Ticket #4575: 4575.12.diff

src/wp-includes/feed-atom-comments.php

@@ -45 +45 @@
 
         <updated>
         <?php
-                $date = get_lastcommentmodified( 'GMT' );
+                $date = get_last_build_date();
                 echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date, false ) : date( 'Y-m-d\TH:i:s\Z' );
         ?>
         </updated>

src/wp-includes/feed-atom.php

@@ -32 +32 @@
 
         <updated>
         <?php
-                $date = get_lastpostmodified( 'GMT' );
+                $date = get_last_build_date();
                 echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date, false ) : date( 'Y-m-d\TH:i:s\Z' );
         ?>
         </updated>

src/wp-includes/feed-rss2-comments.php

@@ -51 +51 @@
         <description><?php bloginfo_rss( 'description' ); ?></description>
         <lastBuildDate>
         <?php
-                $date = get_lastcommentmodified( 'GMT' );
+                $date = get_last_build_date(); 
                 echo $date ? mysql2date( 'r', $date, false ) : date( 'r' );
         ?>
         </lastBuildDate>

src/wp-includes/feed-rss2.php

@@ -44 +44 @@
         <description><?php bloginfo_rss( 'description' ); ?></description>
         <lastBuildDate>
         <?php
-                $date = get_lastpostmodified( 'GMT' );
+                $date = get_last_build_date();
                 echo $date ? mysql2date( 'r', $date, false ) : date( 'r' );
         ?>
         </lastBuildDate>

src/wp-includes/feed.php

@@ -89 +89 @@
 }
 
 /**
+ * Get the timestamp of the most recently modified post from WP_Query
+ *
+ * If viewing a comment feed, the date of the most recently modified
+ * comment will be returned.
+ *
+ * @global WP_Query  $wp_query
+ *
+ * @since 5.0.0
+ *
+ * @return string The timestamp.
+ */
+function get_last_build_date() {
+        global $wp_query;
+
+        if ( ! $wp_query->have_posts() ) {
+                // Fallback to last time any post was modified or published.
+                return get_lastpostmodified( 'GMT' );
+        }
+
+        // Extract the post modified times from the posts.
+        $modified_times = wp_list_pluck( $wp_query->posts, 'post_modified_gmt' );
+
+        // If this is a comment feed, check those objects too.
+        if ( $wp_query->is_comment_feed() && $wp_query->comment_count ) {
+                // Extract the comment modified times from the comments.
+                $comment_times = wp_list_pluck( $wp_query->comments, 'comment_date_gmt' );
+
+                // Add the comment times to the post times for comparison.
+                $modified_times = array_merge( $modified_times, $comment_times );
+        }
+
+        // Determine the maximum modified time.
+        $max_modified_time = max( $modified_times );
+
+        /**
+         * Filters the date the last post or comment in the query was modified.
+         *
+         * @since 4.9.0
+         *
+         * @param string $max_modified_times Date the last post or comment was modified in the query.
+         */
+        return apply_filters( 'get_last_build_date', $max_modified_time );
+}
+
+/**
  * Retrieve the blog title for the feed title.
  *
  * @since 2.2.0

tests/phpunit/tests/feed/rss2.php

@@ -36 +36 @@
                 );
 
                 // Set a predictable time for testing date archives.
-                self::$post_date = '2003-05-27 10:07:53';
+                self::$post_date = strtotime( '2003-05-27 10:07:53' );
 
                 $count = get_option( 'posts_per_rss' ) + 1;
 
                 // Create a few posts
-                self::$posts = $factory->post->create_many(
-                        $count, array(
+                self::$posts = array();
+                for ( $i = 1; $i <= $count; $i ++ ) {
+                        self::$posts[] = $factory->post->create( array(
                                 'post_author'  => self::$user_id,
-                                'post_date'    => self::$post_date,
+                                'post_date'    => gmdate( 'Y-m-d H:i:s', self::$post_date + ( 5 * $i ) ),
+                                // Separate post dates 5 seconds apart.
                                 'post_content' => 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec velit massa, ultrices eu est suscipit, mattis posuere est. Donec vitae purus lacus. Cras vitae odio odio.',
                                 'post_excerpt' => 'Lorem ipsum dolor sit amet, consectetur adipiscing elit.',
-                        )
-                );
+                        ) );
+                }
 
                 // Assign a category to those posts
                 foreach ( self::$posts as $post ) {
@@ -89 +91 @@
         }
 
         /**
+         * Test <rss> element has correct last build date.
+         *
+         * @ticket 4575
+         */
+        function test_get_last_build_date() {
+                $this->go_to( '/?feed=rss2' );
+                $feed = $this->do_rss2();
+                $xml  = xml_to_array( $feed );
+
+                // Get the <rss> child element of <xml>.
+                $rss = xml_find( $xml, 'rss' );
+                $last_build_date = $rss[0]['child'][0]['child'][4]['content'];
+                $this->assertEquals( strtotime( get_last_build_date() ), strtotime( $last_build_date ) );
+        }
+
+        /**
          * Test the <rss> element to make sure its present and populated
          * with the expected child elements and attributes.
          */