1.4.30

Released: January 19, 2022

orm

• [orm] [bug] Fixed issue in joined-inheritance load of additional attributes
  functionality in deep multi-level inheritance where an intermediary table
  that contained no columns would not be included in the tables joined,
  instead linking those tables to their primary key identifiers. While this
  works fine, it nonetheless in 1.4 began producing the cartesian product
  compiler warning. The logic has been changed so that these intermediary
  tables are included regardless. While this does include additional tables
  in the query that are not technically necessary, this only occurs for the
  highly unusual case of deep 3+ level inheritance with intermediary tables
  that have no non primary key columns, potential performance impact is
  therefore expected to be negligible.

  References: #7507

• [orm] [bug] Fixed issue where calling upon _orm.registry.map_imperatively() more
  than once for the same class would produce an unexpected error, rather than
  an informative error that the target class is already mapped. This behavior
  differed from that of the _orm.mapper() function which does report an
  informative message already.

  References: #7579

• [orm] [bug] [asyncio] Added missing method _asyncio.AsyncSession.invalidate() to the
  _asyncio.AsyncSession class.

  References: #7524

• [orm] [bug] [regression] Fixed regression which appeared in 1.4.23 which could cause loader options
  to be mis-handled in some cases, in particular when using joined table
  inheritance in combination with the polymorphic_load="selectin" option
  as well as relationship lazy loading, leading to a TypeError.

  References: #7557

• [orm] [bug] [regression] Fixed ORM regression where calling the _orm.aliased() function
  against an existing _orm.aliased() construct would fail to produce
  correct SQL if the existing construct were against a fixed table. The fix
  allows that the original _orm.aliased() construct is disregarded if
  it were only against a table that's now being replaced. It also allows for
  correct behavior when constructing a _orm.aliased() without a
  selectable argument against a _orm.aliased() that's against a
  subuquery, to create an alias of that subquery (i.e. to change its name).

  The nesting behavior of _orm.aliased() remains in place for the case
  where the outer _orm.aliased() object is against a subquery which in
  turn refers to the inner _orm.aliased() object. This is a relatively
  new 1.4 feature that helps to suit use cases that were previously served by
  the deprecated Query.from_self() method.

  References: #7576

• [orm] [bug] Fixed issue where _sql.Select.correlate_except() method, when passed
  either the None value or no arguments, would not correlate any elements
  when used in an ORM context (that is, passing ORM entities as FROM
  clauses), rather than causing all FROM elements to be considered as
  "correlated" in the same way which occurs when using Core-only constructs.

  References: #7514

• [orm] [bug] [regression] Fixed regression from 1.3 where the "subqueryload" loader strategy would
  fail with a stack trace if used against a query that made use of
  _orm.Query.from_statement() or _sql.Select.from_statement(). As
  subqueryload requires modifying the original statement, it's not compatible
  with the "from_statement" use case, especially for statements made against
  the _sql.text() construct. The behavior now is equivalent to that of
  1.3 and previously, which is that the loader strategy silently degrades to
  not be used for such statements, typically falling back to using the
  lazyload strategy.

  References: #7505

sql

• [sql] [bug] [postgresql] Added additional rule to the system that determines TypeEngine
  implementations from Python literals to apply a second level of adjustment
  to the type, so that a Python datetime with or without tzinfo can set the
  timezone=True parameter on the returned DateTime object, as
  well as Time. This helps with some round-trip scenarios on
  type-sensitive PostgreSQL dialects such as asyncpg, psycopg3 (2.0 only).

  References: #7537

• [sql] [bug] Added an informative error message when a method object is passed to a SQL
  construct. Previously, when such a callable were passed, as is a common
  typographical error when dealing with method-chained SQL constructs, they
  were interpreted as "lambda SQL" targets to be invoked at compilation time,
  which would lead to silent failures. As this feature was not intended to be
  used with methods, method objects are now rejected.

  References: #7032

mypy

• [mypy] [bug] Fixed Mypy crash when running id daemon mode caused by a
  missing attribute on an internal mypy Var instance.

  References: #7321

asyncio

• [asyncio] [usecase] Added new method AdaptedConnection.run_async() to the DBAPI
  connection interface used by asyncio drivers, which allows methods to be
  called against the underlying "driver" connection directly within a
  sync-style function where the await keyword can't be used, such as
  within SQLAlchemy event handler functions. The method is analogous to the
  _asyncio.AsyncConnection.run_sync() method which translates
  async-style calls to sync-style. The method is useful for things like
  connection-pool on-connect handlers that need to invoke awaitable methods
  on the driver connection when it's first created.

  References: #7580

postgresql

• [postgresql] [usecase] Added string rendering to the postgresql.UUID datatype, so that
  stringifying a statement with "literal_binds" that uses this type will
  render an appropriate string value for the PostgreSQL backend. Pull request
  courtesy José Duarte.

  References: #7561

• [postgresql] [bug] [asyncpg] Improved support for asyncpg handling of TIME WITH TIMEZONE, which
  was not fully implemented.

  References: #7537

• [postgresql] [bug] [mssql] [reflection] Fixed reflection of covering indexes to report include_columns as part
  of the dialect_options entry in the reflected index dictionary, thereby
  enabling round trips from reflection->create to be complete. Included
  columns continue to also be present under the include_columns key for
  backwards compatibility.

  References: #7382

• [postgresql] [bug] Fixed handling of array of enum values which require escape characters.

  References: #7418

mysql

• [mysql] [change] Replace SHOW VARIABLES LIKE statement with equivalent
  SELECT @@variable in MySQL and MariaDB dialect initialization.
  This should avoid mutex contention caused by SHOW VARIABLES,
  improving initialization performance.

  References: #7518

• [mysql] [bug] Removed unnecessary dependency on PyMySQL from the asyncmy dialect. Pull
  request courtesy long2ice.

  References: #7567