All caches should be cleared after config sync

[jenlampton]

Describe your issue or idea

After a config sync, so many things could have been changed that would require a cache clear, that we should always clear the caches. Even though the code does seem to call backdrop_flush_all_caches() the menu router cache, in particular, is not cleared.

Steps to reproduce (if reporting a bug)

• Copy all config from active to staging
• Delete the home page layout.
• Confirm the home page 404s at home
• Do a config sync to reinstate the home page
• attempt to visit the home page path, home

Actual behavior (if reporting a bug)

• 404

Expected behavior (if reporting a bug)

• new page should be accessible immediately

To confirm it's a cache clearing problem...

• Clear all the caches via the link in admin menu
• attempt to visit the new path testing again
• confirm the new layout can be seen

[herbdool]

backdrop_flush_all_caches() calls menu_rebuild() which calls menu_cache_clear_all() so at first blush looks like it would clear all the menu router cache already. So maybe the cache clearing isn't working as it should after the config sync?

[jenlampton]

Know what I just thought of... this layout also needs a layout menu router item!
I bet the initial import doesn't have one, but then there's some kind of fancy self-correction that adds one so the second time I clear the cache it's there.

[jenlampton]

I've updated the steps to reproduce to target config sync specifically. I'm still facing this problem so looking into it again.