2.0.38

Released: February 6, 2025

engine

[engine] [bug] Fixed event-related issue where invoking Engine.execution_options()
on a Engine multiple times while making use of event-registering
parameters such as isolation_level would lead to internal errors
involving event registration.

References: #12289

[sql] [bug] Reorganized the internals by which the .c collection on a
FromClause gets generated so that it is resilient against the
collection being accessed in concurrent fashion. An example is creating a
Alias or Subquery and accessing it as a module level
variable. This impacts the Oracle dialect which uses such module-level
global alias objects but is of general use as well.

References: #12302
[sql] [bug] Fixed SQL composition bug which impacted caching where using a None
value inside of an in_() expression would bypass the usual "expanded
bind parameter" logic used by the IN construct, which allows proper caching
to take place.

References: #12314

[postgresql] [usecase] [asyncio] Added an additional asyncio.shield() call within the connection
terminate process of the asyncpg driver, to mitigate an issue where
terminate would be prevented from completing under the anyio concurrency
library.

References: #12077
[postgresql] [bug] Adjusted the asyncpg connection wrapper so that the
connection.transaction() call sent to asyncpg sends None for
isolation_level if not otherwise set in the SQLAlchemy dialect/wrapper,
thereby allowing asyncpg to make use of the server level setting for
isolation_level in the absense of a client-level setting. Previously,
this behavior of asyncpg was blocked by a hardcoded read_committed.

References: #12159

[mariadb] [bug] [dml] [mysql] Fixed a bug where the MySQL statement compiler would not properly compile
statements where _mysql.Insert.on_duplicate_key_update() was passed
values that included ORM-mapped attributes (e.g.
InstrumentedAttribute objects) as keys. Pull request courtesy of
mingyu.

References: #12117

[sqlite] [bug] [aiosqlite] [asyncio] [pool] Changed default connection pool used by the aiosqlite dialect
from NullPool to AsyncAdaptedQueuePool; this change
should have been made when 2.0 was first released as the pysqlite
dialect was similarly changed to use QueuePool as detailed
in change_7490.

References: #12285