[geeklog-devel] Autoinstall plugins and dependencies

[Randy Kolenko]

The autoinstall for plugins is a great way to eliminate the manual
install process and to facilitate the upload of plugins.
However there are some functional aspects of the autoinstall process
which need to be addressed.  In particular the idea of plugins which
have dependencies on other plugins.

For example, if Plugin A depends on Plugin B being installed, there is
no way with the autoinstaller to notify the end user that their plugin A
needs to have Plugin B installed first.  

We need to have a change to the plugin install routine to have a
preliminary installation check done first so that the plugin being
installed has the chance to check for dependencies, and return friendly
error messages.

This augmentation needs to behave with the fresh/clean installation of
geeklog as well in the event plugins are bundled with a distribution.
That means that a prerequisite test should not disrupt the clean
installation of plugins during a fresh install and should gracefully not
install themselves.

I suggest having a plugin_autoinstall_prerequisite_pluginname function
in the autoinstall.php file that would carry out the dependency checks
and return status/message codes.  On a geeklog fresh install, those
status/error codes can be dumped to the error log, and on manual
installs, they can be displayed as error messages in the plugin admin
page.

Thoughts?

-randy