Scheduling fails with Drupal page cache and cache.page.max_age set to 0

@swirt are you using any other caching layer like redis, varnish, or memcache?

We are using memcache.

@swirt, Does this issue also occur when you disable memcache? This could be tested on your non-production staging or development environments.

I am curious if memcahe has a similar issue to the one redis had. The one documented in the project's README and needs a patch to resolve.

This issue affects a clean Drupal installation without memcache or redis - I was able to replicate the issue using a DrupalPod gitpod instance.

The issue should ideally be fixed upstream, but it's quite a big change in core's behaviour (especially with the number of failing tests), so I've opted to simply invalidate page caching within the module instead.

If someone could test #17 we can include in 3.0.x branch.

Going to include in next release.

Automatically closed - issue fixed for 2 weeks with no activity.

One of the changes from the issue: https://www.drupal.org/project/sitewide_alert/issues/3476702 🐛 The Sidewide Alerts load route set a maximum cache max age of 30 in an interesting spot Active , the commit: https://git.drupalcode.org/project/sitewide_alert/-/commit/2f7737f345815..., removed line:
->setCacheMaxAge(30)
from the CacheableMetadata object.

It was assumed that the code:

if ($expireDate = $this->sitewideAlertManager->nextScheduledChange()) {
  $response->setExpires($expireDate->getPhpDateTime());
}

which sets expiration on the response is enough, but as a consequence of the problems expalined in this ticket and other tickets like:
- https://www.drupal.org/project/drupal/issues/2835068 🐛 PageCache caching uncacheable responses (violating HTTP/1.0 spec) + D8 intentionally disabling HTTP/1.0 proxies = WTF Needs work
- https://www.drupal.org/project/drupal/issues/2352009 🐛 [pp-3] Bubbling of elements' max-age to the page's headers and the page cache Postponed
the cache is not properly broken (released) here as the expiration is not counted in for the Drupal Cache in this special case.

I'm experiencing this probelm even thoug the cache.page.max_age is NOT equal 0, so as a good engou workaround for now, reverting the problematic commit is helping to my problem and maybe others will appreciate it as well.

I'm seeing the exact same issue as @dabbor documents above. I've taken out 🐛 Scheduling fails with Drupal Page cache Active to continue discussion and address it.