Prime comment meta caches in WP_Comment_Query.

The new 'update_comment_meta_cache' parameter, which defaults to `true`, can
be used to disable this behavior.

`update_comment_cache()` has been updated to support an `$update_meta_cache`
parameter, which also updates to true; this matches the pattern we use for
priming post caches.

See #16894.

git-svn-id: https://develop.svn.wordpress.org/trunk@34268 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-comment-query.php

@@ -94,7 +94,7 @@ class WP_Comment_Query {
 	 *
 	 * @since 4.2.0
 	 * @since 4.4.0 `$parent__in` and `$parent__not_in` were added.
-	 * @since 4.4.0 Order by `comment__in` was added.
+	 * @since 4.4.0 Order by `comment__in` was added. `$update_comment_meta_cache` was added.
 	 * @access public
 	 *
 	 * @param string|array $query {
@@ -161,6 +161,8 @@ class WP_Comment_Query {
 	 *     @type array        $type__in            Include comments from a given array of comment types. Default empty.
 	 *     @type array        $type__not_in        Exclude comments from a given array of comment types. Default empty.
 	 *     @type int          $user_id             Include comments for a specific user ID. Default empty.
+	 *     @type bool         $update_comment_meta_cache Whether to prime the metadata cache for found comments.
+	 *                                                   Default true.
 	 * }
 	 */
 	public function __construct( $query = '' ) {
@@ -201,6 +203,7 @@ class WP_Comment_Query {
 			'meta_value' => '',
 			'meta_query' => '',
 			'date_query' => null, // See WP_Date_Query
+			'update_comment_meta_cache' => true,
 		);
 
 		if ( ! empty( $query ) ) {
@@ -698,7 +701,7 @@ class WP_Comment_Query {
 
 		wp_cache_add( $cache_key, $comments, 'comment' );
 		if ( '*' === $fields ) {
-			update_comment_cache( $comments );
+			update_comment_cache( $comments, $this->query_vars['update_comment_meta_cache'] );
 		}
 
 		$this->comments = $comments;

src/wp-includes/comment-functions.php

@@ -2357,12 +2357,23 @@ function clean_comment_cache($ids) {
  * cache using the comment group with the key using the ID of the comments.
  *
  * @since 2.3.0
+ * @since 4.4.0 Introduced the `$update_meta_cache` parameter.
  *
- * @param array $comments Array of comment row objects
+ * @param array $comments          Array of comment row objects
+ * @param bool  $update_meta_cache Whether to update commentmeta cache. Default true.
  */
-function update_comment_cache($comments) {
+function update_comment_cache( $comments, $update_meta_cache = true ) {
 	foreach ( (array) $comments as $comment )
 		wp_cache_add($comment->comment_ID, $comment, 'comment');
+
+	if ( $update_meta_cache ) {
+		// Avoid `wp_list_pluck()` in case `$comments` is passed by reference.
+		$comment_ids = array();
+		foreach ( $comments as $comment ) {
+			$comment_ids[] = $comment->comment_ID;
+		}
+		update_meta_cache( 'comment', $comment_ids );
+	}
 }
 
 //

tests/phpunit/tests/comment/metaCache.php

@@ -4,6 +4,83 @@ class Tests_Comment_Meta_Cache extends WP_UnitTestCase {
 	protected $i = 0;
 	protected $queries = 0;
 
+	/**
+	 * @ticket 16894
+	 */
+	public function test_update_comment_meta_cache_should_default_to_true() {
+		global $wpdb;
+
+		$p = $this->factory->post->create( array( 'post_status' => 'publish' ) );
+		$comment_ids = $this->factory->comment->create_post_comments( $p, 3 );
+
+		foreach ( $comment_ids as $cid ) {
+			update_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$q = new WP_Comment_Query( array(
+			'post_ID' => $p,
+		) );
+
+		$num_queries = $wpdb->num_queries;
+		foreach ( $comment_ids as $cid ) {
+			get_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 16894
+	 */
+	public function test_update_comment_meta_cache_true() {
+		global $wpdb;
+
+		$p = $this->factory->post->create( array( 'post_status' => 'publish' ) );
+		$comment_ids = $this->factory->comment->create_post_comments( $p, 3 );
+
+		foreach ( $comment_ids as $cid ) {
+			update_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$q = new WP_Comment_Query( array(
+			'post_ID' => $p,
+			'update_comment_meta_cache' => true,
+		) );
+
+		$num_queries = $wpdb->num_queries;
+		foreach ( $comment_ids as $cid ) {
+			get_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 16894
+	 */
+	public function test_update_comment_meta_cache_false() {
+		global $wpdb;
+
+		$p = $this->factory->post->create( array( 'post_status' => 'publish' ) );
+		$comment_ids = $this->factory->comment->create_post_comments( $p, 3 );
+
+		foreach ( $comment_ids as $cid ) {
+			update_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$q = new WP_Comment_Query( array(
+			'post_ID' => $p,
+			'update_comment_meta_cache' => false,
+		) );
+
+		$num_queries = $wpdb->num_queries;
+		foreach ( $comment_ids as $cid ) {
+			get_comment_meta( $cid, 'foo', 'bar' );
+		}
+
+		$this->assertSame( $num_queries + 3, $wpdb->num_queries );
+	}
+
 	public function test_comment_meta_cache() {
 		$post_id = $this->factory->post->create( array(
 			'post_status' => 'publish'