Not the upserted entities themselves, no matter if expunged or made transient.
Reminder to my future self: returning the flushed entities and then using them
outside of the session or in another thread opens a big can of worms when using
SQLAlchemy.
- Added `wait_start()` method that other threads can use to synchronize
with the engine and wait before performing db operations.
- Callback logic wrapped in a try/except block to prevent custom
integrations with buggy callbacks from crashing the engine.
- Support for an optional callback on `publish_entities` to get notified
when the published object are flushed to the db.
- Use `lazy='selectin'` for the entity parent -> children relationship -
it is more efficient and it ensures that all the data the application
needs is loaded upfront.
- `Entity.entity_key` rolled back to `<external_id, plugin>`. The
fallback logic on `<id, plugin>` created more problems than those it
as supposed to solve.
- Added `expire_on_commit=False` to the entities engine session to make
sure that we don't get errors on detached/expired instances.
- Better logic to recursively link parent/children entities, so partial
updates won't get lost.
- Removed `EntitiesCache` - it was too much to maintain while keeping
consistent with the ORM, and it was a perennial fight against
SQLAlchemy's own cache.
- Removed `EntityNotifier` - with no need to merge cached entities, the
`notify` method has become much simpler and it's simply been merged
in the `EntitiesRepository`.
This may make things a bit less optimal, but it's probably the only
possible solution that preserves my sanity.
Managing upserts of cached instances that were previously made transient
and expunged from the session is far from easy, and the management of
recursive parent/children relationships only add one more layer of
complexity (and that management is already complex enough in its current
implementation).
Fabio Manganiello