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John Davis
377f783e20
Rationale:
We use an in-memory sqlite database for quota tests. With SA 2.0 (or
with the `future` flag enabled on the engine), the following conflict
happens: (this is a simplified model)
foo = Foo()
session.add(foo)
session.flush()
engine = session.get_bind()
with engine.connect() as conn:
conn.execute(some-sql)
foo.bar = "new value"
session.commit() # BOOM!!!! sqlalchemy.orm.exc.StaleDataError: UPDATE statement on table 'galaxy_user' expected to update 1 row(s); 0 were matched.
Reason for BOOM:
With an in-memory database, the underlying dbapi_connection object is
the same for the session and the engine.connect(). Here's what happens:
line 10: foo is flushed to the db tmp buffer
line 14: conn is closed on exit from context manager, which issues a
rollback, which rolls back whatever is in the tmp buffer - so foo is
never inserted.
line 16: foo is updated
line 17: error happens: the session thinks it's updating foo's record in
the db, but that record does not exist therefore, "0 rows matched".
Solution: commit instead of flushing - then foo is inserted.