At the moment setting the current scene (or screen) is delayed until the next event loop, after everything has been handled. It would be useful if changing scenes was possible, but not sure if this should be considered a bug or current design limitation.

Is there any way to have a script wait until the next event loop, or to force one to occur?

Tom: one of the next todos for Py API is to make scripts proper part of our event handling system, or with timers, or to attach to redraws. It's a known issue and will be resolved asap.

Hello. No idea if this'll be heard, but I've been looking around for an answer and not getting anywhere.

I'm basically trying to do the same thing as Tom was - setting a scene, but bpy.context.scene doesn't update immediately. Is there a known way now to force another event loop or wait or something? Something to make bpy.context.scene update immediately?

Wow, a bug report from seven years ago! Since then I've discovered how to wait for the next event loop:

import bpy

def scene_update(scene):
	print(scene.name)
	bpy.app.handlers.scene_update_post.remove(scene_update)

def hook_scene_update(callback):
	bpy.app.handlers.scene_update_post.append(callback)
	
hook_scene_update(scene_update)
bpy.context.screen.scene = bpy.data.scenes[1]

Hmm, I don't think that'll work for my purposes - I'm doing something in a function that needs to execute immediately, so I dunno if I can wait over the course of a script execution...

Thanks for the answer, though! I'll see if I can make any headway. I'll let this stay dead, haha.