Add warning when CAS paths are skipped and ensure we are under a transaction

data/database.py

@@ -7,6 +7,7 @@ import sys
 import time
 import uuid
 
+from contextlib import contextmanager
 from collections import defaultdict
 from datetime import datetime
 from random import SystemRandom
@@ -230,6 +231,7 @@ db_match_func = CallableProxy()
 db_for_update = CallableProxy()
 db_transaction = CallableProxy()
 db_concat_func = CallableProxy()
+ensure_under_transaction = CallableProxy()
 
 
 def validate_database_url(url, db_kwargs, connect_timeout=5):
@@ -286,7 +288,16 @@ def configure(config_object):
   def _db_transaction():
     return config_object['DB_TRANSACTION_FACTORY'](db)
 
+  @contextmanager
+  def _ensure_under_transaction():
+    if not config_object['TESTING']:
+      if db.transaction_depth() == 0:
+        raise Exception('Expected to be under a transaction')
+
+    yield
+
   db_transaction.initialize(_db_transaction)
+  ensure_under_transaction.initialize(_ensure_under_transaction)
 
 def random_string_generator(length=16):
   def random_string():