From 48f17267fb018427506b5d59e9e108dfd9131eb1 Mon Sep 17 00:00:00 2001
From: Peter Wilson <peterwilsoncc@git.wordpress.org>
Date: Fri, 9 Sep 2022 02:04:18 +0000
Subject: [PATCH] Query: Improve `WP_Query`'s cache key generation for taxonomy
 queries.

Modify how `WP_Query` determines whether a database query contains a taxonomy component and accounts for term changes when generating the cache key. This presents a stale cache been used under some circumstances.

Props Chouby, costdev, peterwilsoncc.
See #22176.



git-svn-id: https://develop.svn.wordpress.org/trunk@54111 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-wp-query.php         |  2 +-
 tests/phpunit/tests/query/cacheResults.php | 91 ++++++++++++++++++++++
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 214d18fda8..32b5fafaf3 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3094,7 +3094,7 @@ class WP_Query {
 			$key         = md5( serialize( $cache_args ) . $new_request );
 
 			$last_changed = wp_cache_get_last_changed( 'posts' );
-			if ( ! empty( $this->tax_query->queried_terms ) ) {
+			if ( ! empty( $this->tax_query->queries ) ) {
 				$last_changed .= wp_cache_get_last_changed( 'terms' );
 			}
 
diff --git a/tests/phpunit/tests/query/cacheResults.php b/tests/phpunit/tests/query/cacheResults.php
index 226e82aeca..d93b5ae9f1 100644
--- a/tests/phpunit/tests/query/cacheResults.php
+++ b/tests/phpunit/tests/query/cacheResults.php
@@ -2,6 +2,7 @@
 
 /**
  * @group query
+ * @covers WP_Query::get_posts
  */
 class Test_Query_CacheResults extends WP_UnitTestCase {
 	/**
@@ -893,4 +894,94 @@ class Test_Query_CacheResults extends WP_UnitTestCase {
 		$this->assertEmpty( $posts2 );
 		$this->assertNotSame( $query1->found_posts, $query2->found_posts );
 	}
+
+	/**
+	 * @ticket 22176
+	 */
+	public function test_query_cache_should_exclude_post_with_excluded_term() {
+		$term_id = self::$t1;
+		// Post 0 has the term applied
+		$post_id = self::$posts[0];
+
+		$args = array(
+			'fields'    => 'ids',
+			'tax_query' => array(
+				array(
+					'taxonomy' => 'category',
+					'terms'    => array( $term_id ),
+					'operator' => 'NOT IN',
+				),
+			),
+		);
+
+		$post_ids_q1 = get_posts( $args );
+		$this->assertNotContains( $post_id, $post_ids_q1, 'First query includes the post ID.' );
+
+		$num_queries = get_num_queries();
+		$post_ids_q2 = get_posts( $args );
+		$this->assertNotContains( $post_id, $post_ids_q2, 'Second query includes the post ID.' );
+
+		$this->assertSame( $num_queries, get_num_queries(), 'Second query is not cached.' );
+	}
+
+	/**
+	 * @ticket 22176
+	 */
+	public function test_query_cache_should_exclude_post_when_excluded_term_is_added_after_caching() {
+		$term_id = self::$t1;
+		// Post 1 does not have the term applied.
+		$post_id = self::$posts[1];
+
+		$args = array(
+			'fields'    => 'ids',
+			'tax_query' => array(
+				array(
+					'taxonomy' => 'category',
+					'terms'    => array( $term_id ),
+					'operator' => 'NOT IN',
+				),
+			),
+		);
+
+		$post_ids_q1 = get_posts( $args );
+		$this->assertContains( $post_id, $post_ids_q1, 'First query does not include the post ID.' );
+
+		wp_set_object_terms( $post_id, array( $term_id ), 'category' );
+
+		$num_queries = get_num_queries();
+		$post_ids_q2 = get_posts( $args );
+		$this->assertNotContains( $post_id, $post_ids_q2, 'Second query includes the post ID.' );
+		$this->assertNotSame( $num_queries, get_num_queries(), 'Applying term does not invalidate previous cache.' );
+	}
+
+	/**
+	 * @ticket 22176
+	 */
+	public function test_query_cache_should_not_exclude_post_when_excluded_term_is_removed_after_caching() {
+		$term_id = self::$t1;
+		// Post 0 has the term applied.
+		$post_id = self::$posts[0];
+
+		$args = array(
+			'fields'    => 'ids',
+			'tax_query' => array(
+				array(
+					'taxonomy' => 'category',
+					'terms'    => array( $term_id ),
+					'operator' => 'NOT IN',
+				),
+			),
+		);
+
+		$post_ids_q1 = get_posts( $args );
+		$this->assertNotContains( $post_id, $post_ids_q1, 'First query includes the post ID.' );
+
+		// Clear the post of terms.
+		wp_set_object_terms( $post_id, array(), 'category' );
+
+		$num_queries = get_num_queries();
+		$post_ids_q2 = get_posts( $args );
+		$this->assertContains( $post_id, $post_ids_q2, 'Second query does not include the post ID.' );
+		$this->assertNotSame( $num_queries, get_num_queries(), 'Removing term does not invalidate previous cache.' );
+	}
 }