1.4.10

Released: April 20, 2021

orm

• [orm] [usecase] Altered some of the behavior repaired in #6232 where the
  immediateload loader strategy no longer goes into recursive loops; the
  modification is that an eager load (joinedload, selectinload, or
  subqueryload) from A->bs->B which then states immediateload for a
  simple manytoone B->a->A that's in the identity map will populate the B->A,
  so that this attribute is back-populated when the collection of A/A.bs are
  loaded. This allows the objects to be functional when detached.

• [orm] [bug] Fixed bug in new _orm.with_loader_criteria() feature where using a
  mixin class with _orm.declared_attr() on an attribute that were
  accessed inside the custom lambda would emit a warning regarding using an
  unmapped declared attr, when the lambda callable were first initialized.
  This warning is now prevented using special instrumentation for this
  lambda initialization step.

  References: #6320

• [orm] [bug] [regression] Fixed additional regression caused by the "eagerloaders on refresh" feature
  added in #1763 where the refresh operation historically would set
  populate_existing, which given the new feature now overwrites pending
  changes on eagerly loaded objects when autoflush is false. The
  populate_existing flag has been turned off for this case and a more
  specific method used to ensure the correct attributes refreshed.

  References: #6326

• [orm] [bug] [result] Fixed an issue when using 2.0 style execution that prevented using
  _result.Result.scalar_one() or
  _result.Result.scalar_one_or_none() after calling
  _result.Result.unique(), for the case where the ORM is returning a
  single-element row in any case.

  References: #6299

sql

• [sql] [bug] Fixed issue in SQL compiler where the bound parameters set up for a
  Values construct wouldn't be positionally tracked correctly if
  inside of a _sql.CTE, affecting database drivers that support
  VALUES + ctes and use positional parameters such as SQL Server in
  particular as well as asyncpg. The fix also repairs support for
  compiler flags such as literal_binds.

  References: #6327

• [sql] [bug] Repaired and solidified issues regarding custom functions and other
  arbitrary expression constructs which within SQLAlchemy's column labeling
  mechanics would seek to use str(obj) to get a string representation to
  use as an anonymous column name in the .c collection of a subquery.
  This is a very legacy behavior that performs poorly and leads to lots of
  issues, so has been revised to no longer perform any compilation by
  establishing specific methods on FunctionElement to handle this
  case, as SQL functions are the only use case that it came into play. An
  effect of this behavior is that an unlabeled column expression with no
  derivable name will be given an arbitrary label starting with the prefix
  "_no_label" in the .c collection of a subquery; these were
  previously being represented either as the generic stringification of that
  expression, or as an internal symbol.

  References: #6256

schema

• [schema] [usecase] [mssql] The _types.DateTime.timezone parameter when set to True
  will now make use of the DATETIMEOFFSET column type with SQL Server
  when used to emit DDL, rather than DATETIME where the flag was silently
  ignored.

  References: #6306

• [schema] [bug] Fixed issue where _functions.next_value() was not deriving its type
  from the corresponding _schema.Sequence, instead hardcoded to
  _types.Integer. The specific numeric type is now used.

  References: #6287

mypy

• [mypy] [bug] Fixed issue where mypy plugin would not correctly interpret an explicit
  _orm.Mapped annotation in conjunction with a
  _orm.relationship() that refers to a class by string name; the
  correct annotation would be downgraded to a less specific one leading to
  typing errors.

  References: #6255

misc

• [bug] [declarative] [regression] Fixed _declarative.instrument_declarative() that called
  a non existing registry method.

  References: #6291