List_display_links validation error is not being caught correctly

[Robert Myers <myer0052@…>]

In djaongo.core.management the list_display_links validation checks to see if list_display is used. But the check is either not working or does not stop the validation of the admin option.

Testing included in #3217

Example:

class ListDisplayLinksBadThree(models.Model):
    "Test list_display_links, must define list_display to use list_display_links."
    first_name = models.CharField(maxlength=30)
    last_name = models.CharField(maxlength=30)
    
    class Admin:
        list_display_links = ('first_name',)

Expecting error:

"admin.list_display" must be defined for "admin.list_display_links" to be used.

That error is being ignored and the resulting error is displayed:

"admin.list_display_links" refers to 'first_name', which is not defined in "admin.list_display".

[Robert Myers <myer0052@…>]

This error is not really an error. The validation does not work properly because list_display is set to the default of ('str',). So even if you do not define it in your admin class list_display is always defined, so the validation_error returned is correct in this instance.