Simple workaround to ignore FieldDoesNotExist with custom fields

admin_confirm/admin.py

@@ -3,7 +3,7 @@
 from django.contrib.admin.exceptions import DisallowedModelAdminToField
 from django.contrib.admin.utils import flatten_fieldsets, unquote
 from django.core.cache import cache
-from django.core.exceptions import PermissionDenied
+from django.core.exceptions import PermissionDenied, FieldDoesNotExist
 from django.template.response import TemplateResponse
 from django.contrib.admin.options import TO_FIELD_VAR
 from django.utils.translation import gettext as _
@@ -176,13 +176,17 @@ def _display_for_changed_data(field, initial_value, new_value):
         if add:
             for name, new_value in form.cleaned_data.items():
                 # Don't consider default values as changed for adding
-                field_object = model._meta.get_field(name)
-                default_value = field_object.get_default()
-                if new_value is not None and new_value != default_value:
-                    # Show what the default value is
-                    changed_data[name] = _display_for_changed_data(
-                        field_object, default_value, new_value
-                    )
+                try:
+                    field_object = model._meta.get_field(name)
+                    default_value = field_object.get_default()
+                    if new_value is not None and new_value != default_value:
+                        # Show what the default value is
+                        changed_data[name] = _display_for_changed_data(
+                            field_object, default_value, new_value
+                        )
+                except FieldDoesNotExist:
+                    # Ignore custom fields
+                    pass
         else:
             # Parse the changed data - Note that using form.changed_data would not work because initial is not set
             for name, new_value in form.cleaned_data.items():