:class:`.AttributeImpl` as an "initiator" token has been changed; the object is now an event-specific object called :class:`.attributes.Event`. Additionally, the attribute system no longer halts events based on a matching "initiator" token; this logic has been moved to be specific to ORM backref event handlers, which are the typical source of the re-propagation of an attribute event onto subsequent append/set/remove operations. End user code which emulates the behavior of backrefs must now ensure that recursive event propagation schemes are halted, if the scheme does not use the backref handlers. Using this new system, backref handlers can now peform a "two-hop" operation when an object is appended to a collection, associated with a new many-to-one, de-associated with the previous many-to-one, and then removed from a previous collection. Before this change, the last step of removal from the previous collection would not occur. [ticket:2789]
when loading mapped entities. The function overhead of applying a per-object deferred callable to an instance at load time was significantly higher than that of just loading the data from the row (note that ``defer()`` is meant to reduce DB/network overhead, not necessarily function call count); the function call overhead is now less than that of loading data from the column in all cases. There is also a reduction in the number of "lazy callable" objects created per load from N (total deferred values in the result) to 1 (total number of deferred cols). [ticket:2778]
when an object we moved from "persistent" to "pending" using the :func:`.make_transient` function, for operations involving collection-based backrefs. [ticket:2773]
- went through examples/ and cleaned out excess list() calls
mapper configuration; will now test for name conflicts on superclasses and subclasses, in addition to the current mapper, as these conflicts break things just as much. This is new for 0.8, but see below for a warning that will also be triggered in 0.7.11. - Improved the error message emitted when a "backref loop" is detected, that is when an attribute event triggers a bidirectional assignment between two other attributes with no end. This condition can occur not just when an object of the wrong type is assigned, but also when an attribute is mis-configured to backref into an existing backref pair. Also in 0.7.11. - A warning is emitted when a MapperProperty is assigned to a mapper that replaces an existing property, if the properties in question aren't plain column-based properties. Replacement of relationship properties is rarely (ever?) what is intended and usually refers to a mapper mis-configuration. Also in 0.7.11. [ticket:2674]
on a never-set collection would fail; made this act just like scalars for now and added tests. I would think that HISTORY_BLANK would be more appropriate here but it's too late in the game to mess with that.
become an externally usable package but still remains within the main sqlalchemy parent package. in this system, we use kind of an ugly hack to get the noseplugin imported outside of the "sqlalchemy" package, while still making it available within sqlalchemy for usage by third party libraries.