[wp-hackers] Idea: Plugin Version Limitation

[Austin Matzko]

On Mon, Jun 16, 2008 at 9:55 AM, Otto <otto at ottodestruct.com> wrote:
> Firefox has a system where, when you upgrade, addon's that are not
> tagged as being compatible with the new version are automatically
> deactivated. This prevents incompatible plugins from horking things
> up. It is not without flaws, but in general it works very well.
>
> WordPress could introduce a new plugin field, "max version" or
> something similar, where a plugin can specify this as well. It could
> then keep incompatible plugins from being activated on upgrades.

It seems likely that this would cause more problems than it would solve:

* It breaks private or custom plugins.  Firefox lets extension authors
specify an update URL specific to that extension, so that updates can
be downloaded from a custom location.  WordPress has the wordpress.org
API hard-coded into the code.  So WordPress setups using custom
plugins would 1) never notify their users of updates 2) would
consequently lose their functionality upon upgrades.

This is not a trivial problem: I try to write plugins for clients with
a large degree of forwards-compatibility, and although I can't
guarantee that all future versions of WordPress will be supported, for
the most part they have been.  The max version proposal would mean
that someone would have to increment the max version for every custom
plugin, even ones that work fine; this means greater expense for
businesses and more time wasted for owners of self-hosted blogs.

* The risk of upgrades causing significant problems is low.
1) Most of the time using the WordPress API keeps you from
encountering problems.  I frequently use plugins that haven't been
updated since WP 2.0, and on a few sites I'm still running some from
1.5 with no problems.  The exceptions are unusual, such as the change
in 2.3 in the taxonomy.
2) Matt Mullenweg stated recently that WordPress upgrades will no
longer involve significant stepwise changes, for this very reason of
not breaking setups.

* There are possible better ways:
1) The (future) automatic WP upgrade could simply warn users about
wordpress.org plugins that have a "Tested up to:" version that is too
low, and let them decide if they want to disable them.
2) Or the automatic WP upgrade could de-activate all plugins, then
re-activate them in turn and catch fatal errors.  This would have the
advantage of testing functionality rather than version numbers.