Ticket #15447: 15447.3.diff

wp-includes/post-thumbnail-template.php

@@ -48 +48 @@
 }
 
 /**
+ * Update cache for thumbnails in current loop
+ *
+ * @since 3.2
+ */
+function update_thumbnail_cache() {
+        global $wp_query;
+
+        // return if not at loop start
+        if ( 0 != $wp_query->current_post )
+                return;
+
+        $thumb_ids = array();
+        foreach ( $wp_query->posts as $post ) {
+                if ( $id = get_post_thumbnail_id( $post->ID ) )
+                        $thumb_ids[] = $id;
+        }
+
+        if ( ! empty( $thumb_ids ) ) {
+                get_posts( array(
+                        'update_post_term_cache' => false,
+                        'include'                => $thumb_ids,
+                        'post_type'              => 'attachment',
+                        'post_status'            => 'inherit',
+                        'nopaging'               => true,
+                ) );
+        }
+}
+
+/**
  * Retrieve Post Thumbnail.
  *
  * @since 2.9.0
@@ -57 +86 @@
  * @param string|array $attr Optional. Query string or array of attributes.
  */
 function get_the_post_thumbnail( $post_id = null, $size = 'post-thumbnail', $attr = '' ) {
+        if ( in_the_loop() )
+                update_thumbnail_cache();
+
         $post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
         $post_thumbnail_id = get_post_thumbnail_id( $post_id );
         $size = apply_filters( 'post_thumbnail_size', $size );
         if ( $post_thumbnail_id ) {
                 do_action( 'begin_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size ); // for "Just In Time" filtering of all of wp_get_attachment_image()'s filters
+
                 $html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );
                 do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );
         } else {