2.0.14

Released: May 18, 2023

orm

• [orm] [bug] Modified the JoinedLoader implementation to use a simpler approach in
  one particular area where it previously used a cached structure that would
  be shared among threads. The rationale is to avoid a potential race
  condition which is suspected of being the cause of a particular crash
  that's been reported multiple times. The cached structure in question is
  still ultimately "cached" via the compiled SQL cache, so a performance
  degradation is not anticipated.

  References: #9777

• [orm] [bug] [regression] Fixed regression where use of _dml.update() or _dml.delete()
  within a _sql.CTE construct, then used in a _sql.select(),
  would raise a CompileError as a result of ORM related rules for
  performing ORM-level update/delete statements.

  References: #9767

• [orm] [bug] Fixed issue in new ORM Annotated Declarative where using a
  _schema.ForeignKey (or other column-level constraint) inside of
  _orm.mapped_column() which is then copied out to models via pep-593
  Annotated would apply duplicates of each constraint to the
  _schema.Column as produced in the target _schema.Table,
  leading to incorrect CREATE TABLE DDL as well as migration directives under
  Alembic.

  References: #9766

• [orm] [bug] Fixed issue where using additional relationship criteria with the
  _orm.joinedload() loader option, where the additional criteria itself
  contained correlated subqueries that referred to the joined entities and
  therefore also required "adaption" to aliased entities, would be excluded
  from this adaption, producing the wrong ON clause for the joinedload.

  References: #9779

sql

• [sql] [usecase] Generalized the MSSQL _sql.try_cast() function into the
  sqlalchemy. import namespace so that it may be implemented by third
  party dialects as well. Within SQLAlchemy, the _sql.try_cast()
  function remains a SQL Server-only construct that will raise
  CompileError if used with backends that don't support it.

  _sql.try_cast() implements a CAST where un-castable conversions are
  returned as NULL, instead of raising an error. Theoretically, the construct
  could be implemented by third party dialects for Google BigQuery, DuckDB,
  and Snowflake, and possibly others.

  Pull request courtesy Nick Crews.

  References: #9752

• [sql] [bug] Fixed issue in _sql.values() construct where an internal compilation
  error would occur if the construct were used inside of a scalar subquery.

  References: #9772

postgresql

• [postgresql] [bug] Fixed apparently very old issue where the
  _postgresql.ENUM.create_type parameter, when set to its
  non-default of False, would not be propagated when the
  _schema.Column which it's a part of were copied, as is common when
  using ORM Declarative mixins.

  References: #9773

tests

• [tests] [bug] [pypy] Fixed test that relied on the sys.getsizeof() function to not run on
  pypy, where this function appears to have different behavior than it does
  on cpython.

  References: #9789