fix: guard the Elementor promotion against older control types

CHANGELOG.md

@@ -67,6 +67,7 @@
 * Fixed featured Community Cloud snippets failing to load with some cloud API responses. (PRO)
 * Fixed bulk actions in Community Cloud running against an empty selection, so selected snippets were never downloaded.
   (PRO)
+* Fixed a fatal error in the Elementor editor on Elementor versions older than 3.19.
 
 ## [3.10.2] (2026-09-01)
 

src/php/Integration/Promotions/Other/Elementor_Editor.php

@@ -23,6 +23,10 @@ public function __construct() {
 	 * Promotion on the Custom CSS section, inside the Elementor Editor.
 	 */
 	public function promotion_in_custom_css_section() {
+		if ( ! $this->supports_notice_control() ) {
+			return;
+		}
+
 		// Elementor Core.
 		add_action(
 			'elementor/element/common/section_custom_css/after_section_start',
@@ -40,6 +44,20 @@ function ( $element ) {
 		);
 	}
 
+	/**
+	 * Check whether this version of Elementor offers the notice control type.
+	 *
+	 * The type arrived in Elementor 3.19. On anything older the constant does
+	 * not exist, and reading it while the editor builds its controls raises an
+	 * Error that leaves the editor unusable, so the promotion is skipped
+	 * rather than degraded.
+	 *
+	 * @return bool
+	 */
+	protected function supports_notice_control(): bool {
+		return defined( Controls_Manager::class . '::NOTICE' );
+	}
+
 	/**
 	 * Register promotion section in the Custom CSS section.
 	 *

tests/unit/Integration/Promotions/Other/Elementor_Editor_Test.php

@@ -0,0 +1,86 @@
+<?php
+
+namespace Code_Snippets\Integration\Promotions\Other;
+
+use Code_Snippets\UnitTestCase;
+
+/**
+ * Tests for the Elementor editor promotion.
+ *
+ * @group promotions
+ */
+class Elementor_Editor_Test extends UnitTestCase {
+
+	/**
+	 * Elementor hooks the promotion registers its controls on.
+	 */
+	private const PROMOTION_HOOKS = [
+		'elementor/element/common/section_custom_css/after_section_start',
+		'elementor/element/common/section_custom_css_pro/after_section_start',
+	];
+
+	/**
+	 * Tear down after each test.
+	 *
+	 * @return void
+	 */
+	public function tear_down() {
+		foreach ( self::PROMOTION_HOOKS as $hook ) {
+			remove_all_actions( $hook );
+		}
+
+		parent::tear_down();
+	}
+
+	/**
+	 * The promotion is left unregistered when the notice control type is absent.
+	 *
+	 * Elementor gained that control type in 3.19. Registering against an older
+	 * version reads a constant that does not exist, and the resulting Error is
+	 * raised while the editor builds its controls, leaving the editor unusable.
+	 *
+	 * Elementor is not installed for these tests, so the constant is genuinely
+	 * missing here, which is the same condition an older Elementor presents.
+	 *
+	 * @return void
+	 */
+	public function test_promotion_is_skipped_when_the_notice_control_is_missing(): void {
+		$promotion = new Elementor_Editor();
+
+		$promotion->promotion_in_custom_css_section();
+
+		foreach ( self::PROMOTION_HOOKS as $hook ) {
+			$this->assertFalse(
+				has_action( $hook ),
+				"the promotion should not be registered on $hook without the notice control type"
+			);
+		}
+	}
+
+	/**
+	 * The promotion is still registered on a version that offers the control type.
+	 *
+	 * @return void
+	 */
+	public function test_promotion_is_registered_when_the_notice_control_exists(): void {
+		$promotion = new class() extends Elementor_Editor {
+			/**
+			 * Stand in for an Elementor new enough to offer the control type.
+			 *
+			 * @return bool
+			 */
+			protected function supports_notice_control(): bool {
+				return true;
+			}
+		};
+
+		$promotion->promotion_in_custom_css_section();
+
+		foreach ( self::PROMOTION_HOOKS as $hook ) {
+			$this->assertNotFalse(
+				has_action( $hook ),
+				"the promotion should still be registered on $hook when the control type exists"
+			);
+		}
+	}
+}