Refactor AMP modes (#2550)

* Always allow switching from Transitional to Native on sites that are defined with `add_theme_support('amp', ['paired' => true])`. Fixes #2312.
* Restore suppression of validation error warnings appearing in Reader mode. Fixes #2311
* Add functionality for users to chose AMP + Stories, AMP-only, Stories-only. Fixes #2470
* Phase out “Native” terminology in favor of “AMP-first”. Fixes #2507.

amp.php

@@ -278,7 +278,7 @@ function amp_deactivate() {
 		}
 	}
 
-	flush_rewrite_rules();
+	flush_rewrite_rules( false );
 }
 
 /*
@@ -333,38 +333,42 @@ function amp_init() {
 	 */
 	do_action( 'amp_init' );
 
-	add_rewrite_endpoint( amp_get_slug(), EP_PERMALINK );
-
 	add_filter( 'allowed_redirect_hosts', array( 'AMP_HTTP', 'filter_allowed_redirect_hosts' ) );
 	AMP_HTTP::purge_amp_query_vars();
 	AMP_HTTP::send_cors_headers();
 	AMP_HTTP::handle_xhr_request();
 	AMP_Theme_Support::init();
 	AMP_Validation_Manager::init();
-	AMP_Post_Type_Support::add_post_type_support();
-	AMP_Story_Post_Type::register();
 	AMP_Service_Worker::init();
-	add_action( 'init', array( 'AMP_Post_Type_Support', 'add_post_type_support' ), 1000 ); // After post types have been defined.
-
-	if ( defined( 'WP_CLI' ) && WP_CLI ) {
-		WP_CLI::add_command( 'amp', new AMP_CLI() );
-	}
-
-	add_filter( 'request', 'amp_force_query_var_value' );
 	add_action( 'admin_init', 'AMP_Options_Manager::register_settings' );
-	add_action( 'wp_loaded', 'amp_editor_core_blocks' );
-	add_action( 'wp_loaded', 'amp_post_meta_box' );
-	add_action( 'wp_loaded', 'amp_story_templates' );
 	add_action( 'wp_loaded', 'amp_add_options_menu' );
 	add_action( 'wp_loaded', 'amp_admin_pointer' );
-	add_action( 'parse_query', 'amp_correct_query_when_is_front_page' );
-	add_action( 'admin_bar_menu', 'amp_add_admin_bar_view_link', 100 );
+	add_action( 'wp_loaded', 'amp_post_meta_box' ); // Used in both Website and Stories experiences.
+
+	if ( AMP_Options_Manager::is_website_experience_enabled() ) {
+		add_rewrite_endpoint( amp_get_slug(), EP_PERMALINK );
+		AMP_Post_Type_Support::add_post_type_support();
+		add_action( 'init', array( 'AMP_Post_Type_Support', 'add_post_type_support' ), 1000 ); // After post types have been defined.
+		add_action( 'parse_query', 'amp_correct_query_when_is_front_page' );
+		add_action( 'admin_bar_menu', 'amp_add_admin_bar_view_link', 100 );
+		add_action( 'wp_loaded', 'amp_editor_core_blocks' );
+		add_filter( 'request', 'amp_force_query_var_value' );
+
+		// Add actions for reader mode templates.
+		add_action( 'wp', 'amp_maybe_add_actions' );
+
+		// Redirect the old url of amp page to the updated url.
+		add_filter( 'old_slug_redirect_url', 'amp_redirect_old_slug_to_new_url' );
+	}
 
-	// Redirect the old url of amp page to the updated url.
-	add_filter( 'old_slug_redirect_url', 'amp_redirect_old_slug_to_new_url' );
+	if ( AMP_Options_Manager::is_stories_experience_enabled() ) {
+		AMP_Story_Post_Type::register();
+		add_action( 'wp_loaded', 'amp_story_templates' );
+	}
 
-	// Add actions for legacy post templates.
-	add_action( 'wp', 'amp_maybe_add_actions' );
+	if ( defined( 'WP_CLI' ) && WP_CLI ) {
+		WP_CLI::add_command( 'amp', new AMP_CLI() );
+	}
 
 	/*
 	 * Broadcast plugin updates.
@@ -513,7 +517,7 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *
  *      add_theme_support( AMP_Theme_Support::SLUG );
  *
- * This will serve templates in native AMP, allowing you to use AMP components in your theme templates.
+ * This will serve templates in AMP-first, allowing you to use AMP components in your theme templates.
  * If you want to make available in transitional mode, where templates are served in AMP or non-AMP documents, do:
  *
  *      add_theme_support( AMP_Theme_Support::SLUG, array(
@@ -526,7 +530,7 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *          'template_dir' => 'amp',
  *      ) );
  *
- * If you want to have AMP-specific templates in addition to serving native AMP, do:
+ * If you want to have AMP-specific templates in addition to serving AMP-first, do:
  *
  *      add_theme_support( AMP_Theme_Support::SLUG, array(
  *          'paired'       => false,
@@ -549,16 +553,16 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *      ) );
  *
  * @see AMP_Theme_Support::read_theme_support()
- * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
+ * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is AMP-first and there is not a separate (paired) AMP URL.
  */
 function amp_is_canonical() {
 	if ( ! current_theme_supports( AMP_Theme_Support::SLUG ) ) {
 		return false;
 	}
 
 	$args = AMP_Theme_Support::get_theme_support_args();
-	if ( isset( $args['paired'] ) ) {
-		return empty( $args['paired'] );
+	if ( isset( $args[ AMP_Theme_Support::PAIRED_FLAG ] ) ) {
+		return empty( $args[ AMP_Theme_Support::PAIRED_FLAG ] );
 	}
 
 	// If there is a template_dir, then transitional mode is implied.

assets/src/block-editor/index.js

@@ -14,22 +14,31 @@ import { addAMPAttributes, addAMPExtraProps, filterBlocksEdit, filterBlocksSave
 import { getMinimumFeaturedImageDimensions } from '../common/helpers';
 import './store';
 
+const {
+	isWebsiteEnabled,
+	isStoriesEnabled,
+	isStandardMode,
+} = select( 'amp/block-editor' );
+
 const { ampLatestStoriesBlockData } = window;
 
-addFilter( 'blocks.registerBlockType', 'ampEditorBlocks/addAttributes', addAMPAttributes );
-addFilter( 'blocks.getSaveElement', 'ampEditorBlocks/filterSave', filterBlocksSave );
-addFilter( 'editor.BlockEdit', 'ampEditorBlocks/filterEdit', filterBlocksEdit, 20 );
-addFilter( 'blocks.getSaveContent.extraProps', 'ampEditorBlocks/addExtraAttributes', addAMPExtraProps );
-addFilter( 'editor.PostFeaturedImage', 'ampEditorBlocks/withFeaturedImageNotice', withFeaturedImageNotice );
-addFilter( 'editor.MediaUpload', 'ampEditorBlocks/addCroppedFeaturedImage', ( InitialMediaUpload ) => withCroppedFeaturedImage( InitialMediaUpload, getMinimumFeaturedImageDimensions() ) );
+// Add filters if AMP for Website experience is enabled.
+if ( isWebsiteEnabled() ) {
+	const plugins = require.context( './plugins', true, /.*\.js$/ );
 
-const plugins = require.context( './plugins', true, /.*\.js$/ );
+	plugins.keys().forEach( ( modulePath ) => {
+		const { name, render, icon } = plugins( modulePath );
 
-plugins.keys().forEach( ( modulePath ) => {
-	const { name, render, icon } = plugins( modulePath );
+		registerPlugin( name, { icon, render } );
+	} );
 
-	registerPlugin( name, { icon, render } );
-} );
+	addFilter( 'blocks.registerBlockType', 'ampEditorBlocks/addAttributes', addAMPAttributes );
+	addFilter( 'blocks.getSaveElement', 'ampEditorBlocks/filterSave', filterBlocksSave );
+	addFilter( 'editor.BlockEdit', 'ampEditorBlocks/filterEdit', filterBlocksEdit, 20 );
+	addFilter( 'blocks.getSaveContent.extraProps', 'ampEditorBlocks/addExtraAttributes', addAMPExtraProps );
+	addFilter( 'editor.PostFeaturedImage', 'ampEditorBlocks/withFeaturedImageNotice', withFeaturedImageNotice );
+	addFilter( 'editor.MediaUpload', 'ampEditorBlocks/addCroppedFeaturedImage', ( InitialMediaUpload ) => withCroppedFeaturedImage( InitialMediaUpload, getMinimumFeaturedImageDimensions() ) );
+}
 
 /*
  * If there's no theme support, unregister blocks that are only meant for AMP.
@@ -52,14 +61,18 @@ const blocks = require.context( './blocks', true, /(?<!test\/)index\.js$/ );
 blocks.keys().forEach( ( modulePath ) => {
 	const { name, settings } = blocks( modulePath );
 
-	// Prevent registering latest-stories block if not enabled.
-	if ( 'amp/amp-latest-stories' === name && typeof ampLatestStoriesBlockData === 'undefined' ) {
-		return;
-	}
+	const isLatestStoriesBlock = 'amp/amp-latest-stories' === name;
 
-	const blockRequiresAmp = AMP_DEPENDENT_BLOCKS.includes( name );
+	const shouldRegister = (
+		(
+			isWebsiteEnabled() && isStandardMode() && AMP_DEPENDENT_BLOCKS.includes( name )
+		) ||
+		(
+			isStoriesEnabled() && isLatestStoriesBlock && typeof ampLatestStoriesBlockData !== 'undefined'
+		)
+	);
 
-	if ( ! blockRequiresAmp || select( 'amp/block-editor' ).isNativeAMP() ) {
+	if ( shouldRegister ) {
 		registerBlockType( name, settings );
 	}
 } );

assets/src/block-editor/store/selectors.js

@@ -1,41 +1,65 @@
 /**
- * Returns the block validation errors for a given clientId.
+ * Returns whether the current theme has AMP support.
  *
- * @param {Object} state    Editor state.
- * @param {string} clientId Block client ID.
+ * @param {Object} state Editor state.
  *
- * @return {Array} Block validation errors.
+ * @return {boolean} Whether the current theme has AMP support.
  */
-export function getBlockValidationErrors( state, clientId ) {
-	return state.errorsByClientId[ clientId ] || [];
+export function hasThemeSupport( state ) {
+	return Boolean( state.hasThemeSupport );
 }
 
 /**
- * Returns whether the current theme has AMP support.
+ * Returns whether the current site is in Standard mode (AMP-first) as opposed to Transitional (paired).
  *
  * @param {Object} state Editor state.
  *
- * @return {boolean} Whether the current theme has AMP support.
+ * @return {boolean} Whether the current site is AMP-first.
  */
-export function hasThemeSupport( state ) {
-	return Boolean( state.hasThemeSupport );
+export function isStandardMode( state ) {
+	return Boolean( state.isStandardMode );
+}
+
+/**
+ * Returns whether the website experience is enabled.
+ *
+ * @param {Object} state Editor state.
+ *
+ * @return {boolean} Whether website experienced enabled.
+ */
+export function isWebsiteEnabled( state ) {
+	return Boolean( state.isWebsiteEnabled );
 }
 
 /**
- * Returns whether the current site uses native AMP.
+ * Returns whether the stories experience is enabled.
  *
  * @param {Object} state Editor state.
  *
- * @return {boolean} Whether the current site uses native AMP.
+ * @return {boolean} Whether stories experienced enabled.
  */
-export function isNativeAMP( state ) {
-	return Boolean( state.isNativeAMP );
+export function isStoriesEnabled( state ) {
+	return Boolean( state.isStoriesEnabled );
 }
 
+/**
+ * Returns the default AMP status.
+ *
+ * @param {Object} state Editor state.
+ *
+ * @return {string} The default AMP status.
+ */
 export function getDefaultStatus( state ) {
 	return state.defaultStatus;
 }
 
+/**
+ * Returns the possible AMP statuses.
+ *
+ * @param {Object} state Editor state.
+ *
+ * @return {string[]} The possible AMP statuses, 'enabled' and 'disabled'.
+ */
 export function getPossibleStatuses( state ) {
 	return state.possibleStatuses;
 }

assets/src/block-editor/store/test/selectors.js

@@ -2,11 +2,47 @@
  * Internal dependencies
  */
 import {
+	hasThemeSupport,
+	isStandardMode,
+	isWebsiteEnabled,
+	isStoriesEnabled,
 	getDefaultStatus,
 	getPossibleStatuses,
 } from '../selectors';
 
 describe( 'selectors', () => {
+	describe( 'hasThemeSupport', () => {
+		it( 'should return whether the theme has AMP support', () => {
+			const state = { hasThemeSupport: false };
+
+			expect( hasThemeSupport( state ) ).toBe( false );
+		} );
+	} );
+
+	describe( 'isStandardMode', () => {
+		it( 'should return whether standard mode is enabled', () => {
+			const state = { isStandardMode: true };
+
+			expect( isStandardMode( state ) ).toBe( true );
+		} );
+	} );
+
+	describe( 'isWebsiteEnabled', () => {
+		it( 'should return whether the website format is enabled', () => {
+			const state = { isWebsiteEnabled: false };
+
+			expect( isWebsiteEnabled( state ) ).toBe( false );
+		} );
+	} );
+
+	describe( 'isStoriesEnabled', () => {
+		it( 'should return whether the stories format is enabled', () => {
+			const state = { isStoriesEnabled: false };
+
+			expect( isStoriesEnabled( state ) ).toBe( false );
+		} );
+	} );
+
 	describe( 'getDefaultStatus', () => {
 		it( 'should return the default AMP status', () => {
 			const state = { defaultStatus: 'enabled' };