Use require_ and include_once instead in wp-settings.php

[rob1n]

Use require_once and include_once instead of require and include in wp-settings.php. What this will accomplish is minimize the chance of files getting included twice, however likely.

Ryan, however, when I brought up this idea on IRC, mentioned that the _once functions was slower than its cousins. Might be good if we could profile this.

There is no need to profile. require_once() and include_once() are slower than require() and include() up to PHP version either 5.1.x or 5.2.x. Since you support PHP 4.2, you'll being slowing WordPress down for what might be a majority of your users.

Also, I haven't yet had any problems with what you describe. Do you witness any plugins that require certain wp-includes files? I would just assume that unless someone else messed up that the files wouldn't need to use require.

It should be assumed that wp-settings sets up and includes the files in wp-includes and no one else should do so.

Premature optimization.

Won't fix?

Premature optimization and if there are any problems, then it is the problem of another script.