Ambiguity of the 'DELETE' text when a TabularInline object does not exist

[Antoliny]

When using a foreign key reverse reference model with TabularInline in ModelAdmin, if the corresponding object does not exist, the 'DELETE' text seems unnecessary.
I feel that the 'DELETE' text helps users remove an object when the TabularInline object exists.
However, if the object doesn't exist, the 'DELETE' text seems to lose its purpose.

[Natalia Bidart]

Hello Antoliny, thank you for taking the time to create this report! I agree with you, the "Delete?" legend is confusing and unnecessary.

[Antoliny]

I explored several approaches to address this issue.
I initially wanted to solve it using conditions directly in the template, but there was no suitable attribute available to determine whether each Formset contains objects.

As a solution, I decided to add a self.has_object attribute to the InlineAdminFormSet, assigning it the return value of self.formset.get_queryset().exists(). This allows the presence of the "DELETE?" text to be determined based on whether objects exist.

However, the downside of this approach is that an attribute is being added solely for the purpose of removing the "DELETE?" text. If you have a better suggestion, I would greatly appreciate your advice.

django/contrib/admin/helpers.py

@@ -337 +337 @@
         self.has_change_permission = has_change_permission
         self.has_delete_permission = has_delete_permission
         self.has_view_permission = has_view_permission
+        self.has_object = self.formset.get_queryset().exists()
 
     def __iter__(self):
         if self.has_change_permission:

django/contrib/admin/templates/admin/edit_inline/tabular.html

@@ -23 +23 @@
        {% if field.help_text %}<img src="{% static "admin/img/icon-unknown.svg" %}" class="help help-tooltip" width="10" height="10" alt="({{ field.help_text|striptags }})" title="{{ field.help_text|striptags }}">{% endif %}
        </th>
      {% endfor %}
-     {% if inline_admin_formset.formset.can_delete and inline_admin_formset.has_delete_permission %}<th>{% translate "Delete?" %}</th>{% endif %}
+     {% if inline_admin_formset.formset.can_delete and inline_admin_formset.has_delete_permission and inline_admin_formset.has_object %}<th>{% translate "Delete?" %}</th>{% endif %}
      </tr></thead>
 
      <tbody>

[Natalia Bidart]

Replying to Antoliny:

As a solution, I decided to add a self.has_object attribute to the InlineAdminFormSet, assigning it the return value of self.formset.get_queryset().exists(). This allows the presence of the "DELETE?" text to be determined based on whether objects exist.

However, the downside of this approach is that an attribute is being added solely for the purpose of removing the "DELETE?" text. If you have a better suggestion, I would greatly appreciate your advice.

I share your concern with your initial diff. There is one extra query being issued which feels unnecessary. I played a bit with this and settled on having something like this, which nicely reduces logic in the template for calculating the header and checkbox row, and it also uses the existing information in the formset:

django/contrib/admin/helpers.py

@@ -460 +460 @@
     def total_form_count(self):
         return self.formset.total_form_count
 
+    @property
+    def can_delete(self):
+        return (
+            self.formset.can_delete
+            and self.has_delete_permission
+            and any(inlineadminform.original is not None for inlineadminform in self)
+        )
+
     @property
     def media(self):
         media = self.opts.media + self.formset.media

django/contrib/admin/templates/admin/edit_inline/tabular.html

@@ -23 +23 @@
        {% if field.help_text %}<img src="{% static "admin/img/icon-unknown.svg" %}" class="help help-tooltip" width="10" height="10" alt="({{ field.help_text|striptags }})" title="{{ field.help_text|striptags }}">{% endif %}
        </th>
      {% endfor %}
-     {% if inline_admin_formset.formset.can_delete and inline_admin_formset.has_delete_permission %}<th>{% translate "Delete?" %}</th>{% endif %}
+     {% if inline_admin_formset.can_delete %}<th>{% translate "Delete?" %}</th>{% endif %}
      </tr></thead>
 
      <tbody>
@@ -58 +58 @@
             {% endfor %}
           {% endfor %}
         {% endfor %}
-        {% if inline_admin_formset.formset.can_delete and inline_admin_formset.has_delete_permission %}
+        {% if inline_admin_formset.can_delete %}
           <td class="delete">{% if inline_admin_form.original %}{{ inline_admin_form.deletion_field.field }}{% endif %}</td>
         {% endif %}
         </tr>

Antoliny, what do you think? This would need a few tests added to existing admin suite.