Python 2.5-incompatible change in r16319 -- ModelAdmin.list_display.index method called

[Simon Meers]

r16319 introduced a python 2.5-incompatible change in which ModelAdmin.list_display's index method is called despite the fact that it is likely a tuple (which only has an index method in 2.6+).

I imagine this managed to hide for so long because:

• No tests failed -- some use lists for list_display, and most don't have ordering set on the ModelAdmin or Model.Meta
• ChangeLists for which actions were present (which they are by default) have their list_display listified when action_checkbox is prepended (bypassed if rendering the result_list without using changelist_view)
• The number of people using Django trunk with Python 2.5 are no doubt a minority

I've attached a patch which addresses the issue and includes regression tests, which I'll commit unless someone thinks it could be done better.

[Aymeric Augustin]

This looks good to me.

[Jannis Leidel]

In [17102]:

Fixed #17128 -- Fixed a Python 2.5 incompatibility. Thanks, Simon Meers.