diff --git a/src/wp-includes/user.php b/src/wp-includes/user.php
index ede1330251..748efa5181 100644
--- a/src/wp-includes/user.php
+++ b/src/wp-includes/user.php
@@ -604,9 +604,19 @@ function wp_validate_logged_in_cookie( $user_id ) {
function count_user_posts( $userid, $post_type = 'post', $public_only = false ) {
global $wpdb;
- $where = get_posts_by_author_sql( $post_type, true, $userid, $public_only );
+ $post_type = array_unique( (array) $post_type );
+ sort( $post_type );
- $count = $wpdb->get_var( "SELECT COUNT(*) FROM $wpdb->posts $where" );
+ $where = get_posts_by_author_sql( $post_type, true, $userid, $public_only );
+ $query = "SELECT COUNT(*) FROM $wpdb->posts $where";
+
+ $last_changed = wp_cache_get_last_changed( 'posts' );
+ $cache_key = 'count_user_posts:' . md5( $query ) . ':' . $last_changed;
+ $count = wp_cache_get( $cache_key, 'post-queries' );
+ if ( false === $count ) {
+ $count = $wpdb->get_var( $query );
+ wp_cache_set( $cache_key, $count, 'post-queries' );
+ }
/**
* Filters the number of posts a user has written.
diff --git a/tests/phpunit/tests/user/countUserPosts.php b/tests/phpunit/tests/user/countUserPosts.php
index dbc94f418e..64b06adda2 100644
--- a/tests/phpunit/tests/user/countUserPosts.php
+++ b/tests/phpunit/tests/user/countUserPosts.php
@@ -89,4 +89,142 @@ class Tests_User_CountUserPosts extends WP_UnitTestCase {
public function test_count_user_posts_should_ignore_non_existent_post_types() {
$this->assertSame( '4', count_user_posts( self::$user_id, array( 'foo', 'post' ) ) );
}
+
+ /**
+ * Post count be correct after reassigning posts to another user.
+ *
+ * @ticket 39242
+ */
+ public function test_reassigning_users_posts_modifies_count() {
+ // Create new user.
+ $new_user_id = self::factory()->user->create(
+ array(
+ 'role' => 'author',
+ )
+ );
+
+ // Prior to reassigning posts.
+ $this->assertSame( '4', count_user_posts( self::$user_id ), 'Original user is expected to have a count of four posts prior to reassignment.' );
+ $this->assertSame( '0', count_user_posts( $new_user_id ), 'New user is expected to have a count of zero posts prior to reassignment.' );
+
+ // Delete the original user, reassigning their posts to the new user.
+ wp_delete_user( self::$user_id, $new_user_id );
+
+ // After reassigning posts.
+ $this->assertSame( '0', count_user_posts( self::$user_id ), 'Original user is expected to have a count of zero posts following reassignment.' );
+ $this->assertSame( '4', count_user_posts( $new_user_id ), 'New user is expected to have a count of four posts following reassignment.' );
+ }
+
+ /**
+ * Post count be correct after deleting user without reassigning posts.
+ *
+ * @ticket 39242
+ */
+ public function test_post_count_retained_after_deleting_user_without_reassigning_posts() {
+ $this->assertSame( '4', count_user_posts( self::$user_id ), 'User is expected to have a count of four posts prior to deletion.' );
+
+ // Delete the original user without reassigning their posts.
+ wp_delete_user( self::$user_id );
+
+ $this->assertSame( '0', count_user_posts( self::$user_id ), 'User is expected to have a count of zero posts following deletion.' );
+ }
+
+ /**
+ * Post count should work for users that don't exist but have posts assigned.
+ *
+ * @ticket 39242
+ */
+ public function test_count_user_posts_for_non_existent_user() {
+ $next_user_id = self::$user_id + 1;
+
+ // Assign post to next user.
+ self::factory()->post->create(
+ array(
+ 'post_author' => $next_user_id,
+ 'post_type' => 'post',
+ )
+ );
+
+ $next_user_post_count = count_user_posts( $next_user_id );
+ $this->assertSame( '1', $next_user_post_count, 'Non-existent user is expected to have count of one post.' );
+ }
+
+ /**
+ * Cached user count value should be accurate after user is created.
+ *
+ * @ticket 39242
+ */
+ public function test_count_user_posts_for_user_created_after_being_assigned_posts() {
+ global $wpdb;
+ $next_user_id = (int) $wpdb->get_var( "SELECT `auto_increment` FROM INFORMATION_SCHEMA.TABLES WHERE table_name = '$wpdb->users'" );
+
+ // Assign post to next user.
+ self::factory()->post->create(
+ array(
+ 'post_author' => $next_user_id,
+ 'post_type' => 'post',
+ )
+ );
+
+ // Cache the user count.
+ count_user_posts( $next_user_id );
+
+ // Create user.
+ $real_next_user_id = self::factory()->user->create(
+ array(
+ 'role' => 'author',
+ )
+ );
+
+ $this->assertSame( $next_user_id, $real_next_user_id, 'User ID should match calculated value' );
+ $this->assertSame( '1', count_user_posts( $next_user_id ), 'User is expected to have count of one post.' );
+ }
+
+ /**
+ * User count cache should be hit regardless of post type order.
+ *
+ * @ticket 39242
+ */
+ public function test_cache_should_be_hit_regardless_of_post_type_order() {
+ // Prime Cache.
+ count_user_posts( self::$user_id, array( 'wptests_pt', 'post' ) );
+
+ $query_num_start = get_num_queries();
+ count_user_posts( self::$user_id, array( 'post', 'wptests_pt' ) );
+ $total_queries = get_num_queries() - $query_num_start;
+
+ $this->assertSame( 0, $total_queries, 'Cache should be hit regardless of post type order.' );
+ }
+
+ /**
+ * User count cache should be hit for string and array of post types.
+ *
+ * @ticket 39242
+ */
+ public function test_cache_should_be_hit_for_string_and_array_equivalent_queries() {
+ // Prime Cache.
+ count_user_posts( self::$user_id, 'post' );
+
+ $query_num_start = get_num_queries();
+ count_user_posts( self::$user_id, array( 'post' ) );
+ $total_queries = get_num_queries() - $query_num_start;
+
+ $this->assertSame( 0, $total_queries, 'Cache should be hit for string and array equivalent post types.' );
+ }
+
+ /**
+ * User count cache should be hit for array duplicates and equivalent queries.
+ *
+ * @ticket 39242
+ */
+ public function test_cache_should_be_hit_for_and_array_duplicates_equivalent_queries() {
+ // Prime Cache
+ count_user_posts( self::$user_id, array( 'post', 'post', 'post' ) );
+
+ $query_num_start = get_num_queries();
+ count_user_posts( self::$user_id, array( 'post' ) );
+ $total_queries = get_num_queries() - $query_num_start;
+
+ $this->assertSame( 0, $total_queries, 'Cache is expected to be hit for equivalent queries with duplicate post types' );
+ }
}