From 37a8fe8b9b22268965f652fe8a34de626050c696 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Sun, 30 Jul 2017 14:55:17 +0000
Subject: [PATCH] Comments: Ignore the 'fields' parameter in the comment query
 cache.

`WP_Comment_Query` always queries runs an ID query, and so is unaffected
by the 'fields' parameter. As such, 'fields' can be ignored when building
a cache key for the results of the ID query.

Props spacedmonkey.
Fixes #41348.

git-svn-id: https://develop.svn.wordpress.org/trunk@41190 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-wp-comment-query.php | 11 +++-
 tests/phpunit/tests/comment/query.php      | 74 ++++++++++++++++++++++
 2 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 4365e1753f..c67584c908 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -375,10 +375,15 @@ class WP_Comment_Query {
 			$this->meta_query_clauses = $this->meta_query->get_sql( 'comment', $wpdb->comments, 'comment_ID', $this );
 		}
 
-		// $args can include anything. Only use the args defined in the query_var_defaults to compute the key.
-		$key = md5( serialize( wp_array_slice_assoc( $this->query_vars, array_keys( $this->query_var_defaults ) ) ) );
-		$last_changed = wp_cache_get_last_changed( 'comment' );
+		/*
+		 * Only use the args defined in the query_var_defaults to compute the key,
+		 * but ignore 'fields', which does not affect query results.
+		 */
+		$_args = wp_array_slice_assoc( $this->query_vars, array_keys( $this->query_var_defaults ) );
+		unset( $_args['fields'] );
 
+		$key = md5( serialize( $_args ) );
+		$last_changed = wp_cache_get_last_changed( 'comment' );
 
 		$cache_key   = "get_comments:$key:$last_changed";
 		$cache_value = wp_cache_get( $cache_key, 'comment' );
diff --git a/tests/phpunit/tests/comment/query.php b/tests/phpunit/tests/comment/query.php
index 60e111d544..1d17603f86 100644
--- a/tests/phpunit/tests/comment/query.php
+++ b/tests/phpunit/tests/comment/query.php
@@ -2877,4 +2877,78 @@ class Tests_Comment_Query extends WP_UnitTestCase {
 		$this->assertSame( $num_queries, $wpdb->num_queries );
 		$this->assertEqualSets( array( $c ), $q->comments );
 	}
+
+	/**
+	 * @ticket 41348
+	 */
+	public function test_count_query_should_miss_noncount_cache() {
+		global $wpdb;
+
+		$q = new WP_Comment_Query();
+
+		$query_1 = $q->query( array(
+			'fields' => 'ids',
+			'number' => 3,
+			'order' => 'ASC',
+		) );
+
+		$number_of_queries = $wpdb->num_queries;
+
+		$query_2 = $q->query( array(
+			'fields' => 'ids',
+			'number' => 3,
+			'order' => 'ASC',
+			'count' => true,
+		) );
+		$this->assertEquals( $number_of_queries + 1, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 41348
+	 */
+	public function test_count_query_should_hit_count_cache() {
+		global $wpdb;
+
+		$q = new WP_Comment_Query();
+
+		$query_1 = $q->query( array(
+			'fields' => 'ids',
+			'number' => 3,
+			'order' => 'ASC',
+			'count' => true,
+		) );
+		$number_of_queries = $wpdb->num_queries;
+
+		$query_2 = $q->query( array(
+			'fields' => 'ids',
+			'number' => 3,
+			'order' => 'ASC',
+			'count' => true,
+		) );
+		$this->assertEquals( $number_of_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 41348
+	 */
+	public function test_different_values_of_fields_should_share_cached_values() {
+		global $wpdb;
+
+		$q = new WP_Comment_Query();
+
+		$query_1 = $q->query( array(
+			'fields' => 'all',
+			'number' => 3,
+			'order' => 'ASC',
+		) );
+		$number_of_queries = $wpdb->num_queries;
+
+		$query_2 = $q->query( array(
+			'fields' => 'ids',
+			'number' => 3,
+			'order' => 'ASC',
+		) );
+
+		$this->assertEquals( $number_of_queries, $wpdb->num_queries );
+	}
 }