Problem/Motivation
When site maintenance mode enabled while page cache module also enabled most visitors continue to get cached pages
Proposed resolution
Add notice to site maintenance form when page cache module enabled pointing to clear cache to show message to all visitors
Remaining tasks
get UX review
commit
User interface changes
message added to admin/config/development/maintenance form
API changes
no
Data model changes
no
Release notes snippet
TBD
Original report
When i recently upgraded Drupal 8.1.8 to 8.1.10, i turned on "Maintenance mode" for the site, but it only worked after i "cleared all caches" in Configuration->Development->Performance menu. I think this is a bit confusing. Maintenance mode should override or clean the cache, because it's important that it works while something is updated.
This ticket may be considered a "feature request", but I believe, drupal does not go into maintenance mode because of this issue, when one does "online module update", ticking the option "Update in maintenance mode".
Proposed solution: Add a note to the Maintenance mode page about this:
Since the page cache is enabled, you must flush the page cache to display your maintenance mode message to site visitor. Visit the performance settings page to flush the page cache.