'node' variable in page.html.twig is not available on preview node page

Tagging this with Field UX even though this is not directly related to Field UI because this is still related to the user flow of configuring a content type.

Confirmed the issue on Umani demo.
Patch fixes the issue

Added screenshots to issue summary to show before/after

+1 RTBC

Discussed with @laurii in slack the idea of adding a check of \Drupal::routeMatch()->getParameter('node_revision') to ensure revision pages also get the node object, but it seems the node_revision parameter is always accompanied by the node parameter. Ultimately decided checks for node and node_preview cover all use cases.

I think we should be trying to deprecate this rather than using it more widely. Why is it happening in template_preprocess_page() and not node_preprocess_page(), and/or why isn't it generic for entity types - if it's really needed at all. Having said that, maybe we want to commit this and look at it more widely in a different issue.

+1 for looking into deprecating the node variable in a follow-up. FWIW, this is not adding additional usages, it just fixes the current, somewhat broken behavior. This also addresses usability impacting bug in Umami.

I think removing node could be disruptive to many sites, even if core doesn't use it heavily. However, I think a followup to discuss that should be created, and once that exists I'd be inclined to commit this 🙂

Opened follow-up for #6: 🐛 template_preprocess_page has a soft dependency on node module Active .

Committed to 10.1.x, cherry-picked to 10.0.x. Will backport this non-disruptive fix to 9.5.x after confirming tests pass on that version.

Cherry picked to 9.5.x as well.

Commit to 9.5.x is missing:
https://git.drupalcode.org/project/drupal/-/commits/9.5.x?search=Issue+%...

Thanks @luenemann, looks like the push didn't take. This is up now.

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

Published change record.