php 7.1 media uploader bug

[drrobotnik]

In PHP7.1, when you upload a file with the same name multiple times there is a PHP Warning: A non-numeric value encountered in /wp-includes/functions.php on line 2077.

The warning is a type casting related. All you need to do to fix is change the default string value to null.

I've included a very tiny patch and have tested that it fixes the issue and has no backwards compatibility implications.

[drrobotnik]

wp-includes/functions.php, changes default type to null in order to fix bug in WP while using PHP 7.1

[SergeyBiryukov]

Hi @drrobotnik, thanks for the ticket and the patch!

$number = '' was added in [3255] and has not changed since then.

Shouldn't it be $number = 0 instead of null though?

[drrobotnik]

Hey @SergeyBiryukov,

Null shouldn't hurt anything, but yeah that makes sense. I was looking at an empty string and thinking unset.

I've attached the updated patch.

While I was testing the change I came across another issue a few lines down:

PHP Fatal error: Maximum execution time of 30 seconds exceeded in /wp-includes/functions.php on line 2098

<?php
while ( file_exists( $dir . "/$filename" ) ) {
    if ( '' === "$number$ext" ) {
        $filename = "$filename-" . ++$number;
    } else {
        $filename = str_replace( array( "-$number$ext", "$number$ext" ), "-" . ++$number . $ext, $filename );
    }
}

It was fixed by changing while() to if(). I see a few of these in functions.php. What's odd was it only happened when I uploaded a gif (963 KB), but not when I uploaded a jpg (1.3 MB). Should I open a separate ticket?

[drrobotnik]

updated patch changes null to 0.

[SergeyBiryukov]

Ah, I was wrong, we can't set $number to 0, because it needs to be an empty string on first iteration. Otherwise, it causes the infinite loop issue that you experienced.

functions.diff​ works fine, I'd just like to make the type casting explicit just in case.

39774.patch​ also makes it more consistent with the preceding block.

[drrobotnik]

+1 for explicit type casting. Tested the additional patch, works for me!

[SergeyBiryukov]

In 40039:

Media: In wp_unique_filename(), use explicit type casting when incrementing $number.

This prevents the "non-numeric value encountered" warning in PHP 7.1, caused by trying to increment an empty string on the first loop iteration.

Props drrobotnik for initial patch.
Fixes #39774.

[SergeyBiryukov]

Reopening for 4.7.3 consideration.

[kirasong]

I like the idea of fixing this in 4.7.3. Patch/commit looks good.

[SergeyBiryukov]

In 40075:

Media: In wp_unique_filename(), use explicit type casting when incrementing $number.

This prevents the "non-numeric value encountered" warning in PHP 7.1, caused by trying to increment an empty string on the first loop iteration.

Props drrobotnik for initial patch.
Merges [40039] to the 4.7 branch.
Fixes #39774.