Using the layout builder discard changes button should ignore any input and skip validation

Good catch, let's get some test coverage first.

+++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
@@ -0,0 +1,107 @@
+    $urlParameters = ['entity_test' => $entity->id()];
+    $url = Url::fromRoute('layout_builder.overrides.entity_test.view', $urlParameters);

Big nit: we don't need the $urlParameters var anymore as it's only used once.

Other than that, can't fault it!

Nice! Sending to RTBC

This looks great, just a couple of observations that may or may not be relevant

1. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
   @@ -0,0 +1,106 @@
   +    EntityFormMode::create([
   ...
   +    $displayRepository->getFormDisplay($entityTypeId, $bundle, $formMode)
   

   we create the form mode and have it in context, but we re-load it back from the repository and save it again - can we set the component before the first save call and avoid the second save as well as the repository load?

2. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
   @@ -0,0 +1,106 @@
   +    $session->addressEquals('/entity_test/1/layout/discard-changes');
   

   Should we also test that we can submit the discard changes form once we arrive here?

You are right that those are two objects. But by using the display repository, there's still a double save.

Adjusting the test to fit with other LB test conventions. These are only stylistic changes.

I have time and can test this today.

Following the steps in the description I was able to verify the error
Using patch #15 resolved the issue

The patch for 9.1 and 10 are both failing tests, setting back to NW.

The 9.1.x failures seem unrelated (and outdated?), I couldn't reproduce the 10.x failure locally even with assertions turned on but probably something with my setup. Comparing to other similar test setups, I think it may be to do with full vs default mode.

Fixed the assertion error by setting a label on the test entity.

• I've read the comments and all feedback appears to be addressed.
• Test looks good to me and is passing.
• No material changes to functionality of patch since it was manually tested by @smustgrave
• IS looks complete (assuming [empty] means "none")
• Can't see any core gates we've missed

LGTM, kicking off test for 9.4 but not 10.x because HEAD isn't passing right now.

Queued 10.0.x as HEAD should be fixed now #3298821: Remove test that tests drupal/core-composer-scaffold when it is not allowed is in

Committed and pushed db43eba838 to 10.1.x and 668e3a781a to 10.0.x and b84170c86a to 9.5.x and e5c94094be to 9.4.x. Thanks!

Backported to 9.4.x as a non-disruptive bug-fix.

This caused a regression on D10 because classy is deprecated there. There's no need for the test to use classy so I changed the default theme.

commit e1b4aafae9c2cedd9443ed9ab591e0f5d01b0a75 (HEAD -> 10.1.x, origin/10.1.x)
Author: Alex Pott <alex.a.pott@googlemail.com>
Date:   Thu Oct 6 16:25:32 2022 +0100

    Issue #3165010 follow-up: Using the layout builder discard changes button should ignore any input and skip validation

diff --git a/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
index 24d28c3839..8ced12daea 100644
--- a/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
+++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderFormModeTest.php
@@ -29,7 +29,7 @@ class LayoutBuilderFormModeTest extends BrowserTestBase {
   /**
    * {@inheritdoc}
    */
-  protected $defaultTheme = 'classy';
+  protected $defaultTheme = 'stark';

   /**
    * {@inheritdoc}

I ensured that the test still fails without the fix with stark as the default theme.