Posts, Post Types: Avoid an extra database query in WP_Post for a negative post ID.

Follow-up to [21559].

Props bor0, akeda, SergeyBiryukov.
Fixes #63850.

git-svn-id: https://develop.svn.wordpress.org/trunk@60654 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/class-wp-post.php

@@ -233,7 +233,7 @@ public static function get_instance( $post_id ) {
 		global $wpdb;
 
 		$post_id = (int) $post_id;
-		if ( ! $post_id ) {
+		if ( $post_id <= 0 ) {
 			return false;
 		}
 

tests/phpunit/tests/post/wpPost.php

@@ -41,6 +41,16 @@ public function test_get_instance_should_fail_for_negative_number() {
 		$this->assertFalse( $found );
 	}
 
+	/**
+	 * @ticket 63850
+	 */
+	public function test_get_instance_should_not_perform_database_query_for_negative_number() {
+		$num_queries = get_num_queries();
+		$found       = WP_Post::get_instance( -self::$post_id );
+
+		$this->assertSame( $num_queries, get_num_queries() );
+	}
+
 	/**
 	 * @ticket 37738
 	 */