Reduce frontend PHP bootstrap memory further

classes/Admin.php

@@ -19,16 +19,20 @@ public static function init() {
 			PUM_Admin_Notices::init();
 		}
 
-		PUM_Admin_Popups::init();
-		PUM_Admin_Themes::init();
-
 		if ( is_admin() ) {
+			PUM_Admin_Popups::init();
+			PUM_Admin_Themes::init();
 			PUM_Admin_Subscribers::init();
 			PUM_Admin_Settings::init();
 			PUM_Admin_Tools::init();
 			PUM_Admin_Shortcode_UI::init();
 			PUM_Upsell::init();
 			PUM_Admin_Onboarding::init();
+		} else {
+			// Preserve programmatic saves without loading the editor classes on every frontend request.
+			add_action( 'save_post', [ 'PUM_Admin_Popups', 'save' ], 10, 2 );
+			add_filter( 'wp_insert_post_data', [ 'PUM_Admin_Popups', 'set_slug' ], 99, 2 );
+			add_action( 'save_post', [ 'PUM_Admin_Themes', 'save' ], 10, 2 );
 		}
 
 		add_filter( 'user_has_cap', [ __CLASS__, 'prevent_default_theme_deletion' ], 10, 3 );

classes/Plugin/Core.php

@@ -348,14 +348,14 @@ protected function init_services() {
 		$form_conversion_tracking->init();
 
 		/*
-		 * Defer notifications orchestrator init until WordPress's `init`
+		 * Defer notification bootstrap until WordPress's `init`
 		 * action. Core loads on plugins_loaded@11, but addons (Pro, Pro+,
 		 * integrations) load at priority 12+ and need a window to register
-		 * their own providers via the `popup_maker/notification_providers`
-		 * filter before the Manager resolves the provider list.
+		 * their own providers and deferred trigger hooks before the Manager
+		 * resolves the provider list or registers frontend lazy boot hooks.
 		 */
 		add_action( 'init', function () {
-			$this->get( 'notifications' )->init();
+			$this->get( 'notifications' )->register_lazy_boot();
 		}, 5 );
 	}
 

classes/Services/Notifications/Manager.php

@@ -67,6 +67,7 @@ public function init() {
 		if ( $this->booted ) {
 			return;
 		}
+
 		$this->booted = true;
 
 		$this->providers = $this->resolve_providers();
@@ -78,6 +79,72 @@ public function init() {
 		}
 	}
 
+	/**
+	 * Boot notifications immediately in wp-admin or defer them to relevant frontend hooks.
+	 *
+	 * @return void
+	 */
+	public function register_lazy_boot() {
+		if ( is_admin() ) {
+			$this->init();
+			return;
+		}
+
+		foreach ( $this->get_deferred_boot_hooks() as $hook ) {
+			if ( did_action( $hook ) || did_filter( $hook ) ) {
+				// The event already fired earlier in this request — e.g. an
+				// upgrade dispatches popup_maker/update_version during
+				// plugins_loaded, before this registration runs on init.
+				$this->init();
+				return;
+			}
+
+			add_filter( $hook, [ $this, 'boot_on_demand' ], PHP_INT_MIN );
+		}
+	}
+
+	/**
+	 * Get hooks that can trigger lazy notification boot on frontend requests.
+	 *
+	 * Extensions (Pro, Pro+, legacy) can append their own trigger hooks via the
+	 * `popup_maker/notifications/deferred_boot_hooks` filter. Any consumer that
+	 * calls get_providers() boots the manager regardless, so this filter is an
+	 * optimization and not a correctness requirement.
+	 *
+	 * @return string[]
+	 */
+	protected function get_deferred_boot_hooks() {
+		$defaults = [
+			'popup_maker/update_version',
+			'pum_alert_list',
+			'pum_alert_dismissed',
+			'save_post_popup',
+			'save_post_pum_cta',
+			'deleted_post',
+			'trashed_post',
+			'untrashed_post',
+			'update_option_pum_form_conversion_count',
+			'update_option_pum_total_conversion_count',
+			'update_option_pum_bypass_adblockers',
+			'activated_plugin',
+			'deactivated_plugin',
+		];
+
+		return apply_filters( 'popup_maker/notifications/deferred_boot_hooks', $defaults );
+	}
+
+	/**
+	 * Boot notification providers when a frontend request reaches a relevant hook.
+	 *
+	 * @param mixed $value Current filter value, if any.
+	 * @return mixed
+	 */
+	public function boot_on_demand( $value = null ) {
+		$this->init();
+
+		return $value;
+	}
+
 	/**
 	 * Currently booted providers.
 	 *
@@ -87,6 +154,8 @@ public function init() {
 	 * @return array<int,Provider>
 	 */
 	public function get_providers() {
+		$this->init();
+
 		return $this->providers;
 	}
 

classes/Services/Notifications/Provider.php

@@ -16,9 +16,9 @@
  * entries to the `pum_alert_list` filter and optionally reacts to
  * dismissals, version changes, or other plugin events.
  *
- * Providers are booted once during plugin load via
- * `Notifications::init()` — each is given the opportunity to wire its own
- * hooks inside its `init()` method.
+ * Providers are booted once via `Notifications::init()` — each is given the
+ * opportunity to wire its own hooks inside its `init()` method. Frontend
+ * requests may defer that boot until a notification-related event.
  *
  * @since 1.23.0
  */

includes/legacy/class-popup-maker.php

@@ -169,21 +169,42 @@ public function init() {
 		PUM_Utils_Upgrades::instance();
 		PUM_Newsletters::init();
 		PUM_Integrations::init();
-		PUM_Privacy::init();
-
-		PUM_Utils_Alerts::init();
+		$this->register_deferred_hooks();
 
 		PUM_Shortcode_Popup::init();
 		PUM_Shortcode_PopupTrigger::init();
 		PUM_Shortcode_PopupClose::init();
 		PUM_Shortcode_PopupCookie::init();
 		PUM_Shortcode_CallToAction::init();
 
-		PUM_Telemetry::init();
-
 		new PUM_Extensions();
 	}
 
+	/**
+	 * Register hooks whose handlers are not needed during normal frontend bootstrap.
+	 *
+	 * String callbacks preserve the existing hooks while allowing WordPress to
+	 * autoload each implementation only when its hook runs.
+	 *
+	 * @return void
+	 */
+	private function register_deferred_hooks() {
+		add_filter( 'wp_privacy_personal_data_exporters', [ 'PUM_Privacy', 'register_exporter' ], 10 );
+		add_filter( 'wp_privacy_personal_data_erasers', [ 'PUM_Privacy', 'register_erasers' ], 10 );
+		add_action( 'admin_init', [ 'PUM_Privacy', 'privacy_policy_content' ], 20 );
+		add_action( 'pum_save_popup', [ 'PUM_Privacy', 'clear_cookie_list' ] );
+
+		add_action( 'admin_init', [ 'PUM_Utils_Alerts', 'hooks' ] );
+		add_action( 'admin_init', [ 'PUM_Utils_Alerts', 'php_handler' ] );
+		add_action( 'wp_ajax_pum_alerts_action', [ 'PUM_Utils_Alerts', 'ajax_handler' ] );
+		add_filter( 'pum_alert_list', [ 'PUM_Utils_Alerts', 'translation_request' ], 10 );
+		add_action( 'admin_menu', [ 'PUM_Utils_Alerts', 'append_alert_count' ], 999 );
+
+		add_action( 'pum_daily_scheduled_events', [ 'PUM_Telemetry', 'track_check' ] );
+		add_filter( 'pum_alert_list', [ 'PUM_Telemetry', 'optin_alert' ] );
+		add_action( 'pum_alert_dismissed', [ 'PUM_Telemetry', 'optin_alert_check' ], 10, 2 );
+	}
+
 	/**
 	 * Returns true when debug mode is enabled.
 	 *

tests/php/fixtures/class-pum-test-deferred-notification-provider.php

@@ -0,0 +1,26 @@
+<?php
+/**
+ * Test provider used to verify hooks added during an active filter still run.
+ *
+ * @package Popup_Maker
+ */
+
+class PUM_Test_Deferred_Notification_Provider implements \PopupMaker\Services\Notifications\Provider {
+
+	/**
+	 * @return void
+	 */
+	public function init() {
+		add_filter( 'pum_alert_list', [ $this, 'add_alert' ], PHP_INT_MIN + 1 );
+	}
+
+	/**
+	 * @param array $alerts Registered alerts.
+	 * @return array
+	 */
+	public function add_alert( $alerts ) {
+		$alerts[] = [ 'code' => 'deferred_test_provider' ];
+
+		return $alerts;
+	}
+}

tests/php/tests/Notification_Manager_Loader_Test.php

@@ -0,0 +1,134 @@
+<?php
+/**
+ * Tests for on-demand notification provider loading.
+ *
+ * @package Popup_Maker
+ */
+
+require_once dirname( __DIR__ ) . '/fixtures/class-pum-test-deferred-notification-provider.php';
+
+/**
+ * Verify frontend requests load notification providers when needed.
+ */
+class Notification_Manager_Loader_Test extends WP_UnitTestCase {
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 *
+	 * @return void
+	 */
+	public function test_alert_filter_boots_deferred_providers_in_current_iteration() {
+		$manager  = new \PopupMaker\Services\Notifications\Manager( \PopupMaker\plugin() );
+		$provider = new PUM_Test_Deferred_Notification_Provider();
+
+		$this->assertFalse( is_admin() );
+
+		add_filter(
+			'popup_maker/notification_providers',
+			static function ( $providers ) use ( $provider ) {
+				$providers[] = $provider;
+				return $providers;
+			}
+		);
+		$manager->register_lazy_boot();
+
+		$alerts = apply_filters( 'pum_alert_list', [] );
+		$codes  = wp_list_pluck( $alerts, 'code' );
+
+		$this->assertContains( 'deferred_test_provider', $codes );
+		$this->assertContains( $provider, $manager->get_providers() );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 *
+	 * @return void
+	 */
+	public function test_custom_deferred_boot_hook_boots_the_manager_on_frontend() {
+		$manager     = new \PopupMaker\Services\Notifications\Manager( \PopupMaker\plugin() );
+		$provider    = new PUM_Test_Deferred_Notification_Provider();
+		$custom_hook = 'pum_test_custom_deferred_notification_boot';
+
+		$this->assertFalse( is_admin() );
+
+		add_filter(
+			'popup_maker/notification_providers',
+			static function ( $providers ) use ( $provider ) {
+				$providers[] = $provider;
+				return $providers;
+			}
+		);
+
+		add_filter(
+			'popup_maker/notifications/deferred_boot_hooks',
+			static function ( $hooks ) use ( $custom_hook ) {
+				$hooks[] = $custom_hook;
+				return $hooks;
+			}
+		);
+
+		$manager->register_lazy_boot();
+
+		$this->assertSame( 'original-value', apply_filters( $custom_hook, 'original-value' ) );
+		$this->assertSame( PHP_INT_MIN + 1, has_filter( 'pum_alert_list', [ $provider, 'add_alert' ] ) );
+		$this->assertContains( $provider, $manager->get_providers() );
+	}
+
+	/**
+	 * An upgrade fires popup_maker/update_version during plugins_loaded,
+	 * before init@5 registers lazy boot — the manager must boot immediately
+	 * when a deferred hook already fired earlier in the request.
+	 *
+	 * @return void
+	 */
+	public function test_lazy_boot_inits_immediately_when_deferred_hook_already_fired() {
+		$manager  = new \PopupMaker\Services\Notifications\Manager( \PopupMaker\plugin() );
+		$provider = new PUM_Test_Deferred_Notification_Provider();
+
+		$this->assertFalse( is_admin() );
+
+		add_filter(
+			'popup_maker/notification_providers',
+			static function ( $providers ) use ( $provider ) {
+				$providers[] = $provider;
+				return $providers;
+			}
+		);
+
+		// Simulate the upgrade action firing before register_lazy_boot runs.
+		do_action( 'popup_maker/update_version', '1.0.0', '0.9.0' );
+
+		$manager->register_lazy_boot();
+
+		$this->assertContains( $provider, $manager->get_providers() );
+	}
+
+	/**
+	 * Core must wire the Manager's lazy boot on init — verify through the
+	 * real booted plugin rather than a locally constructed manager.
+	 *
+	 * @return void
+	 */
+	public function test_core_registers_manager_lazy_boot_on_init() {
+		$manager = \PopupMaker\plugin( 'notifications' );
+
+		// Core's wiring results in one of two valid states: deferred boot
+		// filters registered, or an immediate boot because a deferred hook
+		// (e.g. popup_maker/update_version on a fresh install) already fired.
+		$deferred = false !== has_filter( 'pum_alert_list', [ $manager, 'boot_on_demand' ] );
+
+		$booted_prop = new ReflectionProperty( $manager, 'booted' );
+
+		if ( PHP_VERSION_ID < 80100 ) {
+			// Required before PHP 8.1, deprecated no-op on PHP 8.5+.
+			$booted_prop->setAccessible( true );
+		}
+
+		$this->assertTrue(
+			$deferred || $booted_prop->getValue( $manager ),
+			'Core should register the real manager for deferred boot on frontend requests.'
+		);
+	}
+}

tests/php/tests/PUM_Admin_Loader_Test.php

@@ -50,12 +50,18 @@ public function tearDown(): void {
 	}
 
 	/**
+	 * Frontend bootstrap defers the heavy editor classes until their save hooks run.
+	 *
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 *
 	 * @return void
 	 */
 	public function test_frontend_loads_only_cross_context_admin_hooks() {
 		$this->assertFalse( is_admin() );
 		$this->assertSame( 10, has_action( 'save_post', [ 'PUM_Admin_Popups', 'save' ] ) );
 		$this->assertSame( 10, has_action( 'save_post', [ 'PUM_Admin_Themes', 'save' ] ) );
+		$this->assertSame( 99, has_filter( 'wp_insert_post_data', [ 'PUM_Admin_Popups', 'set_slug' ] ) );
 		$this->assertSame( 10, has_action( 'enqueue_block_assets', [ 'PUM_Admin_BlockEditor', 'register_block_assets' ] ) );
 		$this->assertFalse( has_action( 'admin_menu', [ 'PUM_Admin_Pages', 'register_pages' ] ) );
 		$this->assertFalse( has_action( 'wp_ajax_pum_object_search', [ 'PUM_Admin_Ajax', 'object_search' ] ) );