Fixed issue where if an exception occurred when the :class:`_orm.Session` were to close the connection within the :meth:`_orm.Session.commit` method, when using a context manager for :meth:`_orm.Session.begin` , it would attempt a rollback which would not be possible as the :class:`_orm.Session` was in between where the transaction is committed and the connection is then to be returned to the pool, raising the exception "this sessiontransaction is in the committed state". This exception can occur mostly in an asyncio context where CancelledError can be raised. Fixes: #7388 Change-Id: I1a85a3a7eae79f3553ddf1e3d245a0d90b0a2f40
This is so that dialect methods that are called within init can assume the same argument structure as when they are called in other places; we can nail down the type of object as well. This change seems to mostly impact the isolation level routines in the dialects, as these are called during initialize() as well as on established connections. these methods can now assume a non-proxied DBAPI connection object in all cases, as it is commonly required that attributes like ".autocommit" are set on the object which don't work well in a proxied situation. Other changes: * adds an interface for the "connectionfairy" concept called PoolProxiedConnection. * Removes ``Connectable`` superclass of Connection. ``Connectable`` was originally meant to provide for the "method which accepts connection or engine" theme. As this pattern is greatly reduced in 2.0 and Engine no longer extends from it, the ``Connectable`` superclass doesnt serve any real purpose. Leading from that, to set this in I also applied pep 484 annotations to the Dialect base, and then in the interests of seeing some of the typing information show up in my IDE did a little bit for Engine, Connection and others. I hope that it's feasible that we can add annotations to specific classes and attributes ahead of when we actually try to mass-populate the whole library. This was the original spirit of pep-484 that we can apply annotations gradually. I do of course want to try to do a mass-populate although i think even in that case we will end up doing a lot of manual work anyway (in particular for the changes here which are distinct from what the stubs have). Fixes: #7122 Change-Id: I5dd7fbff8a7ae520a81c165091af12a6a68826db
Change-Id: I8172fdcc3103ff92aa049827728484c8779af6b7
References: #4600 Change-Id: I2a62ddfe00bc562720f0eae700a497495d7a987a
Generalized the :paramref:`_sa.create_engine.isolation_level` parameter to the base dialect so that it is no longer dependent on individual dialects to be present. This parameter sets up the "isolation level" setting to occur for all new database connections as soon as they are created by the connection pool, where the value then stays set without being reset on every checkin. The :paramref:`_sa.create_engine.isolation_level` parameter is essentially equivalent in functionality to using the :paramref:`_engine.Engine.execution_options.isolation_level` parameter via :meth:`_engine.Engine.execution_options` for an engine-wide setting. The difference is in that the former setting assigns the isolation level just once when a connection is created, the latter sets and resets the given level on each connection checkout. Fixes: #6342 Change-Id: Id81d6b1c1a94371d901ada728a610696e09e9741
The major action here is to lift and move future.Connection and future.Engine fully into sqlalchemy.engine.base. This removes lots of engine concepts, including: * autocommit * Connection running without a transaction, autobegin is now present in all cases * most "autorollback" is obsolete * Core-level subtransactions (i.e. MarkerTransaction) * "branched" connections, copies of connections * execution_options() returns self, not a new connection * old argument formats, distill_params(), simplifies calling scheme between engine methods * before/after_execute() events (oriented towards compiled constructs) don't emit for exec_driver_sql(). before/after_cursor_execute() is still included for this * old helper methods superseded by context managers, connection.transaction(), engine.transaction() engine.run_callable() * ancient engine-level reflection methods has_table(), table_names() * sqlalchemy.testing.engines.proxying_engine References: #7257 Change-Id: Ib20ed816642d873b84221378a9ec34480e01e82c
As future connections will now be autobeginning, there will be more cases where begin() can't be called as well as where isolation level can't be set, which will be surprising as this is a behavioral change for 2.0; additionally, when DBAPI autocommit is set, there isn't actually a DBAPI level transaction in effect even though Connection has a Transaction object. Clarify the language in these two error messages to make it clear that begin() and autobegin are tracking a SQLAlchemy-level Transaction() object, whether or not the DBAPI has actually started a transaction, and that this is the reason rollback() or commit() is required before performing the requsted operation. Additionally make sure the error message mentions "autobegin" as a likely reason this error is being encountered along with what Connection needs the user to do in order to resolve. Change-Id: If8763939eeabc46aa9d9209a56d05ad82b892c5c
Applied consistent behavior to the use case of calling ``.commit()`` or ``.rollback()`` inside of an existing ``.begin()`` context manager, with the addition of potentially emitting SQL within the block subsequent to the commit or rollback. This change continues upon the change first added in :ticket:`6155` where the use case of calling "rollback" inside of a ``.begin()`` contextmanager block was proposed: * calling ``.commit()`` or ``.rollback()`` will now be allowed without error or warning within all scopes, including that of legacy and future :class:`_engine.Engine`, ORM :class:`_orm.Session`, asyncio :class:`.AsyncEngine`. Previously, the :class:`_orm.Session` disallowed this. * The remaining scope of the context manager is then closed; when the block ends, a check is emitted to see if the transaction was already ended, and if so the block returns without action. * It will now raise **an error** if subsequent SQL of any kind is emitted within the block, **after** ``.commit()`` or ``.rollback()`` is called. The block should be closed as the state of the executable object would otherwise be undefined in this state. Fixes: #6288 Change-Id: I8b21766ae430f0fa1ac5ef689f4c0fb19fc84336
Restored a legacy transactional behavior that was inadvertently removed from the :class:`_engine.Connection` as it was never tested as a known use case in previous versions, where calling upon the :meth:`_engine.Connection.begin_nested` method, when no transaction were present, would not create a SAVEPOINT at all, and would instead only start the outermost transaction alone, and return that :class:`.RootTransaction` object, acting like the outermost transaction. Committing the transaction object returned by :meth:`_engine.Connection.begin_nested` would therefore emit a real COMMIT on the database connection. This behavior is not at all what the 2.0 style connection will do - in 2.0 style, calling :meth:`_future.Connection.begin_nested` will "autobegin" the outer transaction, and then as instructed emit a SAVEPOINT, returning the :class:`.NestedTransaction` object. The outer transaction is committed by calling upon :meth:`_future.Connection.commit`, as is "commit-as-you-go" style usage. In non-"future" mode, while the old behavior is restored, it also emits a 2.0 deprecation warning as this is a legacy behavior. Additionally clarifies and reformats various engine-related documentation, in particular future connection.begin() which was a tire fire. Fixes: #6408 Change-Id: I4b81cc6b481b5493eef4c91bebc03210e2206d39
Fixed critical regression caused by the change in :ticket`5497` where the connection pool "init" phase no longer occurred within mutexed isolation, allowing other threads to proceed with the dialect uninitialized, which could then impact the compilation of SQL statements. This issue is essentially the same regression which was fixed many years ago in :ticket:`2964` in dd32540dabbee0678530fb1b0868d1eb41572dca, which was missed this time as the test suite fo that issue only tested the pool in isolation, and assumed the "first_connect" event would be used by the Engine. However :ticket:`5497` stopped using "first_connect" and no test detected the lack of mutexing, that has been resolved here through the addition of more tests. This fix also identifies what is probably a bug in earlier versions of SQLAlchemy where the "first_connect" handler would be cancelled if the initializer failed; this is evidenced by test_explode_in_initializer which was doing a reconnect due to c.rollback() yet wasn't hanging. We now solve this issue by preventing the manufactured Connection from ever reconnecting inside the first_connect handler. Also remove the "_sqla_unwrap" test attribute; this is almost not used anymore however we can use a more targeted wrapper supplied by the testing.engines.proxying_engine function. See if we can also open up Oracle for "ad hoc engines" tests now that we have better connection management logic. Fixes: #6337 Change-Id: I4a3476625c4606f1a304dbc940d500325e8adc1a