 * @since 2.5.0
			 *
			 * @param bool $load Whether or not TGMPA should load.
			 *                   Defaults to the return of `is_admin() && ! defined( 'DOING_AJAX' )`.
			 */
			if ( true !== apply_filters( 'tgmpa_load', ( is_admin() && ! defined( 'DOING_AJAX' ) ) ) ) {
				return;
			}

			// Load class strings.
			$this->strings = array(
				'page_title'                      => __( 'Install Required Plugins', 'tgmpa' ),
				'menu_title'                      => __( 'Install Plugins', 'tgmpa' ),
				/* translators: %s: plugin name. */
				'installing'                      => __( 'Installing Plugin: %s', 'tgmpa' ),
				/* translators: %s: plugin name. */
				'updating'                        => __( 'Updating Plugin: %s', 'tgmpa' ),
				'oops'                            => __( 'Something went wrong with the plugin API.', 'tgmpa' ),
				/* translators: 1: plugin name(s). */
				'notice_can_install_required'     => _n_noop(
					'This theme requires the following plugin: %1$s.',
					'This theme requires the following plugins: %1$s.',
					'tgmpa'
				),
				/* translators: 1: plugin name(s). */
				'notice_can_install_recommended'  => _n_noop(
					'This theme recommends the following plugin: %1$s.',
					'This theme recommends the following plugins: %1$s.',
					'tgmpa'
				),
				/* translators: 1: plugin name(s). */
				'notice_ask_to_update'            => _n_noop(
					'The following plugin needs to be updated to its latest version to ensure maximum compatibility with this theme: %1$s.',
					'The following plugins need to be updated to their latest version to ensure maximum compatibility with this theme: %1$s.',
					'tgmpa'
				),
				/* translators: 1: plugin name(s). */
				'notice_ask_to_update_maybe'      => _n_noop(
					'There is an update available for: %1$s.',
					'There are updates available for the following plugins: %1$s.',
					'tgmpa'
				),
				/* translators: 1: plugin name(s). */
				'notice_can_activate_required'    => _n_noop(
					'The following required plugin is currently inactive: %1$s.',
					'The following required plugins are currently inactive: %1$s.',
					'tgmpa'
				),
				/* translators: 1: plugin name(s). */
				'notice_can_activate_recommended' => _n_noop(
					'The following recommended plugin is currently inactive: %1$s.',
					'The following recommended plugins are currently inactive: %1$s.',
					'tgmpa'
				),
				'install_link'                    => _n_noop(
					'Begin installing plugin',
					'Begin installing plugins',
					'tgmpa'
				),
				'update_link'                     => _n_noop(
					'Begin updating plugin',
					'Begin updating plugins',
					'tgmpa'
				),
				'activate_link'                   => _n_noop(
					'Begin activating plugin',
					'Begin activating plugins',
					'tgmpa'
				),
				'return'                          => __( 'Return to Required Plugins Installer', 'tgmpa' ),
				'dashboard'                       => __( 'Return to the Dashboard', 'tgmpa' ),
				'plugin_activated'                => __( 'Plugin activated successfully.', 'tgmpa' ),
				'activated_successfully'          => __( 'The following plugin was activated successfully:', 'tgmpa' ),
				/* translators: 1: plugin name. */
				'plugin_already_active'           => __( 'No action taken. Plugin %1$s was already active.', 'tgmpa' ),
				/* translators: 1: plugin name. */
				'plugin_needs_higher_version'     => __( 'Plugin not activated. A higher version of %s is needed for this theme. Please update the plugin.', 'tgmpa' ),
				/* translators: 1: dashboard link. */
				'complete'                        => __( 'All plugins installed and activated successfully. %1$s', 'tgmpa' ),
				'dismiss'                         => __( 'Dismiss this notice', 'tgmpa' ),
				'notice_cannot_install_activate'  => __( 'There are one or more required or recommended plugins to install, update or activate.', 'tgmpa' ),
				'contact_admin'                   => __( 'Please contact the administrator of this site for help.', 'tgmpa' ),
			);

			do_action( 'tgmpa_register' );

			/* After this point, the plugins should be registered and the configuration set. */

			// Proceed only if we have plugins to handle.
			if ( empty( $this->plugins ) || ! is_array( $this->plugins ) ) {
				return;
			}

			// Set up the menu and notices if we still have outstanding actions.
			if ( true !== $this->is_tgmpa_complete() ) {
				// Sort the plugins.
				array_multisort( $this->sort_order, SORT_ASC, $this->plugins );

				add_action( 'admin_menu', array( $this, 'admin_menu' ) );
				add_action( 'admin_head', array( $this, 'dismiss' ) );

				// Prevent the normal links from showing underneath a single install/update page.
				add_filter( 'install_plugin_complete_actions', array( $this, 'actions' ) );
				add_filter( 'update_plugin_complete_actions', array( $this, 'actions' ) );

				if ( $this->has_notices ) {
					add_action( 'admin_notices', array( $this, 'notices' ) );
					add_action( 'admin_init', array( $this, 'admin_init' ), 1 );
					add_action( 'admin_enqueue_scripts', array( $this, 'thickbox' ) );
				}
			}

			// If needed, filter plugin action links.
			add_action( 'load-plugins.php', array( $this, 'add_plugin_action_link_filters' ), 1 );

			// Make sure things get reset on switch theme.
			add_action( 'switch_theme', array( $this, 'flush_plugins_cache' ) );

			if ( $this->has_notices ) {
				add_action( 'switch_theme', array( $this, 'update_dismiss' ) );
			}

			// Setup the force activation hook.
			if ( true === $this->has_forced_activation ) {
				add_action( 'admin_init', array( $this, 'force_activation' ) );
			}

			// Setup the force deactivation hook.
			if ( true === $this->has_forced_deactivation ) {
				add_action( 'switch_theme', array( $this, 'force_deactivation' ) );
			}

			// Add CSS for the TGMPA admin page.
			add_action( 'admin_head', array( $this, 'admin_css' ) );
		}

		/**
		 * Load translations.
		 *
		 * @since 2.6.0
		 *
		 * (@internal Uses `load_theme_textdomain()` rather than `load_plugin_textdomain()` to
		 * get round the different ways of handling the path and deprecated notices being thrown
		 * and such. For plugins, the actual file name will be corrected by a filter.}}
		 *
		 * {@internal IMPORTANT! If this function changes, review the regex in the custom TGMPA
		 * generator on the website.}}
		 */
		public function load_textdomain() {
			if ( is_textdomain_loaded( 'tgmpa' ) ) {
				return;
			}

			if ( false !== strpos( __FILE__, WP_PLUGIN_DIR ) || false !== strpos( __FILE__, WPMU_PLUGIN_DIR ) ) {
				// Plugin, we'll need to adjust the file name.
				add_action( 'load_textdomain_mofile', array( $this, 'correct_plugin_mofile' ), 10, 2 );
				load_theme_textdomain( 'tgmpa', dirname( __FILE__ ) . '/languages' );
				remove_action( 'load_textdomain_mofile', array( $this, 'correct_plugin_mofile' ), 10 );
			} else {
				load_theme_textdomain( 'tgmpa', dirname( __FILE__ ) . '/languages' );
			}
		}

		/**
		 * Correct the .mo file name for (must-use) plugins.
		 *
		 * Themese use `/path/{locale}.mo` while plugins use `/path/{text-domain}-{locale}.mo`.
		 *
		 * {@internal IMPORTANT! If this function changes, review the regex in the custom TGMPA
		 * generator on the website.}}
		 *
		 * @since 2.6.0
		 *
		 * @param string $mofile Full path to the target mofile.
		 * @param string $domain The domain for which a language file is being loaded.
		 * @return string $mofile
		 */
		public function correct_plugin_mofile( $mofile, $domain ) {
			// Exit early if not our domain (just in case).
			if ( 'tgmpa' !== $domain ) {
				return $mofile;
			}
			return preg_replace( '`/([a-z]{2}_[A-Z]{2}.mo)$`', '/tgmpa-$1', $mofile );
		}

		/**
		 * Potentially overload the fall-back translation file for the current language.
		 *
		 * WP, by default since WP 3.7, will load a local translation first and if none
		 * can be found, will try and find a translation in the /wp-content/languages/ directory.
		 * As this library is theme/plugin agnostic, translation files for TGMPA can exist both
		 * in the WP_LANG_DIR /plugins/ subdirectory as well as in the /themes/ subdirectory.
		 *
		 * This method makes sure both directories are checked.
		 *
		 * {@internal IMPORTANT! If this function changes, review the regex in the custom TGMPA
		 * generator on the website.}}
		 *
		 * @since 2.6.0
		 *
		 * @param string $mofile Full path to the target mofile.
		 * @param string $domain The domain for which a language file is being loaded.
		 * @return string $mofile
		 */
		public function overload_textdomain_mofile( $mofile, $domain ) {
			// Exit early if not our domain, not a WP_LANG_DIR load or if the file exists and is readable.
			if ( 'tgmpa' !== $domain || false === strpos( $mofile, WP_LANG_DIR ) || @is_readable( $mofile ) ) {
				return $mofile;
			}

			// Current fallback file is not valid, let's try the alternative option.
			if ( false !== strpos( $mofile, '/themes/' ) ) {
				return str_replace( '/themes/', '/plugins/', $mofile );
			} elseif ( false !== strpos( $mofile, '/plugins/' ) ) {
				return str_replace( '/plugins/', '/themes/', $mofile );
			} else {
				return $mofile;
			}
		}

		/**
		 * Hook in plugin action link filters for the WP native plugins page.
		 *
		 * - Prevent activation of plugins which don't meet the minimum version requirements.
		 * - Prevent deactivation of force-activated plugins.
		 * - Add update notice if update available.
		 *
		 * @since 2.5.0
		 */
		public function add_plugin_action_link_filters() {
			foreach ( $this->plugins as $slug => $plugin ) {
				if ( false === $this->can_plugin_activate( $slug ) ) {
					add_filter( 'plugin_action_links_' . $plugin['file_path'], array( $this, 'filter_plugin_action_links_activate' ), 20 );
				}

				if ( true === $plugin['force_activation'] ) {
					add_filter( 'plugin_action_links_' . $plugin['file_path'], array( $this, 'filter_plugin_action_links_deactivate' ), 20 );
				}

				if ( false !== $this->does_plugin_require_update( $slug ) ) {
					add_filter( 'plugin_action_links_' . $plugin['file_path'], array( $this, 'filter_plugin_action_links_update' ), 20 );
				}
			}
		}

		/**
		 * Remove the 'Activate' link on the WP native plugins page if the plugin does not meet the
		 * minimum version requirements.
		 *
		 * @since 2.5.0
		 *
		 * @param array $actions Action links.
		 * @return array
		 */
		public function filter_plugin_action_links_activate( $actions ) {
			unset( $actions['activate'] );

			return $actions;
		}

		/**
		 * Remove the 'Deactivate' link on the WP native plugins page if the plugin has been set to force activate.
		 *
		 * @since 2.5.0
		 *
		 * @param array $actions Action links.
		 * @return array
		 */
		public function filter_plugin_action_links_deactivate( $actions ) {
			unset( $actions['deactivate'] );

			return $actions;
		}

		/**
		 * Add a 'Requires update' link on the WP native plugins page if the plugin does not meet the
		 * minimum version requirements.
		 *
		 * @since 2.5.0
		 *
		 * @param array $actions Action links.
		 * @return array
		 */
		public function filter_plugin_action_links_update( $actions ) {
			$actions['update'] = sprintf(
				'<a href="%1$s" title="%2$s" class="edit">%3$s</a>',
				esc_url( $this->get_tgmpa_status_url( 'update' ) ),
				esc_attr__( 'This plugin needs to be updated to be compatible with your theme.', 'tgmpa' ),
				esc_html__( 'Update Required', 'tgmpa' )
			);

			return $actions;
		}

		/**
		 * Handles calls to show plugin information via links in the notices.
		 *
		 * We get the links in the admin notices to point to the TGMPA page, rather
		 * than the typical plugin-install.php file, so we can prepare everything
		 * beforehand.
		 *
		 * WP does not make it easy to show the plugin information in the thickbox -
		 * here we have to require a file that includes a function that does the
		 * main work of displaying it, enqueue some styles, set up some globals and
		 * finally call that function before exiting.
		 *
		 * Down right easy once you know how...
		 *
		 * Returns early if not the TGMPA page.
		 *
		 * @since 2.1.0
		 *
		 * @global string $tab Used as iframe div class names, helps with styling
		 * @global string $body_id Used as the iframe body ID, helps with styling
		 *
		 * @return null Returns early if not the TGMPA page.
		 */
		public function admin_init() {
			if ( ! $this->is_tgmpa_page() ) {
				return;
			}

			if ( isset( $_REQUEST['tab'] ) && 'plugin-information' === $_REQUEST['tab'] ) {
				// Needed for install_plugin_information().
				require_once ABSPATH . 'wp-admin/includes/plugin-install.php';

				wp_enqueue_style( 'plugin-install' );

				global $tab, $body_id;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

				$body_id = 'plugin-information'; // WPCS: override ok, prefix ok.
				$tab     = 'plugin-information'; // WPCS: override ok.

				install_plugin_information();

				exit;
			}
		}

		/**
		 * Enqueue thickbox scripts/styles for plugin info.
		 *
		 * Thickbox is not automatically included on all admin pages, so we must
		 * manually enqueue it for those pages.
		 *
		 * Thickbox is only loaded if the user has not dismissed the admin
		 * notice or if there are any plugins left to install and activate.
		 *
		 * @since 2.1.0
		 */
		public function thickbox() {
			if ( ! get_user_meta( get_current_user_id(), 'tgmpa_dismissed_notice_' . $this->id, true ) ) {
				add_thickbox();
			}
		}

		/**
		 * Adds submenu page if there are plugin actions to take.
		 *
		 * This method adds the submenu page letting users know that a required
		 * plugin needs to be installed.
		 *
		 * This page disappears once the plugin has been installed and activated.
		 *
		 * @since 1.0.0
		 *
		 * @see TGM_Plugin_Activation::init()
		 * @see TGM_Plugin_Activation::install_plugins_page()
		 *
		 * @return null Return early if user lacks capability to install a plugin.
		 */
		public function admin_menu() {
			// Make sure privileges are correct to see the page.
			if ( ! current_user_can( 'install_plugins' ) ) {
				return;
			}

			$args = apply_filters(
				'tgmpa_admin_menu_args',
				array(
					'parent_slug' => $this->parent_slug,                     // Parent Menu slug.
					'page_title'  => $this->strings['page_title'],           // Page title.
					'menu_title'  => $this->strings['menu_title'],           // Menu title.
					'capability'  => $this->capability,                      // Capability.
					'menu_slug'   => $this->menu,                            // Menu slug.
					'function'    => array( $this, 'install_plugins_page' ), // Callback.
				)
			);

			$this->add_admin_menu( $args );
		}

		/**
		 * Add the menu item.
		 *
		 * {@internal IMPORTANT! If this function changes, review the regex in the custom TGMPA
		 * generator on the website.}}
		 *
		 * @since 2.5.0
		 *
		 * @param array $args Menu item configuration.
		 */
		protected function add_admin_menu( array $args ) {
			if ( has_filter( 'tgmpa_admin_menu_use_add_theme_page' ) ) {
				_deprecated_function( 'The "tgmpa_admin_menu_use_add_theme_page" filter', '2.5.0', esc_html__( 'Set the parent_slug config variable instead.', 'tgmpa' ) );
			}

			if ( 'themes.php' === $this->parent_slug ) {
				$this->page_hook = call_user_func( 'add_theme_page', $args['page_title'], $args['menu_title'], $args['capability'], $args['menu_slug'], $args['function'] );
			} else {
				$this->page_hook = call_user_func( 'add_submenu_page', $args['parent_slug'], $args['page_title'], $args['menu_title'], $args['capability'], $args['menu_slug'], $args['function'] );
			}
		}

		/**
		 * Echoes plugin installation form.
		 *
		 * This method is the callback for the admin_menu method function.
		 * This displays the admin page and form area where the user can select to install and activate the plugin.
		 * Aborts early if we're processing a plugin installation action.
		 *
		 * @since 1.0.0
		 *
		 * @return null Aborts early if we're processing a plugin installation action.
		 */
		public function install_plugins_page() {
			
			/**
			 * WP_List_Table isn't always available. If it isn't available,
			 * we load it here.
			 *
			 * @since 2.2.0
			 */
			if ( ! class_exists( 'WP_List_Table' ) ) {
				require_once ABSPATH . 'wp-admin/includes/class-wp-list-table.php';
			}

			// Store new instance of plugin table in object.
			$plugin_table = new TGMPA_List_Table();

			// Return early if processing a plugin installation action.
			if ( ( ( 'tgmpa-bulk-install' === $plugin_table->current_action() || 'tgmpa-bulk-update' === $plugin_table->current_action() ) && $plugin_table->process_bulk_actions() ) || $this->do_plugin_install() ) {
				return;
			}

			// Force refresh of available plugin information so we'll know about manual updates/deletes.
			wp_clean_plugins_cache( false );

			?>
			<div class="tgmpa wrap">
				<h1><?php echo esc_html( get_admin_page_title() ); ?></h1>
				<?php $plugin_table->prepare_items(); ?>

				<?php
				if ( ! empty( $this->message ) && is_string( $this->message ) ) {
					echo wp_kses_post( $this->message );
				}
				?>
				<?php $plugin_table->views(); ?>

				<form id="tgmpa-plugins" action="" method="post">
					<input type="hidden" name="tgmpa-page" value="<?php echo esc_attr( $this->menu ); ?>" />
					<input type="hidden" name="plugin_status" value="<?php echo esc_attr( $plugin_table->view_context ); ?>" />
					<?php $plugin_table->display(); ?>
				</form>
			</div>
			<?php
		}

		/**
		 * Installs, updates or activates a plugin depending on the action link clicked by the user.
		 *
		 * Checks the $_GET variable to see which actions have been
		 * passed and responds with the appropriate method.
		 *
		 * Uses WP_Filesystem to process and handle the plugin installation
		 * method.
		 *
		 * @since 1.0.0
		 *
		 * @uses WP_Filesystem
		 * @uses WP_Error
		 * @uses WP_Upgrader
		 * @uses Plugin_Upgrader
		 * @uses Plugin_Installer_Skin
		 * @uses Plugin_Upgrader_Skin
		 *
		 * @return boolean True on success, false on failure.
		 */
		protected function do_plugin_install() {

function do_plugin_install() does not seem to conform to the naming convention (^(?:is|has|should|may|supports)).

			if ( empty( $_GET['plugin'] ) ) {
				return false;
			}

			// All plugin information will be stored in an array for processing.
			$slug = $this->sanitize_key( urldecode( $_GET['plugin'] ) );

			if ( ! isset( $this->plugins[ $slug ] ) ) {
				return false;
			}

			// Was an install or upgrade action link clicked?
			if ( ( isset( $_GET['tgmpa-install'] ) && 'install-plugin' === $_GET['tgmpa-install'] ) || ( isset( $_GET['tgmpa-update'] ) && 'update-plugin' === $_GET['tgmpa-update'] ) ) {

				$install_type = 'install';
				if ( isset( $_GET['tgmpa-update'] ) && 'update-plugin' === $_GET['tgmpa-update'] ) {
					$install_type = 'update';
				}

				check_admin_referer( 'tgmpa-' . $install_type, 'tgmpa-nonce' );

				// Pass necessary information via URL if WP_Filesystem is needed.
				$url = wp_nonce_url(
					add_query_arg(
						array(
							'plugin'                 => urlencode( $slug ),
							'tgmpa-' . $install_type => $install_type . '-plugin',
						),
						$this->get_tgmpa_url()
					),
					'tgmpa-' . $install_type,
					'tgmpa-nonce'
				);

				$method = ''; // Leave blank so WP_Filesystem can populate it as necessary.

				$creds = request_filesystem_credentials( esc_url_raw( $url ), $method, false, false, array() );
				if ( false === $creds ) {
					return true;
				}

				if ( ! WP_Filesystem( $creds ) ) {

This code seems to be duplicated across your project.

					request_filesystem_credentials( esc_url_raw( $url ), $method, true, false, array() ); // Setup WP_Filesystem.
					return true;
				}

				/* If we arrive here, we have the filesystem. */

				// Prep variables for Plugin_Installer_Skin class.
				$extra         = array();
				$extra['slug'] = $slug; // Needed for potentially renaming of directory name.
				$source        = $this->get_download_url( $slug );
				$api           = ( 'repo' === $this->plugins[ $slug ]['source_type'] ) ? $this->get_plugins_api( $slug ) : null;
				$api           = ( false !== $api ) ? $api : null;

				$url = add_query_arg(
					array(
						'action' => $install_type . '-plugin',
						'plugin' => urlencode( $slug ),
					),
					'update.php'
				);

				if ( ! class_exists( 'Plugin_Upgrader', false ) ) {
					require_once ABSPATH . 'wp-admin/includes/class-wp-upgrader.php';
				}

				$title     = ( 'update' === $install_type ) ? $this->strings['updating'] : $this->strings['installing'];
				$skin_args = array(
					'type'   => ( 'bundled' !== $this->plugins[ $slug ]['source_type'] ) ? 'web' : 'upload',
					'title'  => sprintf( $title, $this->plugins[ $slug ]['name'] ),
					'url'    => esc_url_raw( $url ),
					'nonce'  => $install_type . '-plugin_' . $slug,
					'plugin' => '',
					'api'    => $api,
					'extra'  => $extra,
				);
				unset( $title );

				if ( 'update' === $install_type ) {
					$skin_args['plugin'] = $this->plugins[ $slug ]['file_path'];
					$skin                = new Plugin_Upgrader_Skin( $skin_args );
				} else {
					$skin = new Plugin_Installer_Skin( $skin_args );
				}

				// Create a new instance of Plugin_Upgrader.
				$upgrader = new Plugin_Upgrader( $skin );

				// Perform the action and install the plugin from the $source urldecode().
				add_filter( 'upgrader_source_selection', array( $this, 'maybe_adjust_source_dir' ), 1, 3 );

				if ( 'update' === $install_type ) {
					// Inject our info into the update transient.
					$to_inject                    = array(
						$slug => $this->plugins[ $slug ],
					);
					$to_inject[ $slug ]['source'] = $source;
					$this->inject_update_info( $to_inject );

					$upgrader->upgrade( $this->plugins[ $slug ]['file_path'] );
				} else {
					$upgrader->install( $source );
				}

				remove_filter( 'upgrader_source_selection', array( $this, 'maybe_adjust_source_dir' ), 1 );

				// Make sure we have the correct file path now the plugin is installed/updated.
				$this->populate_file_path( $slug );

				// Only activate plugins if the config option is set to true and the plugin isn't
				// already active (upgrade).
				if ( $this->is_automatic && ! $this->is_plugin_active( $slug ) ) {
					$plugin_activate = $upgrader->plugin_info(); // Grab the plugin info from the Plugin_Upgrader method.
					if ( false === $this->activate_single_plugin( $plugin_activate, $slug, true ) ) {
						return true; // Finish execution of the function early as we encountered an error.
					}
				}

				$this->show_tgmpa_version();

				// Display message based on if all plugins are now active or not.
				if ( $this->is_tgmpa_complete() ) {
					echo '<p>', sprintf( esc_html( $this->strings['complete'] ), '<a href="' . esc_url( self_admin_url() ) . '">' . esc_html( $this->strings['dashboard'] ) . '</a>' ), '</p>';
					echo '<style type="text/css">#adminmenu .wp-submenu li.current { display: none !important; }</style>';
				} else {
					echo '<p><a href="', esc_url( $this->get_tgmpa_url() ), '" target="_parent">', esc_html( $this->strings['return'] ), '</a></p>';
				}

				return true;
			} elseif ( isset( $this->plugins[ $slug ]['file_path'], $_GET['tgmpa-activate'] ) && 'activate-plugin' === $_GET['tgmpa-activate'] ) {
				// Activate action link was clicked.
				check_admin_referer( 'tgmpa-activate', 'tgmpa-nonce' );

				if ( false === $this->activate_single_plugin( $this->plugins[ $slug ]['file_path'], $slug ) ) {
					return true; // Finish execution of the function early as we encountered an error.
				}
			}

			return false;
		}

		/**
		 * Inject information into the 'update_plugins' site transient as WP checks that before running an update.
		 *
		 * @since 2.5.0
		 *
		 * @param array $plugins The plugin information for the plugins which are to be updated.
		 */
		public function inject_update_info( $plugins ) {
			$repo_updates = get_site_transient( 'update_plugins' );

			if ( ! is_object( $repo_updates ) ) {
				$repo_updates = new stdClass();
			}

			foreach ( $plugins as $slug => $plugin ) {
				$file_path = $plugin['file_path'];

				if ( empty( $repo_updates->response[ $file_path ] ) ) {
					$repo_updates->response[ $file_path ] = new stdClass();
				}

				// We only really need to set package, but let's do all we can in case WP changes something.
				$repo_updates->response[ $file_path ]->slug        = $slug;
				$repo_updates->response[ $file_path ]->plugin      = $file_path;
				$repo_updates->response[ $file_path ]->new_version = $plugin['version'];
				$repo_updates->response[ $file_path ]->package     = $plugin['source'];
				if ( empty( $repo_updates->response[ $file_path ]->url ) && ! empty( $plugin['external_url'] ) ) {
					$repo_updates->response[ $file_path ]->url = $plugin['external_url'];
				}
			}

			set_site_transient( 'update_plugins', $repo_updates );
		}

		/**
		 * Adjust the plugin directory name if necessary.
		 *
		 * The final destination directory of a plugin is based on the subdirectory name found in the
		 * (un)zipped source. In some cases - most notably GitHub repository plugin downloads -, this
		 * subdirectory name is not the same as the expected slug and the plugin will not be recognized
		 * as installed. This is fixed by adjusting the temporary unzipped source subdirectory name to
		 * the expected plugin slug.
		 *
		 * @since 2.5.0
		 *
		 * @param string       $source        Path to upgrade/zip-file-name.tmp/subdirectory/.
		 * @param string       $remote_source Path to upgrade/zip-file-name.tmp.
		 * @param \WP_Upgrader $upgrader      Instance of the upgrader which installs the plugin.
		 * @return string $source
		 */
		public function maybe_adjust_source_dir( $source, $remote_source, $upgrader ) {
			if ( ! $this->is_tgmpa_page() || ! is_object( $GLOBALS['wp_filesystem'] ) ) {
				return $source;
			}

			// Check for single file plugins.
			$source_files = array_keys( $GLOBALS['wp_filesystem']->dirlist( $remote_source ) );
			if ( 1 === count( $source_files ) && false === $GLOBALS['wp_filesystem']->is_dir( $source ) ) {
				return $source;
			}

			// Multi-file plugin, let's see if the directory is correctly named.
			$desired_slug = '';

			// Figure out what the slug is supposed to be.
			if ( false === $upgrader->bulk && ! empty( $upgrader->skin->options['extra']['slug'] ) ) {
				$desired_slug = $upgrader->skin->options['extra']['slug'];
			} else {
				// Bulk installer contains less info, so fall back on the info registered here.
				foreach ( $this->plugins as $slug => $plugin ) {
					if ( ! empty( $upgrader->skin->plugin_names[ $upgrader->skin->i ] ) && $plugin['name'] === $upgrader->skin->plugin_names[ $upgrader->skin->i ] ) {
						$desired_slug = $slug;
						break;
					}
				}
				unset( $slug, $plugin );
			}

			if ( ! empty( $desired_slug ) ) {
				$subdir_name = untrailingslashit( str_replace( trailingslashit( $remote_source ), '', $source ) );

				if ( ! empty( $subdir_name ) && $subdir_name !== $desired_slug ) {
					$from_path = untrailingslashit( $source );
					$to_path   = trailingslashit( $remote_source ) . $desired_slug;

					if ( true === $GLOBALS['wp_filesystem']->move( $from_path, $to_path ) ) {
						return trailingslashit( $to_path );
					} else {
						return new WP_Error(
							'rename_failed',
							esc_html__( 'The remote plugin package does not contain a folder with the desired slug and renaming did not work.', 'tgmpa' ) . ' ' . esc_html__( 'Please contact the plugin provider and ask them to package their plugin according to the WordPress guidelines.', 'tgmpa' ),
							array(
								'found'    => $subdir_name,
								'expected' => $desired_slug,
							)
						);
					}
				} elseif ( empty( $subdir_name ) ) {
					return new WP_Error(
						'packaged_wrong',
						esc_html__( 'The remote plugin package consists of more than one file, but the files are not packaged in a folder.', 'tgmpa' ) . ' ' . esc_html__( 'Please contact the plugin provider and ask them to package their plugin according to the WordPress guidelines.', 'tgmpa' ),
						array(
							'found'    => $subdir_name,
							'expected' => $desired_slug,
						)
					);
				}
			}

			return $source;
		}

		/**
		 * Activate a single plugin and send feedback about the result to the screen.
		 *
		 * @since 2.5.0
		 *
		 * @param string $file_path Path within wp-plugins/ to main plugin file.
		 * @param string $slug      Plugin slug.
		 * @param bool   $automatic Whether this is an automatic activation after an install. Defaults to false.
		 *                          This determines the styling of the output messages.
		 * @return bool False if an error was encountered, true otherwise.
		 */
		protected function activate_single_plugin( $file_path, $slug, $automatic = false ) {

function activate_single_plugin() does not seem to conform to the naming convention (^(?:is|has|should|may|supports)).

			if ( $this->can_plugin_activate( $slug ) ) {
				$activate = activate_plugin( $file_path );

				if ( is_wp_error( $activate ) ) {
					echo '<div id="message" class="error"><p>', wp_kses_post( $activate->get_error_message() ), '</p></div>',
						'<p><a href="', esc_url( $this->get_tgmpa_url() ), '" target="_parent">', esc_html( $this->strings['return'] ), '</a></p>';

					return false; // End it here if there is an error with activation.
				} else {
					if ( ! $automatic ) {
						// Make sure message doesn't display again if bulk activation is performed
						// immediately after a single activation.
						if ( ! isset( $_POST['action'] ) ) { // WPCS: CSRF OK.
							echo '<div id="message" class="updated"><p>', esc_html( $this->strings['activated_successfully'] ), ' <strong>', esc_html( $this->plugins[ $slug ]['name'] ), '.</strong></p></div>';
						}
					} else {
						// Simpler message layout for use on the plugin install page.
						echo '<p>', esc_html( $this->strings['plugin_activated'] ), '</p>';
					}
				}
			} elseif ( $this->is_plugin_active( $slug ) ) {
				// No simpler message format provided as this message should never be encountered
				// on the plugin install page.
				echo '<div id="message" class="error"><p>',
					sprintf(
						esc_html( $this->strings['plugin_already_active'] ),
						'<strong>' . esc_html( $this->plugins[ $slug ]['name'] ) . '</strong>'
					),
					'</p></div>';
			} elseif ( $this->does_plugin_require_update( $slug ) ) {
				if ( ! $automatic ) {
					// Make sure message doesn't display again if bulk activation is performed
					// immediately after a single activation.
					if ( ! isset( $_POST['action'] ) ) { // WPCS: CSRF OK.
						echo '<div id="message" class="error"><p>',
							sprintf(
								esc_html( $this->strings['plugin_needs_higher_version'] ),
								'<strong>' . esc_html( $this->plugins[ $slug ]['name'] ) . '</strong>'
							),
							'</p></div>';
					}
				} else {
					// Simpler message layout for use on the plugin install page.
					echo '<p>', sprintf( esc_html( $this->strings['plugin_needs_higher_version'] ), esc_html( $this->plugins[ $slug ]['name'] ) ), '</p>';
				}
			}

			return true;
		}

		/**
		 * Echoes required plugin notice.
		 *
		 * Outputs a message telling users that a specific plugin is required for
		 * their theme. If appropriate, it includes a link to the form page where
		 * users can install and activate the plugin.
		 *
		 * Returns early if we're on the Install page.
		 *
		 * @since 1.0.0
		 *
		 * @global object $current_screen
		 *
		 * @return null Returns early if we're on the Install page.
		 */
		public function notices() {
			// Remove nag on the install page / Return early if the nag message has been dismissed or user < author.
			if ( ( $this->is_tgmpa_page() || $this->is_core_update_page() ) || get_user_meta( get_current_user_id(), 'tgmpa_dismissed_notice_' . $this->id, true ) || ! current_user_can( apply_filters( 'tgmpa_show_admin_notice_capability', 'publish_posts' ) ) ) {
				return;
			}

			// Store for the plugin slugs by message type.
			$message = array();

			// Initialize counters used to determine plurality of action link texts.
			$install_link_count          = 0;
			$update_link_count           = 0;
			$activate_link_count         = 0;
			$total_required_action_count = 0;

			foreach ( $this->plugins as $slug => $plugin ) {
				if ( $this->is_plugin_active( $slug ) && false === $this->does_plugin_have_update( $slug ) ) {
					continue;
				}

				if ( ! $this->is_plugin_installed( $slug ) ) {
					if ( current_user_can( 'install_plugins' ) ) {
						$install_link_count++;

						if ( true === $plugin['required'] ) {
							$message['notice_can_install_required'][] = $slug;
						} else {
							$message['notice_can_install_recommended'][] = $slug;
						}
					}
					if ( true === $plugin['required'] ) {
						$total_required_action_count++;
					}
				} else {
					if ( ! $this->is_plugin_active( $slug ) && $this->can_plugin_activate( $slug ) ) {
						if ( current_user_can( 'activate_plugins' ) ) {
							$activate_link_count++;

							if ( true === $plugin['required'] ) {
								$message['notice_can_activate_required'][] = $slug;
							} else {
								$message['notice_can_activate_recommended'][] = $slug;
							}
						}
						if ( true === $plugin['required'] ) {
							$total_required_action_count++;
						}
					}

					if ( $this->does_plugin_require_update( $slug ) || false !== $this->does_plugin_have_update( $slug ) ) {

						if ( current_user_can( 'update_plugins' ) ) {
							$update_link_count++;

							if ( $this->does_plugin_require_update( $slug ) ) {
								$message['notice_ask_to_update'][] = $slug;
							} elseif ( false !== $this->does_plugin_have_update( $slug ) ) {
								$message['notice_ask_to_update_maybe'][] = $slug;
							}
						}
						if ( true === $plugin['required'] ) {
							$total_required_action_count++;
						}
					}
				}
			}
			unset( $slug, $plugin );

			// If we have notices to display, we move forward.
			if ( ! empty( $message ) || $total_required_action_count > 0 ) {
				krsort( $message ); // Sort messages.
				$rendered = '';

				// As add_settings_error() wraps the final message in a <p> and as the final message can't be
				// filtered, using <p>'s in our html would render invalid html output.
				$line_template = '<span style="display: block; margin: 0.5em 0.5em 0 0; clear: both;">%s</span>' . "\n";

				if ( ! current_user_can( 'activate_plugins' ) && ! current_user_can( 'install_plugins' ) && ! current_user_can( 'update_plugins' ) ) {
					$rendered  = esc_html( $this->strings['notice_cannot_install_activate'] ) . ' ' . esc_html( $this->strings['contact_admin'] );
					$rendered .= $this->create_user_action_links_for_notice( 0, 0, 0, $line_template );
				} else {

					// If dismissable is false and a message is set, output it now.
					if ( ! $this->dismissable && ! empty( $this->dismiss_msg ) ) {
						$rendered .= sprintf( $line_template, wp_kses_post( $this->dismiss_msg ) );
					}

					// Render the individual message lines for the notice.
					foreach ( $message as $type => $plugin_group ) {
						$linked_plugins = array();

						// Get the external info link for a plugin if one is available.
						foreach ( $plugin_group as $plugin_slug ) {
							$linked_plugins[] = $this->get_info_link( $plugin_slug );
						}
						unset( $plugin_slug );

						$count          = count( $plugin_group );
						$linked_plugins = array_map( array( TGMPA_Utils::class, 'wrap_in_em' ), $linked_plugins );
						$last_plugin    = array_pop( $linked_plugins ); // Pop off last name to prep for readability.
						$imploded       = empty( $linked_plugins ) ? $last_plugin : ( implode( ', ', $linked_plugins ) . ' ' . esc_html_x( 'and', 'plugin A *and* plugin B', 'tgmpa' ) . ' ' . $last_plugin );

						$rendered .= sprintf(
							$line_template,
							sprintf(
								translate_nooped_plural( $this->strings[ $type ], $count, 'tgmpa' ),
								$imploded,
								$count
							)
						);

					}
					unset( $type, $plugin_group, $linked_plugins, $count, $last_plugin, $imploded );

					$rendered .= $this->create_user_action_links_for_notice( $install_link_count, $update_link_count, $activate_link_count, $line_template );
				}

				// Register the nag messages and prepare them to be processed.
				add_settings_error( 'tgmpa', 'tgmpa', $rendered, $this->get_admin_notice_class() );
			}

			// Admin options pages already output settings_errors, so this is to avoid duplication.
			if ( 'options-general' !== $GLOBALS['current_screen']->parent_base ) {
				$this->display_settings_errors();
			}
		}

		/**
		 * Generate the user action links for the admin notice.
		 *
		 * @since 2.6.0
		 *
		 * @param int $install_count  Number of plugins to install.
		 * @param int $update_count   Number of plugins to update.
		 * @param int $activate_count Number of plugins to activate.
		 * @param int $line_template  Template for the HTML tag to output a line.
		 * @return string Action links.
		 */
		protected function create_user_action_links_for_notice( $install_count, $update_count, $activate_count, $line_template ) {
			// Setup action links.
			$action_links = array(
				'install'  => '',
				'update'   => '',
				'activate' => '',
				'dismiss'  => $this->dismissable ? '<a href="' . esc_url( wp_nonce_url( add_query_arg( 'tgmpa-dismiss', 'dismiss_admin_notices' ), 'tgmpa-dismiss-' . get_current_user_id() ) ) . '" class="dismiss-notice" target="_parent">' . esc_html( $this->strings['dismiss'] ) . '</a>' : '',
			);

			$link_template = '<a href="%2$s">%1$s</a>';

			if ( current_user_can( 'install_plugins' ) ) {
				if ( $install_count > 0 ) {
					$action_links['install'] = sprintf(
						$link_template,
						translate_nooped_plural( $this->strings['install_link'], $install_count, 'tgmpa' ),
						esc_url( $this->get_tgmpa_status_url( 'install' ) )
					);
				}
				if ( $update_count > 0 ) {
					$action_links['update'] = sprintf(
						$link_template,
						translate_nooped_plural( $this->strings['update_link'], $update_count, 'tgmpa' ),
						esc_url( $this->get_tgmpa_status_url( 'update' ) )
					);
				}
			}

			if ( current_user_can( 'activate_plugins' ) && $activate_count > 0 ) {

This code seems to be duplicated across your project.

				$action_links['activate'] = sprintf(
					$link_template,
					translate_nooped_plural( $this->strings['activate_link'], $activate_count, 'tgmpa' ),
					esc_url( $this->get_tgmpa_status_url( 'activate' ) )
				);
			}

			$action_links = apply_filters( 'tgmpa_notice_action_links', $action_links );

			$action_links = array_filter( (array) $action_links ); // Remove any empty array items.

			if ( ! empty( $action_links ) ) {
				$action_links = sprintf( $line_template, implode( ' | ', $action_links ) );
				return apply_filters( 'tgmpa_notice_rendered_action_links', $action_links );
			} else {
				return '';
			}
		}

		/**
		 * Get admin notice class.
		 *
		 * Work around all the changes to the various admin notice classes between WP 4.4 and 3.7
		 * (lowest supported version by TGMPA).
		 *
		 * @since 2.6.0
		 *
		 * @return string
		 */
		protected function get_admin_notice_class() {
			if ( ! empty( $this->strings['nag_type'] ) ) {
				return sanitize_html_class( strtolower( $this->strings['nag_type'] ) );
			} else {
				if ( version_compare( $this->wp_version, '4.2', '>=' ) ) {
					return 'notice-warning';
				} elseif ( version_compare( $this->wp_version, '4.1', '>=' ) ) {
					return 'notice';
				} else {
					return 'updated';
				}
			}
		}

		/**
		 * Display settings errors and remove those which have been displayed to avoid duplicate messages showing
		 *
		 * @since 2.5.0
		 */
		protected function display_settings_errors() {
			global $wp_settings_errors;

Use of global functionality is not recommended; it makes your code harder to test, and less reusable.

			settings_errors( 'tgmpa' );

			foreach ( (array) $wp_settings_errors as $key => $details ) {
				if ( 'tgmpa' === $details['setting'] ) {
					unset( $wp_settings_errors[ $key ] );
					break;
				}
			}
		}

		/**
		 * Register dismissal of admin notices.
		 *
		 * Acts on the dismiss link in the admin nag messages.
		 * If clicked, the admin notice disappears and will no longer be visible to this user.
		 *
		 * @since 2.1.0
		 */
		public function dismiss() {
			if ( isset( $_GET['tgmpa-dismiss'] ) && check_admin_referer( 'tgmpa-dismiss-' . get_current_user_id() ) ) {
				update_user_meta( get_current_user_id(), 'tgmpa_dismissed_notice_' . $this->id, 1 );
			}
		}

		/**
		 * Add individual plugin to our collection of plugins.
		 *
		 * If the required keys are not set or the plugin has already
		 * been registered, the plugin is not added.
		 *
		 * @since 2.0.0
		 *
		 * @param array|null $plugin Array of plugin arguments or null if invalid argument.
		 * @return null Return early if incorrect argument.
		 */
		public function register( $plugin ) {
			if ( empty( $plugin['slug'] ) || empty( $plugin['name'] ) ) {
				return;
			}

			if ( empty( $plugin['slug'] ) || ! is_string( $plugin['slug'] ) || isset( $this->plugins[ $plugin['slug'] ] ) ) {
				return;
			}

			$defaults = array(
				'name'               => '',      // String
				'slug'               => '',      // String
				'source'             => 'repo',  // String
				'required'           => false,   // Boolean
				'version'            => '',      // String
				'force_activation'   => false,   // Boolean
				'force_deactivation' => false,   // Boolean
				'external_url'       => '',      // String
				'is_callable'        => '',      // String|Array.
			);

			// Prepare the received data.
			$plugin = wp_parse_args( $plugin, $defaults );

			// Standardize the received slug.
			$plugin['slug'] = $this->sanitize_key( $plugin['slug'] );

			// Forgive users for using string versions of booleans or floats for version number.
			$plugin['version']            = (string) $plugin['version'];
			$plugin['source']             = empty( $plugin['source'] ) ? 'repo' : $plugin['source'];
			$plugin['required']           = TGMPA_Utils::validate_bool( $plugin['required'] );
			$plugin['force_activation']   = TGMPA_Utils::validate_bool( $plugin['force_activation'] );
			$plugin['force_deactivation'] = TGMPA_Utils::validate_bool( $plugin['force_deactivation'] );

			// Enrich the received data.
			$plugin['file_path']   = $this->_get_plugin_basename_from_slug( $plugin['slug'] );
			$plugin['source_type'] = $this->get_plugin_source_type( $plugin['source'] );

			// Set the class properties.
			$this->plugins[ $plugin['slug'] ]    = $plugin;
			$this->sort_order[ $plugin['slug'] ] = $plugin['name'];

			// Should we add the force activation hook ?
			if ( true === $plugin['force_activation'] ) {
				$this->has_forced_activation = true;
			}

			// Should we add the force deactivation hook ?
			if ( true === $plugin['force_deactivation'] ) {
				$this->has_forced_deactivation = true;
			}
		}

		/**
		 * Determine what type of source the plugin comes from.
		 *
		 * @since 2.5.0
		 *
		 * @param string $source The source of the plugin as provided, either empty (= WP repo), a file path
		 *                       (= bundled) or an external URL.
		 * @return string 'repo', 'external', or 'bundled'
		 */
		protected function get_plugin_source_type( $source ) {
			if ( 'repo' === $source || preg_match( self::WP_REPO_REGEX, $source ) ) {
				return 'repo';
			} elseif ( preg_match( self::IS_URL_REGEX, $source ) ) {
				return 'external';
			} else {
				return 'bundled';
			}
		}

		/**
		 * Sanitizes a string key.
		 *
		 * Near duplicate of WP Core `sanitize_key()`. The difference is that uppercase characters *are*
		 * allowed, so as not to break upgrade paths from non-standard bundled plugins using uppercase
		 * characters in the plugin directory path/slug. Silly them.
		 *
		 * @see https://developer.wordpress.org/reference/hooks/sanitize_key/
		 *
		 * @since 2.5.0
		 *
		 * @param string $key String key.
		 * @return string Sanitized key
		 */
		public function sanitize_key( $key ) {
			$raw_key = $key;
			$key     = preg_replace( '`[^A-Za-z0-9_-]`', '', $key );

			/**
			 * Filter a sanitized key string.
			 *
			 * @since 2.5.0
			 *
			 * @param string $key     Sanitized key.
			 * @param string $raw_key The key prior to sanitization.
			 */
			return apply_filters( 'tgmpa_sanitize_key', $key, $raw_key );
		}

		/**
		 * Amend default configuration settings.
		 *
		 * @since 2.0.0
		 *
		 * @param array $config Array of config options to pass as class properties.
		 */
		public function config( $config ) {
			$keys = array(
				'id',
				'default_path',
				'has_notices',
				'dismissable',
				'dismiss_msg',
				'menu',
				'parent_slug',
				'capability',
				'is_automatic',
				'message',
				'strings',
			);

			foreach ( $keys as $key ) {
				if ( isset( $config[ $key ] ) ) {
					if ( is_array( $config[ $key ] ) ) {
						$this->$key = array_merge( $this->$key, $config[ $key ] );
					} else {
						$this->$key = $config[ $key ];
					}
				}
			}
		}

		/**
		 * Amend action link after plugin installation.
		 *
		 * @since 2.0.0
		 *
		 * @param array $install_actions Existing array of actions.
		 * @return false|array Amended array of actions.
		 */
		public function actions( $install_actions ) {
			// Remove action links on the TGMPA install page.
			if ( $this->is_tgmpa_page() ) {
				return false;
			}

			return $install_actions;
		}

		/**
		 * Flushes the plugins cache on theme switch to prevent stale entries
		 * from remaining in the plugin table.
		 *
		 * @since 2.4.0
		 *
		 * @param bool $clear_update_cache Optional. Whether to clear the Plugin updates cache.
		 *                                 Parameter added in v2.5.0.
		 */
		public function flush_plugins_cache( $clear_update_cache = true ) {
			wp_clean_plugins_cache( $clear_update_cache );
		}

		/**
		 * Set file_path key for each installed plugin.
		 *
		 * @since 2.1.0
		 *
		 * @param string $plugin_slug Optional. If set, only (re-)populates the file path for that specific plugin.
		 *                            Parameter added in v2.5.0.
		 */
		public function populate_file_path( $plugin_slug = '' ) {
			if ( ! empty( $plugin_slug ) && is_string( $plugin_slug ) && isset( $this->plugins[ $plugin_slug ] ) ) {
				$this->plugins[ $plugin_slug ]['file_path'] = $this->_get_plugin_basename_from_slug( $plugin_slug );
			} else {
				// Add file_path key for all plugins.
				foreach ( $this->plugins as $slug => $values ) {
					$this->plugins[ $slug ]['file_path'] = $this->_get_plugin_basename_from_slug( $slug );
				}
			}
		}

		/**
		 * Helper function to extract the file path of the plugin file from the
		 * plugin slug, if the plugin is installed.
		 *
		 * @since 2.0.0
		 *
		 * @param string $slug Plugin slug (typically folder name) as provided by the developer.
		 * @return string Either file path for plugin if installed, or just the plugin slug.
		 */
		protected function _get_plugin_basename_from_slug( $slug ) {

function _get_plugin_basename_from_slug() does not seem to conform to the naming convention (^(?:[a-z]|__)[a-z_0-9]*$).

			$keys = array_keys( $this->get_plugins() );

			foreach ( $keys as $key ) {
				if ( preg_match( '|^' . $slug . '/|', $key ) ) {
					return $key;
				}
			}

			return $slug;
		}

		/**
		 * Retrieve plugin data, given the plugin name.
		 *
		 * Loops through the registered plugins looking for $name. If it finds it,
		 * it returns the $data from that plugin. Otherwise, returns false.
		 *
		 * @since 2.1.0
		 *
		 * @param string $name Name of the plugin, as it was registered.
		 * @param string $data Optional. Array key of plugin data to return. Default is slug.
		 * @return string|boolean Plugin slug if found, false otherwise.
		 */
		public function _get_plugin_data_from_name( $name, $data = 'slug' ) {

function _get_plugin_data_from_name() does not seem to conform to the naming convention (^(?:[a-z]|__)[a-z_0-9]*$).

			foreach ( $this->plugins as $values ) {
				if ( $name === $values['name'] && isset( $values[ $data ] ) ) {
					return $values[ $data ];
				}
			}

			return false;
		}

		/**
		 * Retrieve the download URL for a package.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return string Plugin download URL or path to local file or empty string if undetermined.
		 */
		public function get_download_url( $slug ) {
			$dl_source = '';

			switch ( $this->plugins[ $slug ]['source_type'] ) {
				case 'repo':
					return $this->get_wp_repo_download_url( $slug );
				case 'external':
					return $this->plugins[ $slug ]['source'];
				case 'bundled':
					return $this->default_path . $this->plugins[ $slug ]['source'];
			}

			return $dl_source; // Should never happen.
		}

		/**
		 * Retrieve the download URL for a WP repo package.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return string Plugin download URL.
		 */
		protected function get_wp_repo_download_url( $slug ) {
			$source = '';
			$api    = $this->get_plugins_api( $slug );

			if ( false !== $api && isset( $api->download_link ) ) {
				$source = $api->download_link;
			}

			return $source;
		}

		/**
		 * Try to grab information from WordPress API.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return object Plugins_api response object on success, WP_Error on failure.
		 */
		protected function get_plugins_api( $slug ) {
			static $api = array(); // Cache received responses.

			if ( ! isset( $api[ $slug ] ) ) {
				if ( ! function_exists( 'plugins_api' ) ) {
					require_once ABSPATH . 'wp-admin/includes/plugin-install.php';
				}

				$response = plugins_api(
					'plugin_information',
					array(
						'slug'   => $slug,
						'fields' => array(
							'sections' => false,
						),
					)
				);

				$api[ $slug ] = false;

				if ( is_wp_error( $response ) ) {
					wp_die( esc_html( $this->strings['oops'] ) );
				} else {
					$api[ $slug ] = $response;
				}
			}

			return $api[ $slug ];
		}

		/**
		 * Retrieve a link to a plugin information page.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return string Fully formed html link to a plugin information page if available
		 *                or the plugin name if not.
		 */
		public function get_info_link( $slug ) {
			if ( ! empty( $this->plugins[ $slug ]['external_url'] ) && preg_match( self::IS_URL_REGEX, $this->plugins[ $slug ]['external_url'] ) ) {
				$link = sprintf(
					'<a href="%1$s" target="_blank">%2$s</a>',
					esc_url( $this->plugins[ $slug ]['external_url'] ),
					esc_html( $this->plugins[ $slug ]['name'] )
				);
			} elseif ( 'repo' === $this->plugins[ $slug ]['source_type'] ) {
				$url = add_query_arg(
					array(
						'tab'       => 'plugin-information',
						'plugin'    => urlencode( $slug ),
						'TB_iframe' => 'true',
						'width'     => '640',
						'height'    => '500',
					),
					self_admin_url( 'plugin-install.php' )
				);

				$link = sprintf(
					'<a href="%1$s" class="thickbox">%2$s</a>',
					esc_url( $url ),
					esc_html( $this->plugins[ $slug ]['name'] )
				);
			} else {
				$link = esc_html( $this->plugins[ $slug ]['name'] ); // No hyperlink.
			}

			return $link;
		}

		/**
		 * Determine if we're on the TGMPA Install page.
		 *
		 * @since 2.1.0
		 *
		 * @return boolean True when on the TGMPA page, false otherwise.
		 */
		protected function is_tgmpa_page() {
			return isset( $_GET['page'] ) && $this->menu === $_GET['page'];
		}

		/**
		 * Determine if we're on a WP Core installation/upgrade page.
		 *
		 * @since 2.6.0
		 *
		 * @return boolean True when on a WP Core installation/upgrade page, false otherwise.
		 */
		protected function is_core_update_page() {
			// Current screen is not always available, most notably on the customizer screen.
			if ( ! function_exists( 'get_current_screen' ) ) {
				return false;
			}

			$screen = get_current_screen();

			if ( 'update-core' === $screen->base ) {
				// Core update screen.
				return true;
			} elseif ( 'plugins' === $screen->base && ! empty( $_POST['action'] ) ) { // WPCS: CSRF ok.
				// Plugins bulk update screen.
				return true;
			} elseif ( 'update' === $screen->base && ! empty( $_POST['action'] ) ) { // WPCS: CSRF ok.
				// Individual updates (ajax call).
				return true;
			}

			return false;
		}

		/**
		 * Retrieve the URL to the TGMPA Install page.
		 *
		 * I.e. depending on the config settings passed something along the lines of:
		 * http://example.com/wp-admin/themes.php?page=tgmpa-install-plugins
		 *
		 * @since 2.5.0
		 *
		 * @return string Properly encoded URL (not escaped).
		 */
		public function get_tgmpa_url() {
			static $url;

			if ( ! isset( $url ) ) {
				$parent = $this->parent_slug;
				if ( false === strpos( $parent, '.php' ) ) {
					$parent = 'admin.php';
				}
				$url = add_query_arg(
					array(
						'page' => urlencode( $this->menu ),
					),
					self_admin_url( $parent )
				);
			}

			return $url;
		}

		/**
		 * Retrieve the URL to the TGMPA Install page for a specific plugin status (view).
		 *
		 * I.e. depending on the config settings passed something along the lines of:
		 * http://example.com/wp-admin/themes.php?page=tgmpa-install-plugins&plugin_status=install
		 *
		 * @since 2.5.0
		 *
		 * @param string $status Plugin status - either 'install', 'update' or 'activate'.
		 * @return string Properly encoded URL (not escaped).
		 */
		public function get_tgmpa_status_url( $status ) {
			return add_query_arg(
				array(
					'plugin_status' => urlencode( $status ),
				),
				$this->get_tgmpa_url()
			);
		}

		/**
		 * Determine whether there are open actions for plugins registered with TGMPA.
		 *
		 * @since 2.5.0
		 *
		 * @return bool True if complete, i.e. no outstanding actions. False otherwise.
		 */
		public function is_tgmpa_complete() {
			$complete = true;
			foreach ( $this->plugins as $slug => $plugin ) {
				if ( ! $this->is_plugin_active( $slug ) || false !== $this->does_plugin_have_update( $slug ) ) {
					$complete = false;
					break;
				}
			}

			return $complete;
		}

		/**
		 * Check if a plugin is installed. Does not take must-use plugins into account.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True if installed, false otherwise.
		 */
		public function is_plugin_installed( $slug ) {
			$installed_plugins = $this->get_plugins(); // Retrieve a list of all installed plugins (WP cached).

			return ( ! empty( $installed_plugins[ $this->plugins[ $slug ]['file_path'] ] ) );
		}

		/**
		 * Check if a plugin is active.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True if active, false otherwise.
		 */
		public function is_plugin_active( $slug ) {
			return ( ( ! empty( $this->plugins[ $slug ]['is_callable'] ) && is_callable( $this->plugins[ $slug ]['is_callable'] ) ) || is_plugin_active( $this->plugins[ $slug ]['file_path'] ) );
		}

		/**
		 * Check if a plugin can be updated, i.e. if we have information on the minimum WP version required
		 * available, check whether the current install meets them.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True if OK to update, false otherwise.
		 */
		public function can_plugin_update( $slug ) {

function can_plugin_update() does not seem to conform to the naming convention (^(?:is|has|should|may|supports)).

			// We currently can't get reliable info on non-WP-repo plugins - issue #380.
			if ( 'repo' !== $this->plugins[ $slug ]['source_type'] ) {
				return true;
			}

			$api = $this->get_plugins_api( $slug );

			if ( false !== $api && isset( $api->requires ) ) {
				return version_compare( $this->wp_version, $api->requires, '>=' );
			}

			// No usable info received from the plugins API, presume we can update.
			return true;
		}

		/**
		 * Check to see if the plugin is 'updatetable', i.e. installed, with an update available
		 * and no WP version requirements blocking it.
		 *
		 * @since 2.6.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True if OK to proceed with update, false otherwise.
		 */
		public function is_plugin_updatetable( $slug ) {
			if ( ! $this->is_plugin_installed( $slug ) ) {
				return false;
			} else {
				return ( false !== $this->does_plugin_have_update( $slug ) && $this->can_plugin_update( $slug ) );
			}
		}

		/**
		 * Check if a plugin can be activated, i.e. is not currently active and meets the minimum
		 * plugin version requirements set in TGMPA (if any).
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True if OK to activate, false otherwise.
		 */
		public function can_plugin_activate( $slug ) {

function can_plugin_activate() does not seem to conform to the naming convention (^(?:is|has|should|may|supports)).

			return ( ! $this->is_plugin_active( $slug ) && ! $this->does_plugin_require_update( $slug ) );
		}

		/**
		 * Retrieve the version number of an installed plugin.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return string Version number as string or an empty string if the plugin is not installed
		 *                or version unknown (plugins which don't comply with the plugin header standard).
		 */
		public function get_installed_version( $slug ) {
			$installed_plugins = $this->get_plugins(); // Retrieve a list of all installed plugins (WP cached).

			if ( ! empty( $installed_plugins[ $this->plugins[ $slug ]['file_path'] ]['Version'] ) ) {
				return $installed_plugins[ $this->plugins[ $slug ]['file_path'] ]['Version'];
			}

			return '';
		}

		/**
		 * Check whether a plugin complies with the minimum version requirements.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return bool True when a plugin needs to be updated, otherwise false.
		 */
		public function does_plugin_require_update( $slug ) {

function does_plugin_require_update() does not seem to conform to the naming convention (^(?:is|has|should|may|supports)).

			$installed_version = $this->get_installed_version( $slug );
			$minimum_version   = $this->plugins[ $slug ]['version'];

			return version_compare( $minimum_version, $installed_version, '>' );
		}

		/**
		 * Check whether there is an update available for a plugin.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return false|string Version number string of the available update or false if no update available.
		 */
		public function does_plugin_have_update( $slug ) {
			// Presume bundled and external plugins will point to a package which meets the minimum required version.
			if ( 'repo' !== $this->plugins[ $slug ]['source_type'] ) {
				if ( $this->does_plugin_require_update( $slug ) ) {
					return $this->plugins[ $slug ]['version'];
				}

				return false;
			}

			$repo_updates = get_site_transient( 'update_plugins' );

			if ( isset( $repo_updates->response[ $this->plugins[ $slug ]['file_path'] ]->new_version ) ) {
				return $repo_updates->response[ $this->plugins[ $slug ]['file_path'] ]->new_version;
			}

			return false;
		}

		/**
		 * Retrieve potential upgrade notice for a plugin.
		 *
		 * @since 2.5.0
		 *
		 * @param string $slug Plugin slug.
		 * @return string The upgrade notice or an empty string if no message was available or provided.
		 */
		public function get_upgrade_notice( $slug ) {
			// We currently can't get reliable info on non-WP-repo plugins - issue #380.
			if ( 'repo' !== $this->plugins[ $slug ]['source_type'] ) {
				return '';
			}

			$repo_updates = get_site_transient( 'update_plugins' );

			if ( ! empty( $repo_updates->response[ $this->plugins[ $slug ]['file_path'] ]->upgrade_notice ) ) {
				return $repo_updates->response[ $this->plugins[ $slug ]['file_path'] ]->upgrade_notice;
			}

			return '';
		}

		/**
		 * Wrapper around the core WP get_plugins function, making sure it's actually available.
		 *
		 * @since 2.5.0
		 *
		 * @param string $plugin_folder Optional. Relative path to single plugin folder.
		 * @return array Array of installed plugins with plugin information.
		 */
		public function get_plugins( $plugin_folder = '' ) {
			if ( ! function_exists( 'get_plugins' ) ) {
				require_once ABSPATH . 'wp-admin/includes/plugin.php';
			}

			return get_plugins( $plugin_folder );
		}

		/**
		 * Delete dismissable nag option when theme is switched.
		 *
		 * This ensures that the user(s) is/are again reminded via nag of required
		 * and/or recommended plugins if they re-activate the theme.
		 *
		 * @since 2.1.1
		 */
		public function update_dismiss() {
			delete_metadata( 'user', null, 'tgmpa_dismissed_notice_' . $this->id, null, true );
		}

		/**
		 * Forces plugin activation if the parameter 'force_activation' is
		 * set to true.
		 *
		 * This allows theme authors to specify certain plugins that must be
		 * active at all times while using the current theme.
		 *
		 * Please take special care when using this parameter as it has the
		 * potential to be harmful if not used correctly. Setting this parameter
		 * to true will not allow the specified plugin to be deactivated unless
		 * the user switches themes.
		 *
		 * @since 2.2.0
		 */
		public function force_activation() {
			foreach ( $this->plugins as $slug => $plugin ) {
				if ( true === $plugin['force_activation'] ) {
					if ( ! $this->is_plugin_installed( $slug ) ) {
						// Oops, plugin isn't there so iterate to next condition.
						continue;
					} elseif ( $this->can_plugin_activate( $slug ) ) {
						// There we go, activate the plugin.
						activate_plugin( $plugin['file_path'] );
					}
				}
			}
		}

		/**
		 * Forces plugin deactivation if the parameter 'force_deactivation'
		 * is set to true and adds the plugin to the 'recently active' plugins list.
		 *
		 * This allows theme authors to specify certain plugins that must be
		 * deactivated upon switching from the current theme to another.
		 *
		 * Please take special care when using this parameter as it has the
		 * potential to be harmful if not used correctly.
		 *
		 * @since 2.2.0
		 */
		public function force_deactivation() {
			$deactivated = array();

			foreach ( $this->plugins as $slug => $plugin ) {
				/*
				 * Only proceed forward if the parameter is set to true and plugin is active
				 * as a 'normal' (not must-use) plugin.
				 */
				if ( true === $plugin['force_deactivation'] && is_plugin_active( $plugin['file_path'] ) ) {
					deactivate_plugins( $plugin['file_path'] );
					$deactivated[ $plugin['file_path'] ] = time();
				}
			}

			if ( ! empty( $deactivated ) ) {
				update_option( 'recently_activated', $deactivated + (array) get_option( 'recently_activated' ) );
			}
		}

		/**
		 * Echo the current TGMPA version number to the page.
		 *
		 * @since 2.5.0
		 */
		public function show_tgmpa_version() {
			echo '<p style="float: right; padding: 0em 1.5em 0.5em 0;"><strong><small>',
				esc_html(
					sprintf(
						/* translators: %s: version number */
						__( 'TGMPA v%s', 'tgmpa' ),
						self::TGMPA_VERSION
					)
				),
				'</small></strong></p>';
		}

		/**
		 * Adds CSS to admin head.
		 *
		 * @since 2.6.2
		 */
		public function admin_css() {
			if ( ! $this->is_tgmpa_page() ) {
				return;
			}

			echo '
			<style>
			#tgmpa-plugins .tgmpa-type-required > th {
				border-left: 3px solid #dc3232;
			}
			</style>';
		}

		/**
		 * Returns the singleton instance of the class.
		 *
		 * @since 2.4.0
		 *
		 * @return \TGM_Plugin_Activation The TGM_Plugin_Activation object.

Should the return type not be TGM_Plugin_Activation?

		 */
		public static function get_instance() {
			if ( ! isset( self::$instance ) && ! ( self::$instance instanceof self ) ) {
				self::$instance = new self();
			}

			return self::$instance;
		}
	}