Calling reload on deleted / nonexistant documents raises DoesNotExist (#538)

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 
 Changes in 0.8.7
 ================
+- Calling reload on deleted / nonexistant documents raises DoesNotExist (#538)
 - Stop ensure_indexes running on a secondaries (#555)
 - Fix circular import issue with django auth (#531) (#545)
 

docs/upgrade.rst

@@ -2,6 +2,12 @@
 Upgrading
 #########
 
+0.8.7
+*****
+
+Calling reload on deleted / nonexistant documents now raises a DoesNotExist
+exception.
+
 
 0.8.2 to 0.8.3
 **************

mongoengine/document.py

@@ -12,6 +12,7 @@ from mongoengine.common import _import_class
 from mongoengine.base import (DocumentMetaclass, TopLevelDocumentMetaclass,
                               BaseDocument, BaseDict, BaseList,
                               ALLOW_INHERITANCE, get_document)
+from mongoengine.errors import ValidationError
 from mongoengine.queryset import OperationError, NotUniqueError, QuerySet
 from mongoengine.connection import get_db, DEFAULT_CONNECTION_NAME
 from mongoengine.context_managers import switch_db, switch_collection
@@ -452,14 +453,16 @@ class Document(BaseDocument):
         .. versionadded:: 0.1.2
         .. versionchanged:: 0.6  Now chainable
         """
+        if not self.pk:
+            raise self.DoesNotExist("Document does not exist")
         obj = self._qs.read_preference(ReadPreference.PRIMARY).filter(
-                **self._object_key).limit(1).select_related(max_depth=max_depth)
+                    **self._object_key).limit(1).select_related(max_depth=max_depth)
+
 
         if obj:
             obj = obj[0]
         else:
-            msg = "Reloaded document has been deleted"
+            raise self.DoesNotExist("Document does not exist")
-            raise OperationError(msg)
         for field in self._fields_ordered:
             setattr(self, field, self._reload(field, obj[field]))
         self._changed_fields = obj._changed_fields

tests/document/instance.py

@@ -409,6 +409,27 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(len(doc.embedded_field.list_field), 4)
         self.assertEqual(len(doc.embedded_field.dict_field), 2)
 
+    def test_reload_doesnt_exist(self):
+        class Foo(Document):
+            pass
+
+        f = Foo()
+        try:
+            f.reload()
+        except Foo.DoesNotExist:
+            pass
+        except Exception as ex:
+            self.assertFalse("Threw wrong exception")
+
+        f.save()
+        f.delete()
+        try:
+            f.reload()
+        except Foo.DoesNotExist:
+            pass
+        except Exception as ex:
+            self.assertFalse("Threw wrong exception")
+
     def test_dictionary_access(self):
         """Ensure that dictionary-style field access works properly.
         """