Path field does not respect settings in form display

Just ran into this issue myself and made a small patch.
I looked at the node module and saw it was doing an isset($form['uid']) there, so I applied the same style of logic in the path module's form alter. It now only adds the details-fieldset if the field already exists in the form.

I've written a test that, with a bit of help from chx. :)

It first asserts if the details-tag id and the field exist. Then removes the path alias field from the form display and checks again if they are gone.

great work spadXIII, no problem this one.

The test does not fail when the changes to core/modules/path/path.module are not applied.

Also added the test in a separate file for easier testing.

Thanks @SpadXIII for proving me wrong!

So thinking about this issue has led me to file #2378947: Hiding a field using form modes should not remove it from the form object - we should just be setting #access to whatever the path field has here (once that lands)

+++ b/core/modules/path/src/Tests/PathNodeFormTest.php
@@ -0,0 +1,54 @@
+ * Contains \Drupal\path\Tests\PathAdminTest.

Lol so this is why I thought the test passed with the patch... I copy and paste this to run the test from the command line... and here we have a copy and paste error!

Indeed a copy-paste error. Next to that, if a field is not removed from the form object but access-false, my patch won't fix anything. Will update tonight!

Changed the module to account for the #access false, by doing an !empty() check.
Also fixed the file-comment :)

*note to self* don't forget to change status to needs review when adding new patches....

+++ b/core/modules/path/path.module
@@ -42,7 +42,7 @@ function path_help($route_name, RouteMatchInterface $route_match) {
+  if ($node->hasField('path') && $node->get('path')->access('edit') && !empty($form['path']['#access'])) {

Actually this condition should be done with a #access too... ie. $form['path_settings']['#access'] = $node->hasField('path') && $node->get('path')->access('edit') && !empty($form['path']['#access']);

This means that your element can be altered by any other module without having to check it is there.

I think I understood what you were saying, changed that in the patch. The fieldset is always added in the $form, with the if-statement for the #access.
I also changed the order of the checks; the cheaper empty-check first.

The test is unchanged.

Looks good. Please post an interdiff next time.

Regardless of what happens in #2378947: Hiding a field using form modes should not remove it from the form object this looks good. This issue is a normal bug fix, and doesn't include any disruptive changes, so it is allowed per https://www.drupal.org/core/beta-changes. Committed 821a9ce and pushed to 8.0.x. Thanks!