PHP notice "Undefined index: region" on layout overrides when using the Field Layout module

just reporting that this error still exists -- I'll be upgrading to php 8 and d10 soon, but notice it on an up to date d9/php7 system

"Undefined index: region in Drupal\field_layout\FieldLayoutBuilder->buildForm() (line 109 of "
running 9.5.3 but have not yet updated PHP (still running 7.4.3).

9.5.4, patch still won't apply. Manually changing the lines in FieldLayoutBuilder.php to reflect the patch works.

#30 worked for me on 9.5.9

The patch did not apply for me. But manually changing the lines did work. 9.4.15

@jive01 what you are looking for is

"drupal/core": {
  "patched field layoutbuilder issue": "https://www.drupal.org/files/issues/2019-12-16/undefined_index_region_field_layout-3053906-30.patch"
}

Don't currently use this module but this was broken by 🐛 Field layouts doesn't seem to work for embedded forms Fixed so needs a reroll by someone that can test it.

The patch does not apply, but if you manually make the changes the solution works - on D10.1.

Maybe we should close the case earlier than 11.x

11.x is a placeholder. All changes are made in that branch first and then backported to 10.1 or 10.2 or whatever.

Also there's a merge request now, the patch doesn't need to be used.
If you need one, you can append .diff to the merge request URL, like https://git.drupalcode.org/project/drupal/-/merge_requests/4390.diff

Only, don't use .diff directly your composer projects because you don't know what version of the patch you're going to get and theoretically could get unsafe, untested, or broken code since the diff moves and issue forks are open.

This issue is going to have to land at some point.

We have two core(!) modules that haven't been able to be enabled at the same time out of the box for the past 4 years, I see that as a big issue.
The patch only changes two lines, I think it's safe to have this committed?

Also yes, don't use .diff links from MRs in your composer patches. Download the diff contents to a local patch file, and add that as a patch.

Is this just being held up by a missing test?

It's an issue where a field display config may not have the 'region' key set. This is expected as a region key is not guaranteed as stated in #3053906-25: PHP notice "Undefined index: region" on layout overrides when using the Field Layout module → . The buildView and buildForm functions should be checking to see if the key exists before using it which with the patch, they are now doing.

What is the test here?

Is it just setting up the state as described in the issue which current fails with a php warning/error, and then just visiting the page to ensure it now works with the patch in place?

Just rerolled #30 for 10.1.x

#63 works on Drupal 10.1, confirmed

This patch rerolled for D10.2.10.