add a pre_template_include filter, so as to allow caching of the template file

[Denis-de-Bernardy]

rather than running file exists all over the place in the template loader, we should offer the possibility for a plugin to cache the information for use in subsequent pages.

[nacin]

Patch looks fine, though I'm wondering why you didn't place it above 404 as well, just cause.

More so, couldn't you write to cache on the template_include hook and pull from cache on template_redirect?

Seems like a worksforme, considering that the two hooks now seem more than flexible enough for what you're going for.

[Denis-de-Bernardy]

re 404, the point would be to write a plugin that looks up the available template files, caches that accordingly, and knows, based on what the WP Query tells it, what file to use without needing to do a file_exists() call.

template_redirect works fine too for this, up to a point:

• it would mean the plugin needs to handle robots, feeds, etc. it would also mean the plugin would need to manage whatever we add in there in the future.
• it would re-introduce the inflexibility that led us to introduce the 2nd hook in the first place, i.e. the plugin itself would not be plugin-able.

[hakre]

Additionally, and that is not that visible in the trac patch browser, pre_template_include is building a good pair to template_include, a principle that you can find more and more often within the codebase.

[nacin]

Apparently I had misread the diff, and thought 404 was processed before the filter. Obviously, filter comes first in the diff.

[pbearne]

the template loader code has been refactored so that this filter no longer makes sense

Closing as won't fix