Extend Sandboxing experiment to Paired AMP modes

assets/src/settings-page/sandboxing.js

@@ -15,7 +15,6 @@ import { CheckboxControl } from '@wordpress/components';
  */
 import { Options } from '../components/options-context-provider';
 import { AMPDrawer } from '../components/amp-drawer';
-import { STANDARD } from '../common/constants';
 
 /**
  * Component rendering the Sandboxing experiment.
@@ -27,13 +26,8 @@ export function Sandboxing( { focusedSection } ) {
 	const { updateOptions, editedOptions: {
 		sandboxing_enabled: sandboxingEnabled,
 		sandboxing_level: sandboxingLevel,
-		theme_support: themeSupport,
 	} } = useContext( Options );
 
-	if ( STANDARD !== themeSupport ) {
-		return null;
-	}
-
 	return (
 		<AMPDrawer
 			heading={ (

includes/amp-helper-functions.php

@@ -13,6 +13,7 @@
 use AmpProject\AmpWP\Option;
 use AmpProject\AmpWP\QueryVar;
 use AmpProject\AmpWP\Services;
+use AmpProject\AmpWP\Sandboxing;
 
 /**
  * Determine whether AMP is enabled on the current site.
@@ -404,7 +405,7 @@ function amp_is_available() {
 		}
 
 		$message = sprintf(
-			/* translators: 1: amp_is_available() function, 2: amp_is_request() function, 3: is_amp_endpoint() function */
+			/* translators: 1: amp_is_available function, 2: amp_is_request function, 3: is_amp_endpoint function */
 			__( '%1$s (or %2$s, formerly %3$s) was called too early and so it will not work properly.', 'amp' ),
 			'`amp_is_available()`',
 			'`amp_is_request()`',
@@ -740,10 +741,15 @@ function amp_add_amphtml_link() {
 		return;
 	}
 
-	$amp_url = amp_add_paired_endpoint( amp_get_current_url() );
+	$amp_url          = amp_add_paired_endpoint( amp_get_current_url() );
+	$sandboxing_level = amp_get_sandboxing_level();
 	if ( $amp_url ) {
 		$amp_url = remove_query_arg( QueryVar::NOAMP, $amp_url );
-		printf( '<link rel="amphtml" href="%s">', esc_url( $amp_url ) );
+		if ( 1 === $sandboxing_level || 2 === $sandboxing_level ) {
+			printf( '<link rel="alternate" type="text/html" media="only screen and (max-width: 640px)" href="%s">', esc_url( $amp_url ) );
+		} else {
+			printf( '<link rel="amphtml" href="%s">', esc_url( $amp_url ) );
+		}
 	}
 }
 
@@ -2163,3 +2169,19 @@ function amp_remove_paired_endpoint( $url ) {
 		return $url;
 	}
 }
+
+/**
+ * Determine sandboxing level if enabled.
+ *
+ * @return int Following values are possible:
+ *             0: Sandbox is disabled.
+ *             1: Sandboxing level: Loose.
+ *             2: Sandboxing level: Moderate.
+ *             3: Sandboxing level: Strict.
+ */
+function amp_get_sandboxing_level() {
+	if ( ! AMP_Options_Manager::get_option( Option::SANDBOXING_ENABLED ) ) {
+		return 0;
+	}
+	return AMP_Options_Manager::get_option( Option::SANDBOXING_LEVEL );
+}

includes/validation/class-amp-validation-manager.php

@@ -2032,6 +2032,8 @@ public static function finalize_validation( Document $dom ) {
 			return true;
 		}
 
+		$sandboxing_level = amp_get_sandboxing_level();
+
 		/*
 		 * In AMP-first, documents with invalid AMP markup can still be served. The amp attribute will be omitted in
 		 * order to prevent GSC from complaining about a validation error already surfaced inside of WordPress.
@@ -2041,8 +2043,10 @@ public static function finalize_validation( Document $dom ) {
 		 * Otherwise, if in Paired AMP then redirect to the non-AMP version if the current user isn't an user who
 		 * can manage validation error statuses (access developer tools) and change the AMP options for the template
 		 * mode. Such users should be able to see kept invalid markup on the AMP page even though it is invalid.
+		 *
+		 * Also, if sandboxing is not set to strict mode, then the page should be displayed to the user.
 		 */
-		if ( amp_is_canonical() ) {
+		if ( amp_is_canonical() || ( 1 === $sandboxing_level || 2 === $sandboxing_level ) ) {
 			return true;
 		}
 

src/MobileRedirection.php

@@ -78,6 +78,14 @@ public function register() {
 				add_filter( 'get_comments_link', [ $this, 'add_noamp_mobile_query_var' ] ); // For get_comments_link().
 				add_filter( 'respond_link', [ $this, 'add_noamp_mobile_query_var' ] ); // For comments_popup_link().
 			}
+
+			return;
+		}
+
+		// Show `Exit mobile version` link even mobile redirection is disabled and in Reader mode.
+		if ( AMP_Theme_Support::READER_MODE_SLUG === AMP_Options_Manager::get_option( Option::THEME_SUPPORT ) && $this->is_mobile_request() ) {
+			add_action( 'wp_head', [ $this, 'add_mobile_version_switcher_styles' ] );
+			add_action( 'wp_footer', [ $this, 'add_mobile_version_switcher_link' ] );
 		}
 	}
 

src/Sandboxing.php

@@ -134,19 +134,12 @@ public function sanitize_options( $options, $new_options ) {
 	 * Add hooks.
 	 */
 	public function add_hooks() {
-		// Limit to Standard mode for now. To support in Transitional/Reader we'd need to discontinue redirecting invalid
-		// AMP to non-AMP and omit the amphtml link (in which case it would only be relevant when mobile redirection is
-		// enabled).
-		if ( ! amp_is_canonical() ) {
-			return;
-		}
+		$sandboxing_level = amp_get_sandboxing_level();
 
-		if ( ! AMP_Options_Manager::get_option( Option::SANDBOXING_ENABLED ) ) {
+		if ( 0 === $sandboxing_level ) {
 			return;
 		}
 
-		$sandboxing_level = AMP_Options_Manager::get_option( Option::SANDBOXING_LEVEL );
-
 		// Opt-in to the new script sanitization logic in the script sanitizer.
 		add_filter(
 			'amp_content_sanitizers',

tests/php/test-amp-helper-functions.php

@@ -2646,4 +2646,29 @@ public static function mock_site_icon( $site_icon ) {
 		unset( $site_icon );
 		return self::MOCK_SITE_ICON;
 	}
+
+	/**
+	 * Test get sandboxing level.
+	 *
+	 * @covers ::amp_get_sandboxing_level()
+	 */
+	public function test_amp_get_sandboxing_level() {
+		// If sandboxing is disabled, then the level should be 0.
+		$this->assertEquals( 0, amp_get_sandboxing_level() );
+
+		// Enable sandboxing.
+		AMP_Options_Manager::update_option( Option::SANDBOXING_ENABLED, true );
+
+		// Enable level 1 which is Loose.
+		AMP_Options_Manager::update_option( Option::SANDBOXING_LEVEL, 1 );
+		$this->assertEquals( 1, amp_get_sandboxing_level() );
+
+		// Enable level 2 which is moderate.
+		AMP_Options_Manager::update_option( Option::SANDBOXING_LEVEL, 2 );
+		$this->assertEquals( 2, amp_get_sandboxing_level() );
+
+		// Enable level 3 which is Strict.
+		AMP_Options_Manager::update_option( Option::SANDBOXING_LEVEL, 3 );
+		$this->assertEquals( 3, amp_get_sandboxing_level() );
+	}
 }