Use model meta to generate verbose name (#54)

Render field names of object rather than the word "None"

This is fix for issue #53, since an object may not exist when rendering
`templates/admin/change_data.html` - ie, if we're greating a new object
when `confirm_add = True` is set on a `ModelAdmin` with
the `AdminConfirmMixin`.

Also makes sure we send an actual object (not the string "None") to the
base template, to remove other instances of the word "None" from
the add view.

Co-authored-by: T Pham <thuutrangpham@gmail.com>

Author: dtcooper

admin_confirm/admin.py

@@ -428,8 +428,8 @@ def _change_confirmation_view(self, request, object_id, form_url, extra_context)
             **self.admin_site.each_context(request),
             "preserved_filters": self.get_preserved_filters(request),
             "title": f"{_('Confirm')} {title_action} {opts.verbose_name}",
-            "subtitle": str(obj),
-            "object_name": str(obj),
+            "subtitle": obj and str(obj),
+            "object_name": obj and str(obj),
             "object_id": object_id,
             "app_label": opts.app_label,
             "model_name": opts.model_name,

admin_confirm/templatetags/formatting.py

@@ -22,5 +22,4 @@ def format_change_data_field_value(field_value):
 @register.simple_tag
 def verbose_name(opts, fieldname):
     # opts is set within context and is equal to model._meta
-    if opts:
-        return opts.get_field(fieldname).verbose_name
+    return opts.get_field(fieldname).verbose_name.capitalize()