# SQLAlchemy rel_2_0_52 — 2.0.52

- Product: SQLAlchemy (https://whatsnew.fyi/product/sqlalchemy)
- Vendor: SQLAlchemy
- Date: 2026-08-11
- Version: rel_2_0_52
- Original notes: https://github.com/sqlalchemy/sqlalchemy/releases/tag/rel_2_0_52
- Permalink: https://whatsnew.fyi/product/sqlalchemy/releases/rel-2-0-52

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- **added** — Python 3.15 support has been added and tested with minimal changes for full compatibility
- **fixed** — Fixed a result-column misalignment bug in ORM-enabled UPDATE statements where synchronize_session="fetch" is in use, where columns in rows returned by .returning() could be returned under incorrect keys
- **fixed** — Fixed bug where a failed bulk_insert_mappings(), bulk_update_mappings() or bulk_save_objects() call could leave the Session permanently in a flushing state
- **fixed** — Fixed issue where unpickling an ORM object loaded using loader options with wildcard tokens would fail with KeyError or IndexError in separate processes
- **fixed** — Fixed issue where a string ending in "*" passed to a Load strategy method would bypass the check rejecting string attribute names and now raises ArgumentError
- **fixed** — Calling aliased() against a select() or union() / CompoundSelect construct now raises under SQLAlchemy 2.1 and emits a deprecation warning under SQLAlchemy 2.0
- **fixed** — Fixed issue where using PEP 593 Annotated wrapping a PEP 695 type alias would crash with AttributeError: __value__
- **fixed** — Fixed issue where Select.get_final_froms() would emit a spurious deprecation warning when the statement used the PostgreSQL-specific expression argument to Select.distinct()
- **fixed** — Fixed an issue in Numeric where the decimal_return_scale parameter was ignored when the DBAPI does not support native decimal objects

#### 2.0.52

Released: August 11, 2026
##### platform


-   **[platform] [bug]** Python 3.15 support has been added and tested, including minimal changes
    for full compatibility.
    
    References: [#13477](https://www.sqlalchemy.org/trac/ticket/13477)

##### orm


-   **[orm] [bug]** Fixed a result-column misalignment bug in ORM-enabled UPDATE statements
    where `synchronize_session="fetch"` is in use, either explicitly or
    because the statement uses constructs such as CTEs that implicitly select
    for it.  Columns in rows returned by `.returning()` could be returned
    under incorrect keys (e.g. `row[SomeClass.a]` returning the value of
    a different column), a problem most likely to manifest under concurrent
    workloads.  ORM DELETE statements were not affected.
    
    References: [#13439](https://www.sqlalchemy.org/trac/ticket/13439)

-   **[orm] [bug]** Fixed bug where a failed `_orm.Session.bulk_insert_mappings()`,
    `_orm.Session.bulk_update_mappings()` or
    `_orm.Session.bulk_save_objects()` call could leave the
    `_orm.Session` permanently in a "flushing" state, such as when the
    transaction could not be begun because a previous flush had left it
    needing a rollback.  Unlike `_orm.Session.flush()`, the bulk methods
    set the internal flushing flag and began the transaction outside of the
    `try`/`finally` block that resets it, so that neither
    `_orm.Session.rollback()` nor `_orm.Session.close()` would clear
    it, and every subsequent flush would raise `InvalidRequestError: Session
    is already flushing`.  Pull request courtesy Hamody We.
    
    References: [#13485](https://www.sqlalchemy.org/trac/ticket/13485)

-   **[orm] [bug]** Fixed issue where unpickling an ORM object that were loaded using loader
    options making use of wildcard tokens, such as `_orm.load_only()` or
    `_orm.raiseload()` with `"*"`, would fail with `KeyError` or
    `IndexError` if the process doing the unpickling had not yet constructed
    a loader path making use of that same token.  This would typically be
    observed when the object were unpickled in a separate process, such as
    with the `spawn` or `forkserver` multiprocessing start methods, the
    latter of which became the default on POSIX platforms as of Python 3.14.
    The internal collection of these tokens is now established up front, so
    that it is identical in every process.
    
    References: [#13493](https://www.sqlalchemy.org/trac/ticket/13493)

-   **[orm] [bug]** Fixed issue where a string ending in `"*"` passed to a
    `_orm.Load` strategy method, such as
    `Load(A).joinedload("bs.*")`, would bypass the check which rejects
    string attribute names in loader options, silently producing a loader
    path that matched nothing.  Such a string now raises
    `ArgumentError` with the same message given for any other
    string attribute name.  The bare wildcard `"*"`, as in
    `Load(A).lazyload("*")`, continues to be accepted.
    
    References: [#13493](https://www.sqlalchemy.org/trac/ticket/13493)

-   **[orm] [bug]** Calling `_orm.aliased()` against a `_sql.select()` or
    `_sql.union()` / `_sql.CompoundSelect` construct, which
    previously failed with an obscure `AttributeError` regarding a missing
    `.mapper` attribute, now raises when using SQLAlchemy 2.1, and emits a
    deprecation warning under SQLAlchemy 2.0 as it coerces the construct into a
    subquery instead.  This matches the behavior of other similar implicit
    SELECT-to-FROM coercions.  Pull request courtesy Rens Groothuijsen.
    
    References: [#6274](https://www.sqlalchemy.org/trac/ticket/6274)

##### orm declarative


-   **[bug] [orm declarative]** Fixed issue where using [PEP 593](https://peps.python.org/pep-0593) `Annotated` wrapping a [PEP 695](https://peps.python.org/pep-0695)
    `type` alias, such as `Annotated[SomeTypeAlias, mapped_column()]`,
    would crash with `AttributeError: __value__`. The internal
    `is_pep695()` check

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