Maintain backward compatibility with an abstraction file

In a few of the previous posts in the 1.5 plugin update series, I’ve talked about maintaining backward compatibility with earlier versions of BP while upgrading your plugins for BP 1.5. In those posts, I suggest the function_exists() method, which will always work nicely.

However, there's another method you might want to consider: update your plugin as if you weren't going to support earlier versions of BP, and then conditionally include an abstraction file that defines the necessary functions. Here's what I mean.

When I was upgrading BuddyPress Group Email Subscription for BP 1.5, I wanted to make use of a few BP 1.5-only functions: namely, bp_is_groups_component() and bp_is_group(). So I did. Then, I created a new file called 1.5-abstraction.php, which looks like this. You'll notice that I haven't copied the functions directly over from the 1.5 source. The main reason for this (especially in the case of bp_is_groups_component()) is that the original function references bp_is_current_component(), which in turn has a bunch of complicated logic that is not necessary in my case. So, in my case, it made sense to take a minute to write less general functions from scratch. However, I could just as easily have copied these two functions directly into my abstraction file.

Then, I loaded the 1.5-abstraction.php file conditionally, like so:

if ( defined( 'BP_VERSION' ) && version_compare( BP_VERSION, '1.5-beta-1', '<' ) ) {
	require_once( dirname( __FILE__ ) . '/1.5-abstraction.php' );
}

In this way, I only load the file when necessary.

The nice thing about this method is that my main codebase remains clean and easy to read. When I decide to drop backward compatibility for early versions of BP, this file can simply be removed from the package.

Another great thing about these abstraction files is that we can share them. Feel free to copy the small one from BP Group Email Subscritpion into your own plugin and build upon it - and share your own version with other developers.