\begin{datadesc}{garbage}
A list of objects which the collector found to be unreachable
-but could not be freed (uncollectable objects). Objects that have
+but could not be freed (uncollectable objects). By default, this list
+contains only objects with \method{__del__()} methods.\footnote{Prior to
+ Python 2.2, the list contained all instance objects in unreachable
+ cycles, not only those with \method{__del__()} methods.}
+Objects that have
\method{__del__()} methods and create part of a reference cycle cause
the entire reference cycle to be uncollectable. If
\constant{DEBUG_SAVEALL} is set, then all unreachable objects will
Extension modules
+- By default, the gc.garbage list now contains only those instances in
+ unreachable cycles that have __del__ methods; in 2.1 it contained all
+ instances in unreachable cycles. "Instances" here has been generalized
+ to include instances of both new-style and old-style classes.
+
- The socket module defines a new method for socket objects,
sendall(). This is like send() but may make multiple calls to
send() until all data has been sent. Also, the socket function has