- add message to documentation stating that collection validators cannot

load the collection being validated. [ticket:1916]

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 9e38ac8119ec59461b490acc0fe7e0a03fe84380..816bf95bf56332aa35a0508b7d18654f3759b121 100644 (file)
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -2373,6 +2373,11 @@ def validates(*names):
     can then raise validation exceptions to halt the process from continuing,
     or can modify or replace the value before proceeding.   The function
     should otherwise return the given value.
+    
+    Note that a validator for a collection **cannot** issue a load of that
+    collection within the validation routine - this usage raises
+    an assertion to avoid recursion overflows.  This is a reentrant
+    condition which is not supported.
 
     """
     def wrap(fn):