Ticket #5741: get_with_default.diff

django/db/models/query.py

@@ -300 +300 @@
         Performs the query and returns a single object matching the given
         keyword arguments.
         """
+        has_default = False
+        if 'default' in kwargs:
+            default_value = kwargs.pop('default')
+            has_default = True
         clone = self.filter(*args, **kwargs)
         num = len(clone)
         if num == 1:
             return clone._result_cache[0]
         if not num:
+            if has_default:
+                return default_value
             raise self.model.DoesNotExist("%s matching query does not exist."
                     % self.model._meta.object_name)
         raise self.model.MultipleObjectsReturned("get() returned more than one %s -- it returned %s! Lookup parameters were %s"

docs/ref/models/querysets.txt

@@ -727 +727 @@
     except ObjectDoesNotExist:
         print "Either the entry or blog doesn't exist."
 
+.. versionadded:: development
+
+You can optionally pass in a keyword argument called ``default`` to ``get()``.
+If the object being requested does not exist and a default value is given, the
+default value will be returned, instead of raising a ``DoesNotExist``
+exception. For example::
+
+    e = Entry.objects.get(id=3, default=None)
+
+... would set ``e`` to ``None`` if no such ``Entry`` existed.
+
+Since this default argument name might potentially clash with a model field
+called ``default``, if you wish to filter on a field called ``default``, you
+should write the filter as ``default__exact``::
+
+    SomeModel.objects.get(default__exact=3)
+
+This will filter on the ``default`` field, rather than specifying a default
+return value.
+
 ``create(**kwargs)``
 ~~~~~~~~~~~~~~~~~~~~
 

tests/modeltests/basic/models.py

@@ -100 +100 @@
     ...
 DoesNotExist: Article matching query does not exist.
 
+# You can specify a default keyword argument to get()
+>>> Article.objects.get(pk=97, default=False)
+False
+
 # Lookup by a primary key is the most common case, so Django provides a
 # shortcut for primary-key exact lookups.
 # The following is identical to articles.get(id=1).