Display a running diff in the object history list page

AUTHORS.rst

@@ -39,6 +39,7 @@ Authors
 - David Grochowski (`ThePumpingLemma <https://github.com/ThePumpingLemma>`_)
 - David Hite
 - David Smith
+- David Toulmin (`davidtoulmin <https://github.com/davidtoulmin>`_)
 - `ddabble <https://github.com/ddabble>`_
 - Dmytro Shyshov (`xahgmah <https://github.com/xahgmah>`_)
 - Edouard Richard (`vied12 <https://github.com/vied12>` _)

CHANGES.rst

@@ -16,6 +16,7 @@ Unreleased
   version is lower than 4.2 (gh-1261)
 - Small performance optimization of the ``clean-duplicate_history`` command (gh-1015)
 - Support Simplified Chinese translation (gh-1281)
+- Added a running diff to the _object_history_list.html so users can see a list of all field changes made in each change
 
 3.4.0 (2023-08-18)
 ------------------

simple_history/admin.py

@@ -70,6 +70,15 @@ def history_view(self, request, object_id, extra_context=None):
                 for list_entry in action_list:
                     setattr(list_entry, history_list_entry, value_for_entry(list_entry))
 
+        previous = None
+        for list_entry in reversed(action_list):
+            if previous:
+                value = list_entry.diff_against(previous).changes
+            else:
+                value = ""
+            setattr(list_entry, "diff", value)
+            previous = list_entry
+
         content_type = self.content_type_model_cls.objects.get_for_model(
             get_user_model()
         )

simple_history/templates/simple_history/_object_history_list.html

@@ -10,6 +10,7 @@
       {% for column in history_list_display %}
         <th scope="col">{% trans column %}</th>
       {% endfor %}
+      <th scope="col">{% trans 'Changes from previous' %}</th>
       <th scope="col">{% trans 'Date/time' %}</th>
       <th scope="col">{% trans 'Comment' %}</th>
       <th scope="col">{% trans 'Changed by' %}</th>
@@ -21,8 +22,9 @@
       <tr>
         <td><a href="{% url opts|admin_urlname:'simple_history' object.pk action.pk %}">{{ action.history_object }}</a></td>
         {% for column in history_list_display %}
-        <td scope="col">{{ action|getattribute:column }}</th>
+        <td scope="col">{{ action|getattribute:column }}</td>
         {% endfor %}
+        <td>{% include "simple_history/diff_table.html" with diff=action.diff %}</td>
         <td>{{ action.history_date }}</td>
         <td>{{ action.get_history_type_display }}</td>
         <td>

simple_history/templates/simple_history/diff_table.html

@@ -0,0 +1,21 @@
+{% load i18n %}
+{% if diff %}
+<table>
+    <thead>
+        <th>{% trans 'Field' %}</th>
+        <th>{% trans 'Old Value' %}</th>
+        <th>{% trans 'New Value' %}</th>
+    </thead>
+    <tbody>
+    {% for change in diff %}
+        <tr>
+            <td>{{ change.field }}</td>
+            <td>{{ change.old }}</td>
+            <td>{{ change.new }}</td>
+        </tr>
+    {% endfor %}
+    </tbody>
+</table>
+{% else %}
+{% trans 'No Change' %}
+{% endif %}