2.0.22

Released: October 12, 2023

orm

• [orm] [usecase] Added method _orm.Session.get_one() that behaves like
  _orm.Session.get() but raises an exception instead of returning
  None if no instance was found with the provided primary key.
  Pull request courtesy of Carlos Sousa.

  References: #10202

• [orm] [usecase] Added an option to permanently close sessions.
  Set to False the new parameter _orm.Session.close_resets_only
  will prevent a _orm.Session from performing any other
  operation after _orm.Session.close() has been called.

  Added new method _orm.Session.reset() that will reset a _orm.Session
  to its initial state. This is an alias of _orm.Session.close(),
  unless _orm.Session.close_resets_only is set to False.

  References: #7787

• [orm] [bug] Fixed a wide range of _orm.mapped_column() parameters that were not
  being transferred when using the _orm.mapped_column() object inside
  of a pep-593 Annotated object, including
  _orm.mapped_column.sort_order,
  _orm.mapped_column.deferred,
  _orm.mapped_column.autoincrement,
  _orm.mapped_column.system, _orm.mapped_column.info
  etc.

  Additionally, it remains not supported to have dataclass arguments, such as
  _orm.mapped_column.kw_only,
  _orm.mapped_column.default_factory etc. indicated within the
  _orm.mapped_column() received by Annotated, as this is not
  supported with pep-681 Dataclass Transforms. A warning is now emitted when
  these parameters are used within Annotated in this way (and they
  continue to be ignored).

  References: #10046, #10369

• [orm] [bug] Fixed issue where calling _engine.Result.unique() with a new-style
  select() query in the ORM, where one or more columns yields values
  that are of "unknown hashability", typically when using JSON functions like
  func.json_build_object() without providing a type, would fail
  internally when the returned values were not actually hashable. The
  behavior is repaired to test the objects as they are received for
  hashability in this case, raising an informative error message if not. Note
  that for values of "known unhashability", such as when the
  _types.JSON or _types.ARRAY types are used directly, an
  informative error message was already raised.

  The "hashabiltiy testing" fix here is applied to legacy Query as
  well, however in the legacy case, _engine.Result.unique() is used for
  nearly all queries, so no new warning is emitted here; the legacy behavior
  of falling back to using id() in this case is maintained, with the
  improvement that an unknown type that turns out to be hashable will now be
  uniqufied, whereas previously it would not.

  References: #10459

• [orm] [bug] Fixed regression in recently revised "insertmanyvalues" feature (likely
  issue #9618) where the ORM would inadvertently attempt to
  interpret a non-RETURNING result as one with RETURNING, in the case where
  the implicit_returning=False parameter were applied to the mapped
  Table, indicating that "insertmanyvalues" cannot be used if the
  primary key values are not provided.

  References: #10453

• [orm] [bug] Fixed bug where ORM _orm.with_loader_criteria() would not apply
  itself to a _sql.Select.join() where the ON clause were given as a
  plain SQL comparison, rather than as a relationship target or similar.

  References: #10365

• [orm] [bug] Fixed issue where Mapped symbols like WriteOnlyMapped
  and DynamicMapped could not be correctly resolved when referenced
  as an element of a sub-module in the given annotation, assuming
  string-based or "future annotations" style annotations.

  References: #10412

• [orm] [bug] Fixed issue with __allow_unmapped__ declarative option
  where types that were declared using collection types such as
  list[SomeClass] vs. the typing construct List[SomeClass]
  would fail to be recognized correctly. Pull request courtesy
  Pascal Corpet.

  References: #10385

engine

• [engine] [bug] Fixed issue within some dialects where the dialect could incorrectly return
  an empty result set for an INSERT statement that does not actually return
  rows at all, due to artfacts from pre- or post-fetching the primary key of
  the row or rows still being present. Affected dialects included asyncpg,
  all mssql dialects.

• [engine] [bug] Fixed issue where under some garbage collection / exception scenarios the
  connection pool's cleanup routine would raise an error due to an unexpected
  set of state, which can be reproduced under specific conditions.

  References: #10414

sql

• [sql] [bug] Fixed issue where referring to a FROM entry in the SET clause of an UPDATE
  statement would not include it in the FROM clause of the UPDATE statement,
  if that entry were nowhere else in the statement; this occurs currently for
  CTEs that were added using Update.add_cte() to provide the desired
  CTE at the top of the statement.

  References: #10408

• [sql] [bug] Fixed 2.0 regression where the DDL construct would no longer
  __repr__() due to the removed on attribute not being accommodated.
  Pull request courtesy Iuri de Silvio.

  References: #10443

typing

• [typing] [bug] Fixed typing issue where the argument list passed to Values was
  too-restrictively tied to List rather than Sequence. Pull request
  courtesy Iuri de Silvio.

  References: #10451

• [typing] [bug] Updates to the codebase to support Mypy 1.6.0.

asyncio

• [asyncio] [bug] Fixed the _asyncio.AsyncSession.get.execution_options parameter
  which was not being propagated to the underlying _orm.Session and
  was instead being ignored.

mariadb

• [mariadb] [bug] Modified the mariadb-connector driver to pre-load the cursor.rowcount
  value for all queries, to suit tools such as Pandas that hardcode to
  calling Result.rowcount in this way. SQLAlchemy normally pre-loads
  cursor.rowcount only for UPDATE/DELETE statements and otherwise passes
  through to the DBAPI where it can return -1 if no value is available.
  However, mariadb-connector does not support invoking cursor.rowcount
  after the cursor itself is closed, raising an error instead. Generic test
  support has been added to ensure all backends support the allowing
  Result.rowcount to succceed (that is, returning an integer
  value with -1 for "not available") after the result is closed.

  References: #10396

• [mariadb] [bug] Additional fixes for the mariadb-connector dialect to support UUID data
  values in the result in INSERT..RETURNING statements.

mssql

• [mssql] [bug] Fixed bug where the rule that prevents ORDER BY from emitting within
  subqueries on SQL Server was not being disabled in the case where the
  select.fetch() method were used to limit rows in conjunction with
  WITH TIES or PERCENT, preventing valid subqueries with TOP / ORDER BY from
  being used.

  References: #10458