may be called against a stale connection without the "connect" event handler having been called, in the case where the pool attempted to reconnect after being invalidated and failed; the stale connection would remain present and would be used on a subsequent attempt. This issue has a greater impact in the 1.0 series subsequent to 1.0.2, as it also delivers a blanked-out ``.info`` dictionary to the event handler; prior to 1.0.2 the ``.info`` dictionary is still the previous one. fixes #3497
and the database can no longer be connected towards, that the checkout handler failure is caught, the attempt to re-acquire the connection also raises an exception, but the underlying connection record is not immediately re-checked in before the exception is propagated outwards, having the effect that the checked-out record does not close itself until the stack trace it's associated with is garbage collected, preventing that record from being used for a new checkout until we leave the scope of the stack trace. This can lead to confusion in the specific case of when the number of current stack traces in memory exceeds the number of connections the pool can return, as the pool will instead begin to raise errors about no more checkouts available, rather than attempting a connection again. The fix applies a checkin of the record before re-raising. fixes #3419
using descriptors; ensure that mock.patch() honors descriptor setters
old / new style, direct access, and ad-hoc patching and unpatching as possible
functionality. Added a new "soft invalidate" feature to the connection pool at the level of the checked out connection wrapper as well as the :class:`._ConnectionRecord`. This works similarly to a modern pool invalidation in that connections aren't actively closed, but are recycled only on next checkout; this is essentially a per-connection version of that feature. A new event :class:`.PoolEvents.soft_invalidate` is added to complement it. fixes #3379 - Added new flag :attr:`.ExceptionContext.invalidate_pool_on_disconnect`. Allows an error handler within :meth:`.ConnectionEvents.handle_error` to maintain a "disconnect" condition, but to handle calling invalidate on individual connections in a specific manner within the event. - Added new event :class:`.DialectEvents.do_connect`, which allows interception / replacement of when the :meth:`.Dialect.connect` hook is called to create a DBAPI connection. Also added dialect plugin hooks :meth:`.Dialect.get_dialect_cls` and :meth:`.Dialect.engine_created` which allow external plugins to add events to existing dialects using entry points. fixes #3355
:paramref:`.Pool.reset_on_return` parameter as a synonym for ``None``, so that string values can be used for all settings, allowing .ini file utilities like :func:`.engine_from_config` to be usable without issue. fixes #3375
:meth:`.Connection.invalidate` method, or an invalidation due to a database disconnect, would fail if the ``isolation_level`` parameter had been used with :meth:`.Connection.execution_options`; the "finalizer" that resets the isolation level would be called on the no longer opened connection. fixes #3302
allowing us to move to __slots__