Add part category tree traversal

- If a category doesn't have a default_location, look at the parent category
- And so on and so on

InvenTree/part/models.py

@@ -159,8 +159,16 @@ class Part(models.Model):
         if self.default_location:
             return self.default_location
         elif self.category:
-            return self.category.default_location
+            # Traverse up the category tree until we find a default location
+            cat = self.category
 
+            while cat:
+                if cat.default_location:
+                    return cat.default_location
+                else:
+                    cat = cat.parent
+
+        # Default case - no default category found
         return None
 
     # Default supplier part

InvenTree/part/templates/part/category.html

@@ -8,8 +8,11 @@
     {% if category %}
     <h3>{{ category.name }}</h3>
     <p>{{ category.description }}</p>
+    {% if category.default_location %}
+    <p>Default Location: <a href="{% url 'stock-location-detail' category.default-location.id }%">{{ category.default_location }}</a></p>
+    {% endif %}
     {% else %}
-    <h3>Parts</h3>
+    <h3>Part Categories</h3>
     {% endif %}
 </div>
 <div class='col-sm-6'>