mysqli + xdebug breakpoint after closing statement result in many warnings

Question

I have a piece of code like this:

$conn = new mysqli($host, $username, $passwd, $dbname);  ...  $stmt = $conn->prepare('SELECT ...'); $stmt->bind_param(...); $stmt->execute(); $stmt->bind_result(...); while($stmt->fetch()) {     // do something here } $stmt->close();  ...  // do something more here that has absolutely nothing to do with $stmt 

This works perfectly fine. I get the results I expected, there are no errors or anything that is not supposed to happen.

But if I set a break point (Xdebug 2.2.5 / 2.2.6 / 2.2.8 / 2.3.2 and PHP 5.5.3 / 5.5.15 / 5.6.0 / 5.6.6 / 5.6.10) to a line after $stmt->close();, I get many warnings like

Property access is not allowed yet

or

Couldn't fetch mysqli_stmt

I thought I missed to close another mysqli statement, but I get all results. There seems to be just no problem in my code...

Is there a way to get rid of this wrong warnings?

Update: This problem still exist in PHP 7.0.1 / Xdebug 2.4.0 RC3.

Answer 1

There are some similar issues reported
http://bugs.xdebug.org/view.php?id=900
https://bugs.php.net/bug.php?id=60778

One way to get rid of this messages is to add

unset($stmt); 

after closing the statement and before the breakpoint. If this does not help, you should also add

unset($connection); 

after closing the connection as mentioned by @Martin in the comments.

This does not solve the problem itself, but let you go on with your work until this may be fixed some time.

EDIT: Now there is also a reported issue :)

EDIT: This seems to be a bug in the MySQLi driver as reported here.

EDIT: Looks like this bug does not appear if you use PDO. So this is maybe an other reason to switch to PDO.

Answer 2

FWIW, this was a bug in PHP (https://bugs.php.net/bug.php?id=67348&edit=1), which should be fixed for PHP 7.4: https://github.com/php/php-src/commit/579562176b71820ad49d43b2c841642fef12fe57