ModelAdmin.empty_value_display example in docs should use list_display.

[Michael]

Firstly, the documentation is great. In the ​admin site docs, it has this example:

from django.contrib import admin

class AuthorAdmin(admin.ModelAdmin):
    fields = ('name', 'title', 'view_birth_date')

    @admin.display(empty_value='???')
    def view_birth_date(self, obj):
        return obj.birth_date]

I think this will only work for the list display, not setting the empty value of the field during edit view.
Hence I think

fields = ('name', 'title', 'view_birth_date')

should become

list_display = ('name', 'title', 'view_birth_date')

[Mariusz Felisiak]

I think this will only work for the list display, not setting the empty value of the field during edit view.

It also works for readonly_fields, but I agree that list_display fits better here. Would you like to provide a patch?

[Michael]

Sure I will create a patch, before I submit it, would you please review the following, because I am not 100% sure I understand how the readonly functionality works for the empty_value:

Change from:

    You can also override ``empty_value_display`` for all admin pages with
    :attr:`AdminSite.empty_value_display`, or for specific fields like this::

        from django.contrib import admin

        class AuthorAdmin(admin.ModelAdmin):
            fields = ('name', 'title', 'view_birth_date')

            @admin.display(empty_value='???')
            def view_birth_date(self, obj):
                return obj.birth_date

To:

    You can also override ``empty_value_display`` for all admin pages with
    :attr:`AdminSite.empty_value_display`.
    
    To override just a specific ``list_display`` field, or one of the
    ``readonly_fields``, one can do so like this::

        from django.contrib import admin

        class AuthorAdmin(admin.ModelAdmin):
            list_display = ('name', 'title', 'view_birth_date')
            readonly_fields = ('view_birth_date', )
            fields = ('name', 'title', 'view_birth_date')

            @admin.display(empty_value='???')
            def view_birth_date(self, obj):
                return obj.birth_date

[Mariusz Felisiak]

IMO it's not important to mention readonly_fields in ModelAdmin.empty_value_display docs, it's already documented in the display() decorator. I would only change fields to list_display:

docs/ref/contrib/admin/index.txt

@@ -249 +249 @@
         from django.contrib import admin
 
         class AuthorAdmin(admin.ModelAdmin):
-            fields = ('name', 'title', 'view_birth_date')
+            list_display = ('name', 'title', 'view_birth_date')
 
             @admin.display(empty_value='???')
             def view_birth_date(self, obj):

[Mariusz Felisiak]

​PR

[Mariusz Felisiak]

Fixed in eb901681ab58c008f7bbbe555e5f43f8e0893bd3 and b93fb3d6be944bd196a6a7be576f0622c4e3f59c.