Fixed infinite recursion bug in _geo_indices()

Fixes #213  Thanks to joshink for the bug report

mongoengine/base.py

@@ -754,11 +754,16 @@ class BaseDocument(object):
         return set_data, unset_data
 
     @classmethod
-    def _geo_indices(cls):
+    def _geo_indices(cls, inspected_classes=None):
+        inspected_classes = inspected_classes or []
         geo_indices = []
+        inspected_classes.append(cls)
         for field in cls._fields.values():
             if hasattr(field, 'document_type'):
-                geo_indices += field.document_type._geo_indices()
+                field_cls = field.document_type
+                if field_cls in inspected_classes:
+                    continue
+                geo_indices += field_cls._geo_indices(inspected_classes)
             elif field._geo_index:
                 geo_indices.append(field)
         return geo_indices

tests/document.py

@@ -662,6 +662,18 @@ class DocumentTest(unittest.TestCase):
 
         BlogPost.drop_collection()
 
+    def test_geo_indexes_recursion(self):
+
+        class User(Document):
+            channel = ReferenceField('Channel')
+            location = GeoPointField()
+
+        class Channel(Document):
+            user = ReferenceField('User')
+            location = GeoPointField()
+
+        self.assertEquals(len(User._geo_indices()), 2)
+
     def test_hint(self):
 
         class BlogPost(Document):