I'm not *entirely* sure what's going on here, but it seems that when we
do something like
obj = OpaqueObject(...)
Session = sessionmaker(...)
session = Session()
...
session.add(obj)
session.commit()
the primary key (and maybe some foreign relations?) aren't automatically
populated on `obj` following the commit, and will attempt to lazy-load
on next reference. Since expire_on_commit defaults to True, the session
attached to `obj` (which is no longer the `session` in locals!) is closed
out when we later do
session = Session()
get_obj = session.query(OpaqueObject).filter(
ManagedObject.unique_identifier == obj.unique_identifier).one()
leading to a DetachedInstanceError.
There seem to be a few different ways we can fix this:
* Set expire_on_commit=False so the old session is still useful for the
lazy-loading.
* Re-use the same session instead of creating a new one.
* Explicitly refresh added objects post-commit.
Generally prefer the first one; there's some prior art to follow in
services/server/test_engine.py. Curiously, that same file runs into
trouble despite already setting expire_on_commit=False -- so do the
explicit refresh, on the assumption that there was a reason we went to
the trouble of creating a fresh session.
Closes#649
This change adds a SecretData class to the Pie object hierarchy. A unit
test suite covering the class is provided, as are updates to the Pie
object factory and associated tests.
