[5.3] Revert #44161

[bembelimen]

Summary of Changes

With #44161 the limitation that custom fields has to be unique system wide was removed. This could break when e.g. a plugin loads custom fields from another extension into a form.

To simulare the problem

• Enable the user registration
• Create a custom text field called "Foobar" in com_users
• Create a custom list field called "Foobar" in com_contact (and add some options)
• Go to and add the following code to components/com_users/tmpl/registration/default.php line 23:

Joomla\Component\Fields\Administrator\Helper\FieldsHelper::prepareForm('com_contact.contact', $this->form, []);

• Go to the user registration

Expected result

two "Foobar" fields visible

Actual problem

Only one "Foobar" field is loaded, the fields are conflicting. This has also different effect when e.g. saving etc.

Solution

I like in general the idea of the original PR, but it has to be in a Major version respecting the B/C rules.

@Hackwar

[laoneo]

Thanks @bembelimen!

[richard67]

I have tested this item ✅ successfully on 2cba929

Hint for other testers: When having applied this PR, it is not enough just to visit the user registration again to see both fields. You have to edit one of the 2 fields again (or proceed again from the start where you have none of these fields yet). Then you won't be able to save the field (2nd in case if you started again from scratch). You have to manually chose a different name, then you can save, and then you will see both fields in the user registration.

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[Quy]

I have tested this item ✅ successfully on 2cba929

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/44462.}

[Quy]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/44462.}

[HLeithner]

Thanks