2.1.0rc2

Released: September 8, 2026

orm

• [orm] [usecase] The collection of per-mapper / per-table binds established by the
  _orm.Session.binds parameter, as well as by the
  _orm.Session.bind_mapper() and _orm.Session.bind_table()
  methods, is now available publicly as _orm.Session.binds; the
  collection was previously stored under a private, name-mangled attribute.
  It is an immutable dictionary, and is replaced rather than mutated when a
  new bind is added, so a reference to it will not observe subsequent
  changes. The collection is also proxied by
  _orm.scoping.scoped_session.

  References: #13563

• [orm] [bug] Fixed issue where an expression passed to _orm.with_expression()
  that embedded a _sql.select(), such as a correlated
  _sql.exists(), would fail to populate the attribute correctly on
  the second and subsequent executions of an otherwise identical
  statement, when the _orm.query_expression() attribute was loaded
  by a relationship loader that emits a second query, i.e.
  _orm.selectinload(), _orm.lazyload() or
  _orm.immediateload().

  This change is also backported to: 2.0.53

  References: #13560

• [orm] [bug] Fixed memory issue where mapped classes, along with their
  Table and _orm.Mapper objects, would not be garbage
  collected after the _orm.registry in which they were mapped had
  been disposed and dereferenced. The issue would occur for mappings that
  made use of _orm.relationship() together with constructs such as an
  Index established against an ORM-annotated expression.

  This change is also backported to: 2.0.53

  References: #13566

orm declarative

• [bug] [orm declarative] Fixed memory issue where a declarative class making use of the
  __declare_first__() or __declare_last__() hooks could never be
  garbage collected, as each such class established its own permanent
  _orm.Mapper-wide event listener referring to it. These hooks
  are now invoked by _orm.registry-local RegistryEvents
  listeners which refer to the classes weakly, and which are invoked only
  for the _orm.registry being configured. As the hooks are now
  located as the class is added to the _orm.registry, they also
  take effect for classes mapped using
  _orm.registry.map_imperatively().

  References: #9147

engine

• [engine] [changed] Improved the implementation of _pool.Pool to use
  weakref.finalize() instead of a weakref.ref() finalizer to handle
  GC cleanup of non-detached, pooled connections that were not explicitly
  closed.

asyncio

• [asyncio] [usecase] _asyncio.AsyncSession.bind and
  _asyncio.AsyncSession.binds are now always present and are
  derived from the underlying _asyncio.AsyncSession.sync_session,
  translated back into their asyncio equivalents. Added
  _asyncio.AsyncSession.get_async_bind(),
  _asyncio.AsyncSession.bind_mapper() and
  _asyncio.AsyncSession.bind_table() as the asyncio-facing
  counterparts to the _orm.Session methods of the same name.
  Both attributes, along with
  _asyncio.AsyncSession.get_async_bind(), are proxied by
  _asyncio.async_scoped_session.

  References: #13563

sqlite

• [sqlite] [usecase] [reflection] Implemented _engine.Inspector.get_table_options() for the SQLite
  dialect, which previously raised NotImplementedError. The method
  returns the sqlite_with_rowid and sqlite_strict dialect options
  for a table that was created using the WITHOUT ROWID and / or
  STRICT keywords. As a result, these keywords are now also present in
  _schema.Table.kwargs for a _schema.Table that is
  reflected using autoload, so that a table which is recreated from its
  reflected form, such as by Alembic's batch migration mode, renders the
  keywords again rather than silently dropping them.

  This change is also backported to: 2.0.53

  References: #13543

• [sqlite] [bug] [reflection] Reworked the regular expression that parses FOREIGN KEY constraints
  during SQLite CREATE TABLE reflection so that the referred column list
  is matched unambiguously avoiding potential exponential backtracking.
  Pull request courtesy of Javid Khan.

  This change is also backported to: 2.0.53

  References: #13530