phpBB: Unable to add attachments to posts with PHP 8 or higher.

[wmttest]

Hi there,

I've found I'm unable to add attachments to posts with PHP 8 or higher on Altervista, even though this issue doesn't occur on my personal website which uses a paid host.

If I use PHP 7.3, I get a green tick next to attachments after uploading them, but on PHP 8 or higher I get an exclamation icon and the attachments don't appear in the post after I click submit.

I can't see anything in phpBB's error log in the ACP, so perhaps someone could look in the logs for an error at roughly 2:57 PM on Fri Mar 20, 2026?

I did report this some time ago but never got a resolution, however it's more important now that PHP 7.3 is being removed soon.

Best,
Hamish

[alemoppo]

Hello,

Could you please let me know which version of phpBB you are using? I'll try to reproduce your issue on my side.
Have you tried updating phpBB to the latest version? (after a full backup).

Thanks.

Bye!

[wmttest]

Hi there,

I'm using phpBB 3.3.15 (the latest version at the time of writing). It's also a fresh install, but I've also observed this issue on another forum that was originally installed in 2017 and has been upgraded to the latest version.

Best,
Hamish

[alemoppo]

It seems to be a phpBB bug: https://www.phpbb.com/community/viewtopic.php?t=2589106

However, the fixes seem to have already been implemented, but the error still occurs (I was able to reproduce it).

Maybe we should ask on the phpBB forums.

Bye!

[wmttest]

I shall ask and post a reply here with the link.

[wmttest]

I don't think this is the same issue actually, as disabling Javascript (I saw this tip on the phpBB forums) shows that "there is not enough free disk space" rather than the other error in that linked post. I shall now report this on the phpBB forums and see what they suggest, and post a link here.

[wmttest]

Here is the link: https://www.phpbb.com/community/viewtopic.php?t=2670817

[wmttest]

Looks like it might be this actually: https://tracker.phpbb.com/browse/PHPBB-16705

Any way to get the php.ini settings changed to make it compatible?

[alemoppo]

The function disk_free_space() is available on AlterVista, but it returns false.
Because of this, enabling or checking it via php.ini is not useful, since

function_exists('disk_free_space');

already returns true.

If you want to apply a manual workaroud (yes, is not a good way), you can force the check to pass by adding "return true;" at the beginning of the "check_disk_space()":

phpbb/attachment/upload.php line 303

protected function check_disk_space()
{
    return true;
    if (function_exists('disk_free_space'))
...

However, in my case this fix was not enough. I also had to initialize "$exitStatus" in the Symfony file:

/vendor/symfony/http-foundation/File/MimeType/FileBinaryMimeTypeGuesser.php
On line 57

ob_start();
$exitStatus = 1;
passthru('command -v file', $exitStatus);
$binPath = trim(ob_get_clean());

Otherwise, a warning like "Undefined variable $exitStatus" may occur (which may break uploads).

Bye!

[wmttest]

I can confirm this behaviour using a PHP script given to me by a member of the phpBB forums. I must insist you fix it so that disk_free_space() works correctly, as this breaks phpBB for all users on PHP 8 or higher on Altervista. Otherwise I will be moving to a different web host.