On September 5th, 2023, we are releasing new versions of our software with Joomla! 5 support. Due to the number of changes, there are common release notes across these versions, detailed in this article.
Joomla! 5 support
Two weeks ago Joomla! released the first public beta of the upcoming Joomla! 5 major version.
Due to the number of changes between this and the previous alpha versions, our previous versions did not work on Joomla! 5 Pizza, Bugs & Fun — August 2023.
We put our head down and worked through all those changes, addressing them, and making sure that our software will now work correctly on Joomla! 5 — at least, as it is in its current state. We, therefore, add official but tentative support for Joomla! 5 in the new releases.
Based on past experience, we expect more backwards incompatible changes to make their way into Joomla! 5 during the next few weeks up to and including the first stable Joomla! 5.0 release. We will keep monitoring them and addressing them.
As always, we do not recommend switching any production site to Joomla! 5.0 until 2–3 weeks after the first stable version of Joomla! 5.
We have changed the PHP namespaces of our extensions to match the (as yet undocumented) intention of Joomla!'s core maintainers about third party extensions' PHP namespaces.
The namespaces in all of our extensions now start with our company name, i.e.
Akeeba\. In the past this was indeed the case for our components, but our plugins and modules had the generic prefix
Joomla\ due to an unfortunate misunderstanding of how the new at the time (and still officially undocumented) Joomla 4 MVC was meant to work back in late 2020, when we started migrating our extensions.
This one-time change has some implications on whether Joomla! will be able to find and load the code with the updated namespace. If it cannot, it will display (usually briefly) an error message stating “class not found”, “missing class”, or something similar to that. This is the result of how Joomla! works, and your server's configuration. Here are the two key points which can cause problems:
- Joomla! caches the namespaces of core and third party extensions in the
autoload_psr4.phpfile in its cache directory, generally a welcome performance-enhancing behaviour. Whenever you install an extension update, or a core Joomla! update, Joomla! tries to delete and create this file afresh.
- Servers with PHP OPcache enabled will not “see” that
.phpfiles have changed during the caching period set up in PHP's configuration. To work around that limitation, Joomla! asks PHP to clear the OPcache for each
.phpfile it writes to disk during the course of an extension or core Joomla! update.
While Joomla! generally works well, we observed a few issues which do get in the way:
- If the
autoload_psr4.phpis unwriteable Joomla fails to renew this file silently. As a result, it misleads the user into believing that an extension is misbehaving when, in fact, it's a Joomla! failure to check if this file is writeable (therefore can be updated, therefore can be trusted) before using it.
autoload_psr4.phpmay not be created afresh if an update fails, but has already written files on disk. This creates a discrepancy between the code available on your server and what Joomla! has cached about this code in that file, breaking your site.
- The code which resets the OPcache is incomplete due to an esoteric quirk of PHP. PHP will only reset the OPcache for a file if it can detect that the file has changed. However, PHP caches the filesystem information of files it has already loaded which, in Joomla's case, includes the all-important
provider.phpfile of every extension using the modern Joomla! 4 MVC. The undocumented workaround for this behaviour is to use PHP's
clearstatcache()to tell it to check the disk again before calling the code to reset the OPcache for a file.
Our extensions include post-installation code designed to mitigate these issues to the extent humanly possible:
- We delete the
autoload_psr4.phpfile and ask Joomla! to create it afresh. Then, we reset its PHP filesystem stats cache and the PHP OPcache on that file, just like what Joomla! does during a core Joomla! update.
- We have included code which goes through all the
.phpfiles in our extensions and resets PHP's OPcache for them, exactly like what Joomla! does during a core Joomla! update. This is more comprehensive that Joomla's code currently used in its
Despite our best efforts, we understand that some far less common server configurations may make it impossible for the mitigations to work. Namely, we have identified the following cases, mitigations, and expected impact:
- If the
autoload_psr4.phpfile and / or its containing folder is not writeable to PHP itself the file will be impossible to delete. As a result, Joomla! will keep using the old, out-of-date file, breaking your site. Note that most affected sites would already have issues installing or updating Joomla! and third party extensions. Mitigation: You will need to delete that file (
administrator/cache/autoload_psr4.php) yourself. Expected impact: rare; less than 0.1% of sites.
- Some servers may have disabled the PHP features necessary to reset the OPcache on specific
.phpfiles. Mitigation: You will have to either wait until the OPcache expires (usually between a few seconds to a few hours), or ask your host for help on resetting the OPcache. Expected impact: very rare; less than 0.01% of sites.
- Some web hosts may be using a server cluster, i.e. multiple servers which handle requests in a round-robin, or availability basis. As a result, the OPcache will not be reset across all servers in the cluster, causing intermittent errors on your site. Affected sites will already have problems installing or updating Joomla! and third party extensions. It is furthermore extremely unlikely that someone is hosted on a server cluster without being acutely aware of the fact, and what is necessary. Mitigation: ask your host to reset OPcache across all servers in the cluster. Expected impact: infinitesimal; less than 0.001% of sites.
TL;DR: What to do if something breaks
Despite us taking all reasonable precautions to refrain from inadvertently breaking your sites, some rather rare server configurations might get in the way of a stark minority of our clients. If your site stops responding, at all or intermittently, with an error indicating “class not found” please do the following:
- Wait a minute, then reload the page. More often than not, that's all that's needed.
- Delete the
administrator/cache/autoload_psr4.phpfile, and reload the page.
- Ask your host to reset the OPcache, or similar code cache, on your site's server(s).
We would like to state that the likelihood of these issues occurring is vanishingly small. The vast majority of our clients will NOT experience any of that. We include this statement with our software because we believe in transparency, and are proponents of the “forewarned is forearmed” mantra.