Enhanced error templates

[timkelty]

If the app hasn't customized the plain text responses for, eg "Internal Server Error", Cloud could serve a nicer default.

[jamesmacwhite]

I've also thought about this, but at a certain point, if Craft is failing to bootstrap, it wouldn't be able to serve any nice error template set in a project, because it's happened before those could be loaded, so it would have to come from Craft Cloud.

In that scenario it would be the Yii error handler with the $defaultMessage which is "An internal server error occurred". Can this be customised in a Craft CMS app project wide? I'd imagine it is limited to the plain text message, given the level it occurs at?

[timkelty]

I was even thinking more catastrophic – like a fatal PHP error. So, we could have a place in Craft Console where you could upload a full HTML doc for a given error.

That would be easy enough, but maintaining those static templates is always a pain.
What could even be cooler:

• On build/deploy, Craft finds any project-defined error templates (e.g. _errors/500.twig)
• The builder makes an HTTP request, gets the rendered HTML, and stores it.
• Before the gateway returns a non-Craft error page, it first checks to see if it has an error page cached for that given status. If it does, it serves that instead.