Make expiryDate bust cache

[jsunsawyer]

Just ran into this issue when refactoring an old Craft 2 site.

Basically, our client uses news posts to post specials that show up on the homepage. When they're no longer relevant, they need to no longer display on the homepage and go to archived posts.

expiryDate doesn't bust cache tags and I couldn't figure out a very elegant solution. Ended up simply setting cache tags to expire daily in these sections. Cache busting in instances like this seems like something that should just be built in.

I couldn't find anything on this functionality changing for Craft 3, but maybe I missed something.

[Anubarak]

Why isn't this a solution for you https://docs.craftcms.com/v2/templating/cache.html#until

[jsunsawyer]

I'm not dealing with a single entry. It's a general list of featured entries on the homepage, that can expire. I'd have to do something like loop through my entries to find the next expiry date if one exists, then set a couple different cache settings depending on whether any of the active posts have expiry dates.

It just seems like this built in field should notify the template that it has changed so the cache is automatically cleared. Just like on a save of an active entry or when publishing a new entry.

[brandonkelly]

Related: #978

[brandonkelly]

Added smart cache busting based on entry expiry dates, for Craft 4.3 (#11901) 🎉

[brandonkelly]

Craft 4.3 was released earlier this week with this change!