Doubloon on node type human names

Interesting, I didn't even know we enforced this in Drupal 7 as well.

This should have a test to ensure adding and updating works as expected.

Patch "doubloon-on-node-type-human-names-2396141-3.patch" does display the error message for unique machine-readable name and not for human-readable name. However, when user tries to enter an unique name on the same page and save the field, the error message does not disappear. So, this patch fails. Attaching screenshot.

Same problem arises with "doubloon_on_node_type-2396141-5.patch".
A new unique entry is not allowed on the same page once the error is displayed for duplicate machine_readable name. However, an error message for duplicate human_readable name is displayed if the user enters another duplicate name on the error page. Attaching screenshots.
Changing it to Needs work as user should be allowed to add a valid unique entry on the same page.

I am going to work on trying to improve the test coverage to indicate that the expected behaviour is not happening.

The issue was that the check for a unique human readable name was case sensitive.

I'm uploading a test only patch, a patch with the fix and an interdiff.

I agree with @vaplas that this is not a bug and we should not add this check.

Once a node type is created, its machine name is set in stone and cannot be changed because Drupal internals depend on it. The human-readable name, on the other hand, can be modified freely at any time. So if an administrator creates two types with the same name by mistake, this can be instantly fixed.

Repeated node type names do not have any negative effect on the site but disallowing them will limit possible usecases, like the one @vaplas described.

I will close this issue, please reopen it if you feel that this feature will be advantageous.