Opt to inline the descending-ordering comment logic since temporary

amp.php

@@ -88,17 +88,14 @@ function amp_after_setup_theme() {
 	}
 
 	add_action( 'init', 'amp_init' );
-	add_action( 'widgets_init', 'AMP_Theme_Support::register_widgets' );
+	add_action( 'widgets_init', 'AMP_Theme_Support::register_widgets' ); // @todo Let this be called by AMP_Theme_Support::init().
+	add_action( 'init', 'AMP_Theme_Support::setup_commenting' ); // @todo Let this be called by AMP_Theme_Support::init().
 	add_action( 'admin_init', 'AMP_Options_Manager::register_settings' );
 	add_filter( 'amp_post_template_analytics', 'amp_add_custom_analytics' );
 	add_action( 'wp_loaded', 'amp_post_meta_box' );
 	add_action( 'wp_loaded', 'amp_add_options_menu' );
 	add_action( 'parse_query', 'amp_correct_query_when_is_front_page' );
 	AMP_Post_Type_Support::add_post_type_support();
-	add_filter( 'option_comment_order', function() {
-		return 'desc';
-	}, PHP_INT_MAX );
-	add_action( 'admin_print_footer_scripts-options-discussion.php', 'amp_comments_order_disable_scripts' );
 }
 add_action( 'after_setup_theme', 'amp_after_setup_theme', 5 );
 

includes/admin/functions.php

@@ -162,7 +162,7 @@ function amp_comments_order_disable_scripts() {
 		true
 	);
 	?>
-	<div class="notice notice-info inline" id="amp-comment-notice"><p><?php echo wp_kses_post( __( 'Note: AMP does not yet <a href="https://github.com/ampproject/amphtml/issues/5396" target="_blank">support ascending</a> comments with newer entries appearing at the bottom.', 'amp' ) ); ?></p></div>
+
 	<?php
 }
 

includes/class-amp-theme-support.php

@@ -258,6 +258,39 @@ public static function purge_amp_query_vars() {
 		}
 	}
 
+	/**
+	 * Set up commenting.
+	 */
+	public static function setup_commenting() {
+		if ( ! current_theme_supports( AMP_QUERY_VAR ) ) {
+			return;
+		}
+
+		/*
+		 * Temporarily force comments to be listed in descending order.
+		 *
+		 * The following hooks are temporary while waiting for amphtml#5396 to be resolved.
+		 */
+		add_filter( 'option_comment_order', function() {
+			return 'desc';
+		}, PHP_INT_MAX );
+
+		add_action( 'admin_print_footer_scripts-options-discussion.php', function() {
+			?>
+			<div class="notice notice-info inline" id="amp-comment-notice"><p><?php echo wp_kses_post( __( 'Note: AMP does not yet <a href="https://github.com/ampproject/amphtml/issues/5396" target="_blank">support ascending</a> comments with newer entries appearing at the bottom.', 'amp' ) ); ?></p></div>
+			<script>
+			// Move the notice below the selector and disable selector.
+			jQuery( function( $ ) {
+				var orderSelect = $( '#comment_order' ),
+					notice = $( '#amp-comment-notice' );
+				orderSelect.prop( 'disabled', true );
+				orderSelect.closest( 'fieldset' ).append( notice );
+			} );
+			</script>
+			<?php
+		} );
+	}
+
 	/**
 	 * Register/override widgets.
 	 *