Site fails to load under php 8.x

[Dark Helmet]

Hi folks, I'm currently running XF 2.2.1.2 on php 7.4.33, but figured that php 8 or 8.1 would be stable enough by this point that I could make the switch. However, the instant that I do so and reload my site, I'm greeted with a blank, white page. Reverting to 7.4 corrects the issue. So far as I'm aware XF is firmly compatible with php 8 at this point, what can I do to troubleshoot this? If you need any further particular information, just let me know.

 

[rdn]

Download requirements test script and run it on your server.
Just don't choose PHP 8.2.
8.0 is recommended.

 

[Paul B]

XF works fine with 8.0 - we use it for our Cloud subscriptions.

Some are running 8.1 but it has not yet been approved for use with XF.

Ensure any third party add-ons are compatible with 8.x.

 

[Joe Link]

I seem to run into this issue whenever I switch PHP versions. Rebuilding the master data from the CLI usually fixes it for me (no idea why).

Within the XF root directory, run php cmd.php xf:rebuild-master-data.

 

[Dark Helmet]

Download requirements test script and run it on your server.
Just don't choose PHP 8.2.
8.0 is recommended.

Thank you, I did so and everything checked out. I assumed it would, since I've been using XF for years.

XF works fine with 8.0 - we use it for our Cloud subscriptions.

Some are running 8.1 but it has not yet been approved for use with XF.

Ensure any third party add-ons are compatible with 8.x.

I will stick to 8.0 then, thank you. According to documentation, all add-ons are indeed compatible.

I seem to run into this issue whenever I switch PHP versions. Rebuilding the master data from the CLI usually fixes it for me (no idea why).

Within the XF root directory, run php cmd.php xf:rebuild-master-data.

I'm not sure my host loves me enough to give me CL access, but I'll ask pretty-please and try this. Thanks!

 

[rdn]

Or try to visit the web rebuild, hoping it will work:

https://xf.com/install/index.php?upgrade/rebuild

 

[Rhody]

8.0.x works fine on my sites, but not 8.1.x
I believe the reason is because I am using CloudLinux, or at that was the reason given last year. I'll have to try it again, some time

 

[K a M a L]

I run PHP 8.1 without issues

 

[Dark Helmet]

Or try to visit the web rebuild, hoping it will work:

https://xf.com/install/index.php?upgrade/rebuild

All righty, any particular danger in running the rebuild script, or just let it rip?

 

[rdn]

There is no danger running it.

 

[VBX Co]

8.1 with no issues here.

 

[Dark Helmet]

I did as much prep work as I could, including cleaning up the database and using just the stock theme. Still got the "White Screen of Death" so I ran the "upgrade/rebuild" script from URL as kindly suggested by @rdn. It appeared to start to run, but quickly threw two errors:

Fatal error: Uncaught Error: Call to undefined function Symfony\Polyfill\Mbstring\iconv_substr() in <redacted>/src/vendor/symfony/polyfill-mbstring/Mbstring.php:610 Stack trace: #0 <redacted>/src/vendor/symfony/polyfill-mbstring/bootstrap.php(72): Symfony\Polyfill\Mbstring\Mbstring::mb_substr('Error', 0, 75, 'UTF-8') #1 <redacted>/src/vendor/dokuwiki/utf8/utf8.php(164): mb_substr('Error', 0, 75) #2 <redacted>/src/XF/Error.php(139): utf8_substr('Error', 0, 75) #3 <redacted>/src/XF/App.php(2494): XF\Error->logException(Object(Error), true, '') #4 <redacted>/src/XF.php(202): XF\App->logException(Object(Error), true) #5 [internal function]: XF::handleException(Object(Error)) #6 {main} thrown in <redacted>/src/vendor/symfony/polyfill-mbstring/Mbstring.php on line 610

Fatal error: Uncaught Error: Call to undefined function Symfony\Polyfill\Mbstring\iconv_substr() in <redacted>/src/vendor/symfony/polyfill-mbstring/Mbstring.php:610 Stack trace: #0 <redacted>/src/vendor/symfony/polyfill-mbstring/bootstrap.php(72): Symfony\Polyfill\Mbstring\Mbstring::mb_substr('ErrorException', 0, 75, 'UTF-8') #1 <redacted>/src/vendor/dokuwiki/utf8/utf8.php(164): mb_substr('ErrorException', 0, 75) #2 <redacted>/src/XF/Error.php(139): utf8_substr('ErrorException', 0, 75) #3 <redacted>/src/XF/App.php(2494): XF\Error->logException(Object(ErrorException), true, '') #4 <redacted>/src/XF.php(242): XF\App->logException(Object(ErrorException), true) #5 [internal function]: XF::handleFatalError() #6 {main} thrown in <redacted>/src/vendor/symfony/polyfill-mbstring/Mbstring.php on line 610

I'm not experienced enough in the code to parse all that, but from what I can see it does reference 'vendors' 'symfony' and 'dokuwiki'. However, I don't have any add-ons from such vendors. Don't know if that's part of the stock XF code, or something else. Any thoughts?

 

[Paul B]

Enable iconv in PHP.

 

[Dark Helmet]

Enable iconv in PHP.

That appears to have been the root of the issue. When the host made PHP 8 available, they apparently didn't install several packages, including iconv, GD and cURL. Once iconv was enabled the site would load, and from the control panel diagnostics I could then see that the other two were needed. Site is running noticeably faster now. Thanks, @Brogan!

 

[ckelley]

My hosting provider upgraded PHP to 8.1 and I get a blank site now like the OP.

I rolled back to 8.0 hoping that would fix it, but I get same blank page.

I ran the test script and it comes back compatible. What am I missing?

I've been running this site since 2017.

 

[TPerry]

Frequently you will get a notification when viewing the site source.
Can you provide a link to your site for others to check?
From what it looks like, you don't have the mySQL PECL installed for PHP.

 

[Mark87]

running 2.2.13 and having the same issue running 8.0 as above, I have tried some things mentioned here but cannot resolve it.

 

[Suzanne O]

I think mine's 8.1

 

[Mark87]

My host has helped me get this sorted, running 8.1 without any issues.

 

[CedricV]

We have been running 8.2 for a while now, no errors except some add on we had to patch manually.