Bug #69796 [NEW]: mysqli_stmt::fetch doesn't assign null values to bound variables

From: theodorejb at outlook dot com Operating system: Windows 10 PHP version: master-Git-2015-06-11 (snap) Package: MySQLi related Bug Type: Bug Bug description:mysqli_stmt::fetch doesn't assign null values to bound variables Description: ------------ I used the MySQLi object-oriented API to prepare, execute, and bind results for a query using the latest PHP 7 snapshot for Windows (x86 non thread safe). While testing, I noticed a subtle yet serious bug: If one row has a non-null value for a field, and the next row has a null value for the same field, the bound variable will not be set to null when mysqli_stmt::fetch is called (it will retain its non-null value from the previous row). For example, if I have a users table with the following rows: username | age -------- | ---- user1 | 25 user2 | NULL Fetching the first row correctly binds "user1" and 25 to the variables passed to mysqli_stmt::bind_result, but after calling mysqli_stmt::fetch a second time, the variables contain "user2" and 25 (rather than "user2" and NULL). Test script: --------------- $mysqli = new mysqli("localhost", "user", "password", "database"); $stmt = $mysqli->prepare("SELECT username, age FROM users"); $stmt->execute(); $stmt->bind_result($username, $age); $stmt->fetch(); var_dump([$username, $age]); // ["user1", 25] $stmt->fetch(); var_dump([$username, $age]); // ["user2", 25] // ^ bug - array should contain ["user2", NULL] $stmt->close(); -- Edit bug report at https://bugs.php.net/bug.php?id=69796&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=69796&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=69796&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=69796&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=69796&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=69796&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=69796&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=69796&r=needscript Try newer version: https://bugs.php.net/fix.php?id=69796&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=69796&r=support Expected behavior: https://bugs.php.net/fix.php?id=69796&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=69796&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=69796&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=69796&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=69796&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=69796&r=dst IIS Stability: https://bugs.php.net/fix.php?id=69796&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=69796&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=69796&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=69796&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=69796&r=mysqlcfg