Error installing library Topic is solved

[jjbongio]

I recently converted from Joomla 3.10 to Joomla 4.2.6

When I install a library, I always get the error
Cannot declare class XXXXInstallerScript because the name is already in use

Screen shot attached.

joomla.jpg

Clearing all caches always fixes it

[jjbongio]

Update. The odd thing is that if I clear all caches before doing the install, it fails with the error above. When I then clear caches and reinstall, it works.

[jjbongio]

The zip installs without problems on Joomla 3.10.11

[toivo]

Which particular library is it? Are you sure it is compatible with Joomla 4?

[jjbongio]

It's my own library, and it runs fine under Joomla 4 once it's installed. The only problem I see is the install problem referenced here.

[Per Yngve Berg]

Mod. Note: Relocated the topic to the Coding Forum.

[ceford]

Looks like you are using a custom installer script that does all the work usually done from index.php. Joomla 3 and 4 install.php scripts look quite different, like this:

Code: Select all

\defined('_JEXEC') or die('Restricted access');

use Joomla\CMS\Component\ComponentHelper;
use Joomla\CMS\Factory;
[or various other classes needed for installation]

class com_fooInstallerScript
{

}

Where the class contains various functions called by the installer (the Joomla one). I don't know how you might fix the problem! If the library gets installed and works it may be best to leave it alone.

[jjbongio]

Thanks. Do you have a pointer to the differences in installer scripts between J3 and J4?
My script is quite simple. I want to display a message with the component version and to delete obsolete files. All of that does work after I clear the cache, so it's not a huge deal.

[ceford]

I can't really help, other than point you to libraries/src/Installer/InstallerAdapter.php line 961 where you are loading a file containing a class name that is already loaded. You probably know that. Look at the script files in some of the administrator components - mostly you only need preflight and postflight. What does your script file do?

[jjbongio]

Thanks, I'll look there. It just displays the installed version and deletes obsolete files.

[jjbongio]

Good suggestion to look at other components.

Poking around components, I found nothing unusual, but I did find something looking at library install scripts. Few libraries that I use have them, but Regular Labs does. And they wrap their class with a check to see that the class isn't already defined. When I did the same thing, the problem went away, and it seemed to run the install script correctly.

I'm guessing that there's something in library install where the script can get loaded twice, but I'm not going to debug it.

Thanks for the help.