[fix] Fixed CopyableFieldsAdmin fields order #335

[Aryamanz29]

Before

After

Fixes #335

[coveralls]

Coverage: 98.8% (+0.002%) from 98.798% when pulling 5deafdb81d0c378dad048be9801499952a0a1988 on issue-335/fix-copyable-admin-field-order into b10d3cdd1f3eadf3d224ccb5f078221b181f6721 on master.

[Aryamanz29]

I found that it's the conversion of a tuple to a set or vice versa that causes the random admin field order @nemesisdesign.

Without patch

• When we convert a tuple to a set in python, the order of the elements in the tuple is not preserved because sets do not have an inherent order. Sets are implemented using a hash table, which means that the elements are stored in an arbitrary order based on their hash values. This order can change each time the set is created or modified, that's why I removed this in cb78d18 (#336)

Similar post here : https://stackoverflow.com/questions/66575621/does-python-tupleset-maintains-order

• When running the below sample test (test_copyablefields_admin_fields_order) a few times, it gives me a different result each time:

    def test_copyablefields_admin_fields_order(self):
        path = reverse('admin:test_project_project_add')
        response = self.client.get(path)
        ma = ProjectAdmin(Project, self.site)
        # uuid should be missing in ma.get_fields  
        # because we're testing project admin add form
        print(ma.fields, ma.get_fields(self.client.request))
        print(ma.readonly_fields, ma.get_readonly_fields(self.client.request))   

Results:

You may have noticed that we are receiving random admin field orders, as shown below. Therefore, if you remove this patch and run the new test case that I recently added in 5deafdb (#336), it is possible that the test might pass instead of failing. This is because the set conversion behavior, which I already explained above.