- Calling fetchone() or similar on a result that

has already been exhausted, has been closed,
or is not a result-returning result now
raises ResourceClosedError, a subclass of
InvalidRequestError, in all cases, regardless
of backend.  Previously, some DBAPIs would
raise ProgrammingError (i.e. pysqlite), others
would return None leading to downstream breakages
(i.e. MySQL-python).

- Connection, ResultProxy, as well as Session use
ResourceClosedError for all "this
connection/transaction/result is closed" types of
errors.

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/sqlalchemy/exc.py b/lib/sqlalchemy/exc.py
index 31826f44f..1c412824c 100644
--- a/lib/sqlalchemy/exc.py
+++ b/lib/sqlalchemy/exc.py
@@ -60,6 +60,10 @@ class InvalidRequestError(SQLAlchemyError):
 
     """
 
+class ResourceClosedError(InvalidRequestError):
+    """An operation was requested from a connection, cursor, or other
+    object that's in a closed state."""
+    
 class NoSuchColumnError(KeyError, InvalidRequestError):
     """A nonexistent column is requested from a ``RowProxy``."""