Current File : //opt/hc_python/lib64/python3.8/site-packages/sqlalchemy/orm/strategy_options.py
# orm/strategy_options.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: allow-untyped-defs, allow-untyped-calls
"""
"""
from __future__ import annotations
import typing
from typing import Any
from typing import Callable
from typing import cast
from typing import Dict
from typing import Iterable
from typing import Optional
from typing import overload
from typing import Sequence
from typing import Tuple
from typing import Type
from typing import TypeVar
from typing import Union
from . import util as orm_util
from ._typing import insp_is_aliased_class
from ._typing import insp_is_attribute
from ._typing import insp_is_mapper
from ._typing import insp_is_mapper_property
from .attributes import QueryableAttribute
from .base import InspectionAttr
from .interfaces import LoaderOption
from .path_registry import _DEFAULT_TOKEN
from .path_registry import _StrPathToken
from .path_registry import _WILDCARD_TOKEN
from .path_registry import AbstractEntityRegistry
from .path_registry import path_is_property
from .path_registry import PathRegistry
from .path_registry import TokenRegistry
from .util import _orm_full_deannotate
from .util import AliasedInsp
from .. import exc as sa_exc
from .. import inspect
from .. import util
from ..sql import and_
from ..sql import cache_key
from ..sql import coercions
from ..sql import roles
from ..sql import traversals
from ..sql import visitors
from ..sql.base import _generative
from ..util.typing import Final
from ..util.typing import Literal
from ..util.typing import Self
_RELATIONSHIP_TOKEN: Final[Literal["relationship"]] = "relationship"
_COLUMN_TOKEN: Final[Literal["column"]] = "column"
_FN = TypeVar("_FN", bound="Callable[..., Any]")
if typing.TYPE_CHECKING:
from ._typing import _EntityType
from ._typing import _InternalEntityType
from .context import _MapperEntity
from .context import ORMCompileState
from .context import QueryContext
from .interfaces import _StrategyKey
from .interfaces import MapperProperty
from .interfaces import ORMOption
from .mapper import Mapper
from .path_registry import _PathRepresentation
from ..sql._typing import _ColumnExpressionArgument
from ..sql._typing import _FromClauseArgument
from ..sql.cache_key import _CacheKeyTraversalType
from ..sql.cache_key import CacheKey
_AttrType = Union[Literal["*"], "QueryableAttribute[Any]"]
_WildcardKeyType = Literal["relationship", "column"]
_StrategySpec = Dict[str, Any]
_OptsType = Dict[str, Any]
_AttrGroupType = Tuple[_AttrType, ...]
class _AbstractLoad(traversals.GenerativeOnTraversal, LoaderOption):
__slots__ = ("propagate_to_loaders",)
_is_strategy_option = True
propagate_to_loaders: bool
def contains_eager(
self,
attr: _AttrType,
alias: Optional[_FromClauseArgument] = None,
_is_chain: bool = False,
_propagate_to_loaders: bool = False,
) -> Self:
r"""Indicate that the given attribute should be eagerly loaded from
columns stated manually in the query.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
The option is used in conjunction with an explicit join that loads
the desired rows, i.e.::
sess.query(Order).join(Order.user).options(
contains_eager(Order.user)
)
The above query would join from the ``Order`` entity to its related
``User`` entity, and the returned ``Order`` objects would have the
``Order.user`` attribute pre-populated.
It may also be used for customizing the entries in an eagerly loaded
collection; queries will normally want to use the
:ref:`orm_queryguide_populate_existing` execution option assuming the
primary collection of parent objects may already have been loaded::
sess.query(User).join(User.addresses).filter(
Address.email_address.like("%@aol.com")
).options(contains_eager(User.addresses)).populate_existing()
See the section :ref:`contains_eager` for complete usage details.
.. seealso::
:ref:`loading_toplevel`
:ref:`contains_eager`
"""
if alias is not None:
if not isinstance(alias, str):
coerced_alias = coercions.expect(roles.FromClauseRole, alias)
else:
util.warn_deprecated(
"Passing a string name for the 'alias' argument to "
"'contains_eager()` is deprecated, and will not work in a "
"future release. Please use a sqlalchemy.alias() or "
"sqlalchemy.orm.aliased() construct.",
version="1.4",
)
coerced_alias = alias
elif getattr(attr, "_of_type", None):
assert isinstance(attr, QueryableAttribute)
ot: Optional[_InternalEntityType[Any]] = inspect(attr._of_type)
assert ot is not None
coerced_alias = ot.selectable
else:
coerced_alias = None
cloned = self._set_relationship_strategy(
attr,
{"lazy": "joined"},
propagate_to_loaders=_propagate_to_loaders,
opts={"eager_from_alias": coerced_alias},
_reconcile_to_other=True if _is_chain else None,
)
return cloned
def load_only(self, *attrs: _AttrType, raiseload: bool = False) -> Self:
r"""Indicate that for a particular entity, only the given list
of column-based attribute names should be loaded; all others will be
deferred.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
Example - given a class ``User``, load only the ``name`` and
``fullname`` attributes::
session.query(User).options(load_only(User.name, User.fullname))
Example - given a relationship ``User.addresses -> Address``, specify
subquery loading for the ``User.addresses`` collection, but on each
``Address`` object load only the ``email_address`` attribute::
session.query(User).options(
subqueryload(User.addresses).load_only(Address.email_address)
)
For a statement that has multiple entities,
the lead entity can be
specifically referred to using the :class:`_orm.Load` constructor::
stmt = (
select(User, Address)
.join(User.addresses)
.options(
Load(User).load_only(User.name, User.fullname),
Load(Address).load_only(Address.email_address),
)
)
When used together with the
:ref:`populate_existing <orm_queryguide_populate_existing>`
execution option only the attributes listed will be refreshed.
:param \*attrs: Attributes to be loaded, all others will be deferred.
:param raiseload: raise :class:`.InvalidRequestError` rather than
lazy loading a value when a deferred attribute is accessed. Used
to prevent unwanted SQL from being emitted.
.. versionadded:: 2.0
.. seealso::
:ref:`orm_queryguide_column_deferral` - in the
:ref:`queryguide_toplevel`
:param \*attrs: Attributes to be loaded, all others will be deferred.
:param raiseload: raise :class:`.InvalidRequestError` rather than
lazy loading a value when a deferred attribute is accessed. Used
to prevent unwanted SQL from being emitted.
.. versionadded:: 2.0
"""
cloned = self._set_column_strategy(
attrs,
{"deferred": False, "instrument": True},
)
wildcard_strategy = {"deferred": True, "instrument": True}
if raiseload:
wildcard_strategy["raiseload"] = True
cloned = cloned._set_column_strategy(
("*",),
wildcard_strategy,
)
return cloned
def joinedload(
self,
attr: _AttrType,
innerjoin: Optional[bool] = None,
) -> Self:
"""Indicate that the given attribute should be loaded using joined
eager loading.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
examples::
# joined-load the "orders" collection on "User"
select(User).options(joinedload(User.orders))
# joined-load Order.items and then Item.keywords
select(Order).options(
joinedload(Order.items).joinedload(Item.keywords)
)
# lazily load Order.items, but when Items are loaded,
# joined-load the keywords collection
select(Order).options(
lazyload(Order.items).joinedload(Item.keywords)
)
:param innerjoin: if ``True``, indicates that the joined eager load
should use an inner join instead of the default of left outer join::
select(Order).options(joinedload(Order.user, innerjoin=True))
In order to chain multiple eager joins together where some may be
OUTER and others INNER, right-nested joins are used to link them::
select(A).options(
joinedload(A.bs, innerjoin=False).joinedload(
B.cs, innerjoin=True
)
)
The above query, linking A.bs via "outer" join and B.cs via "inner"
join would render the joins as "a LEFT OUTER JOIN (b JOIN c)". When
using older versions of SQLite (< 3.7.16), this form of JOIN is
translated to use full subqueries as this syntax is otherwise not
directly supported.
The ``innerjoin`` flag can also be stated with the term ``"unnested"``.
This indicates that an INNER JOIN should be used, *unless* the join
is linked to a LEFT OUTER JOIN to the left, in which case it
will render as LEFT OUTER JOIN. For example, supposing ``A.bs``
is an outerjoin::
select(A).options(
joinedload(A.bs).joinedload(B.cs, innerjoin="unnested")
)
The above join will render as "a LEFT OUTER JOIN b LEFT OUTER JOIN c",
rather than as "a LEFT OUTER JOIN (b JOIN c)".
.. note:: The "unnested" flag does **not** affect the JOIN rendered
from a many-to-many association table, e.g. a table configured as
:paramref:`_orm.relationship.secondary`, to the target table; for
correctness of results, these joins are always INNER and are
therefore right-nested if linked to an OUTER join.
.. note::
The joins produced by :func:`_orm.joinedload` are **anonymously
aliased**. The criteria by which the join proceeds cannot be
modified, nor can the ORM-enabled :class:`_sql.Select` or legacy
:class:`_query.Query` refer to these joins in any way, including
ordering. See :ref:`zen_of_eager_loading` for further detail.
To produce a specific SQL JOIN which is explicitly available, use
:meth:`_sql.Select.join` and :meth:`_query.Query.join`. To combine
explicit JOINs with eager loading of collections, use
:func:`_orm.contains_eager`; see :ref:`contains_eager`.
.. seealso::
:ref:`loading_toplevel`
:ref:`joined_eager_loading`
"""
loader = self._set_relationship_strategy(
attr,
{"lazy": "joined"},
opts=(
{"innerjoin": innerjoin}
if innerjoin is not None
else util.EMPTY_DICT
),
)
return loader
def subqueryload(self, attr: _AttrType) -> Self:
"""Indicate that the given attribute should be loaded using
subquery eager loading.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
examples::
# subquery-load the "orders" collection on "User"
select(User).options(subqueryload(User.orders))
# subquery-load Order.items and then Item.keywords
select(Order).options(
subqueryload(Order.items).subqueryload(Item.keywords)
)
# lazily load Order.items, but when Items are loaded,
# subquery-load the keywords collection
select(Order).options(
lazyload(Order.items).subqueryload(Item.keywords)
)
.. seealso::
:ref:`loading_toplevel`
:ref:`subquery_eager_loading`
"""
return self._set_relationship_strategy(attr, {"lazy": "subquery"})
def selectinload(
self,
attr: _AttrType,
recursion_depth: Optional[int] = None,
) -> Self:
"""Indicate that the given attribute should be loaded using
SELECT IN eager loading.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
examples::
# selectin-load the "orders" collection on "User"
select(User).options(selectinload(User.orders))
# selectin-load Order.items and then Item.keywords
select(Order).options(
selectinload(Order.items).selectinload(Item.keywords)
)
# lazily load Order.items, but when Items are loaded,
# selectin-load the keywords collection
select(Order).options(
lazyload(Order.items).selectinload(Item.keywords)
)
:param recursion_depth: optional int; when set to a positive integer
in conjunction with a self-referential relationship,
indicates "selectin" loading will continue that many levels deep
automatically until no items are found.
.. note:: The :paramref:`_orm.selectinload.recursion_depth` option
currently supports only self-referential relationships. There
is not yet an option to automatically traverse recursive structures
with more than one relationship involved.
Additionally, the :paramref:`_orm.selectinload.recursion_depth`
parameter is new and experimental and should be treated as "alpha"
status for the 2.0 series.
.. versionadded:: 2.0 added
:paramref:`_orm.selectinload.recursion_depth`
.. seealso::
:ref:`loading_toplevel`
:ref:`selectin_eager_loading`
"""
return self._set_relationship_strategy(
attr,
{"lazy": "selectin"},
opts={"recursion_depth": recursion_depth},
)
def lazyload(self, attr: _AttrType) -> Self:
"""Indicate that the given attribute should be loaded using "lazy"
loading.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
.. seealso::
:ref:`loading_toplevel`
:ref:`lazy_loading`
"""
return self._set_relationship_strategy(attr, {"lazy": "select"})
def immediateload(
self,
attr: _AttrType,
recursion_depth: Optional[int] = None,
) -> Self:
"""Indicate that the given attribute should be loaded using
an immediate load with a per-attribute SELECT statement.
The load is achieved using the "lazyloader" strategy and does not
fire off any additional eager loaders.
The :func:`.immediateload` option is superseded in general
by the :func:`.selectinload` option, which performs the same task
more efficiently by emitting a SELECT for all loaded objects.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
:param recursion_depth: optional int; when set to a positive integer
in conjunction with a self-referential relationship,
indicates "selectin" loading will continue that many levels deep
automatically until no items are found.
.. note:: The :paramref:`_orm.immediateload.recursion_depth` option
currently supports only self-referential relationships. There
is not yet an option to automatically traverse recursive structures
with more than one relationship involved.
.. warning:: This parameter is new and experimental and should be
treated as "alpha" status
.. versionadded:: 2.0 added
:paramref:`_orm.immediateload.recursion_depth`
.. seealso::
:ref:`loading_toplevel`
:ref:`selectin_eager_loading`
"""
loader = self._set_relationship_strategy(
attr,
{"lazy": "immediate"},
opts={"recursion_depth": recursion_depth},
)
return loader
def noload(self, attr: _AttrType) -> Self:
"""Indicate that the given relationship attribute should remain
unloaded.
The relationship attribute will return ``None`` when accessed without
producing any loading effect.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
:func:`_orm.noload` applies to :func:`_orm.relationship` attributes
only.
.. legacy:: The :func:`_orm.noload` option is **legacy**. As it
forces collections to be empty, which invariably leads to
non-intuitive and difficult to predict results. There are no
legitimate uses for this option in modern SQLAlchemy.
.. seealso::
:ref:`loading_toplevel`
"""
return self._set_relationship_strategy(attr, {"lazy": "noload"})
def raiseload(self, attr: _AttrType, sql_only: bool = False) -> Self:
"""Indicate that the given attribute should raise an error if accessed.
A relationship attribute configured with :func:`_orm.raiseload` will
raise an :exc:`~sqlalchemy.exc.InvalidRequestError` upon access. The
typical way this is useful is when an application is attempting to
ensure that all relationship attributes that are accessed in a
particular context would have been already loaded via eager loading.
Instead of having to read through SQL logs to ensure lazy loads aren't
occurring, this strategy will cause them to raise immediately.
:func:`_orm.raiseload` applies to :func:`_orm.relationship` attributes
only. In order to apply raise-on-SQL behavior to a column-based
attribute, use the :paramref:`.orm.defer.raiseload` parameter on the
:func:`.defer` loader option.
:param sql_only: if True, raise only if the lazy load would emit SQL,
but not if it is only checking the identity map, or determining that
the related value should just be None due to missing keys. When False,
the strategy will raise for all varieties of relationship loading.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
.. seealso::
:ref:`loading_toplevel`
:ref:`prevent_lazy_with_raiseload`
:ref:`orm_queryguide_deferred_raiseload`
"""
return self._set_relationship_strategy(
attr, {"lazy": "raise_on_sql" if sql_only else "raise"}
)
def defaultload(self, attr: _AttrType) -> Self:
"""Indicate an attribute should load using its predefined loader style.
The behavior of this loading option is to not change the current
loading style of the attribute, meaning that the previously configured
one is used or, if no previous style was selected, the default
loading will be used.
This method is used to link to other loader options further into
a chain of attributes without altering the loader style of the links
along the chain. For example, to set joined eager loading for an
element of an element::
session.query(MyClass).options(
defaultload(MyClass.someattribute).joinedload(
MyOtherClass.someotherattribute
)
)
:func:`.defaultload` is also useful for setting column-level options on
a related class, namely that of :func:`.defer` and :func:`.undefer`::
session.scalars(
select(MyClass).options(
defaultload(MyClass.someattribute)
.defer("some_column")
.undefer("some_other_column")
)
)
.. seealso::
:ref:`orm_queryguide_relationship_sub_options`
:meth:`_orm.Load.options`
"""
return self._set_relationship_strategy(attr, None)
def defer(self, key: _AttrType, raiseload: bool = False) -> Self:
r"""Indicate that the given column-oriented attribute should be
deferred, e.g. not loaded until accessed.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
e.g.::
from sqlalchemy.orm import defer
session.query(MyClass).options(
defer(MyClass.attribute_one),
defer(MyClass.attribute_two)
)
To specify a deferred load of an attribute on a related class,
the path can be specified one token at a time, specifying the loading
style for each link along the chain. To leave the loading style
for a link unchanged, use :func:`_orm.defaultload`::
session.query(MyClass).options(
defaultload(MyClass.someattr).defer(RelatedClass.some_column)
)
Multiple deferral options related to a relationship can be bundled
at once using :meth:`_orm.Load.options`::
select(MyClass).options(
defaultload(MyClass.someattr).options(
defer(RelatedClass.some_column),
defer(RelatedClass.some_other_column),
defer(RelatedClass.another_column)
)
)
:param key: Attribute to be deferred.
:param raiseload: raise :class:`.InvalidRequestError` rather than
lazy loading a value when the deferred attribute is accessed. Used
to prevent unwanted SQL from being emitted.
.. versionadded:: 1.4
.. seealso::
:ref:`orm_queryguide_column_deferral` - in the
:ref:`queryguide_toplevel`
:func:`_orm.load_only`
:func:`_orm.undefer`
"""
strategy = {"deferred": True, "instrument": True}
if raiseload:
strategy["raiseload"] = True
return self._set_column_strategy((key,), strategy)
def undefer(self, key: _AttrType) -> Self:
r"""Indicate that the given column-oriented attribute should be
undeferred, e.g. specified within the SELECT statement of the entity
as a whole.
The column being undeferred is typically set up on the mapping as a
:func:`.deferred` attribute.
This function is part of the :class:`_orm.Load` interface and supports
both method-chained and standalone operation.
Examples::
# undefer two columns
session.query(MyClass).options(
undefer(MyClass.col1), undefer(MyClass.col2)
)
# undefer all columns specific to a single class using Load + *
session.query(MyClass, MyOtherClass).options(
Load(MyClass).undefer("*")
)
# undefer a column on a related object
select(MyClass).options(
defaultload(MyClass.items).undefer(MyClass.text)
)
:param key: Attribute to be undeferred.
.. seealso::
:ref:`orm_queryguide_column_deferral` - in the
:ref:`queryguide_toplevel`
:func:`_orm.defer`
:func:`_orm.undefer_group`
"""
return self._set_column_strategy(
(key,), {"deferred": False, "instrument": True}
)
def undefer_group(self, name: str) -> Self:
"""Indicate that columns within the given deferred group name should be
undeferred.
The columns being undeferred are set up on the mapping as
:func:`.deferred` attributes and include a "group" name.
E.g::
session.query(MyClass).options(undefer_group("large_attrs"))
To undefer a group of attributes on a related entity, the path can be
spelled out using relationship loader options, such as
:func:`_orm.defaultload`::
select(MyClass).options(
defaultload("someattr").undefer_group("large_attrs")
)
.. seealso::
:ref:`orm_queryguide_column_deferral` - in the
:ref:`queryguide_toplevel`
:func:`_orm.defer`
:func:`_orm.undefer`
"""
return self._set_column_strategy(
(_WILDCARD_TOKEN,), None, {f"undefer_group_{name}": True}
)
def with_expression(
self,
key: _AttrType,
expression: _ColumnExpressionArgument[Any],
) -> Self:
r"""Apply an ad-hoc SQL expression to a "deferred expression"
attribute.
This option is used in conjunction with the
:func:`_orm.query_expression` mapper-level construct that indicates an
attribute which should be the target of an ad-hoc SQL expression.
E.g.::
stmt = select(SomeClass).options(
with_expression(SomeClass.x_y_expr, SomeClass.x + SomeClass.y)
)
.. versionadded:: 1.2
:param key: Attribute to be populated
:param expr: SQL expression to be applied to the attribute.
.. seealso::
:ref:`orm_queryguide_with_expression` - background and usage
examples
"""
expression = _orm_full_deannotate(
coercions.expect(roles.LabeledColumnExprRole, expression)
)
return self._set_column_strategy(
(key,), {"query_expression": True}, extra_criteria=(expression,)
)
def selectin_polymorphic(self, classes: Iterable[Type[Any]]) -> Self:
"""Indicate an eager load should take place for all attributes
specific to a subclass.
This uses an additional SELECT with IN against all matched primary
key values, and is the per-query analogue to the ``"selectin"``
setting on the :paramref:`.mapper.polymorphic_load` parameter.
.. versionadded:: 1.2
.. seealso::
:ref:`polymorphic_selectin`
"""
self = self._set_class_strategy(
{"selectinload_polymorphic": True},
opts={
"entities": tuple(
sorted((inspect(cls) for cls in classes), key=id)
)
},
)
return self
@overload
def _coerce_strat(self, strategy: _StrategySpec) -> _StrategyKey: ...
@overload
def _coerce_strat(self, strategy: Literal[None]) -> None: ...
def _coerce_strat(
self, strategy: Optional[_StrategySpec]
) -> Optional[_StrategyKey]:
if strategy is not None:
strategy_key = tuple(sorted(strategy.items()))
else:
strategy_key = None
return strategy_key
@_generative
def _set_relationship_strategy(
self,
attr: _AttrType,
strategy: Optional[_StrategySpec],
propagate_to_loaders: bool = True,
opts: Optional[_OptsType] = None,
_reconcile_to_other: Optional[bool] = None,
) -> Self:
strategy_key = self._coerce_strat(strategy)
self._clone_for_bind_strategy(
(attr,),
strategy_key,
_RELATIONSHIP_TOKEN,
opts=opts,
propagate_to_loaders=propagate_to_loaders,
reconcile_to_other=_reconcile_to_other,
)
return self
@_generative
def _set_column_strategy(
self,
attrs: Tuple[_AttrType, ...],
strategy: Optional[_StrategySpec],
opts: Optional[_OptsType] = None,
extra_criteria: Optional[Tuple[Any, ...]] = None,
) -> Self:
strategy_key = self._coerce_strat(strategy)
self._clone_for_bind_strategy(
attrs,
strategy_key,
_COLUMN_TOKEN,
opts=opts,
attr_group=attrs,
extra_criteria=extra_criteria,
)
return self
@_generative
def _set_generic_strategy(
self,
attrs: Tuple[_AttrType, ...],
strategy: _StrategySpec,
_reconcile_to_other: Optional[bool] = None,
) -> Self:
strategy_key = self._coerce_strat(strategy)
self._clone_for_bind_strategy(
attrs,
strategy_key,
None,
propagate_to_loaders=True,
reconcile_to_other=_reconcile_to_other,
)
return self
@_generative
def _set_class_strategy(
self, strategy: _StrategySpec, opts: _OptsType
) -> Self:
strategy_key = self._coerce_strat(strategy)
self._clone_for_bind_strategy(None, strategy_key, None, opts=opts)
return self
def _apply_to_parent(self, parent: Load) -> None:
"""apply this :class:`_orm._AbstractLoad` object as a sub-option o
a :class:`_orm.Load` object.
Implementation is provided by subclasses.
"""
raise NotImplementedError()
def options(self, *opts: _AbstractLoad) -> Self:
r"""Apply a series of options as sub-options to this
:class:`_orm._AbstractLoad` object.
Implementation is provided by subclasses.
"""
raise NotImplementedError()
def _clone_for_bind_strategy(
self,
attrs: Optional[Tuple[_AttrType, ...]],
strategy: Optional[_StrategyKey],
wildcard_key: Optional[_WildcardKeyType],
opts: Optional[_OptsType] = None,
attr_group: Optional[_AttrGroupType] = None,
propagate_to_loaders: bool = True,
reconcile_to_other: Optional[bool] = None,
extra_criteria: Optional[Tuple[Any, ...]] = None,
) -> Self:
raise NotImplementedError()
def process_compile_state_replaced_entities(
self,
compile_state: ORMCompileState,
mapper_entities: Sequence[_MapperEntity],
) -> None:
if not compile_state.compile_options._enable_eagerloads:
return
# process is being run here so that the options given are validated
# against what the lead entities were, as well as to accommodate
# for the entities having been replaced with equivalents
self._process(
compile_state,
mapper_entities,
not bool(compile_state.current_path),
)
def process_compile_state(self, compile_state: ORMCompileState) -> None:
if not compile_state.compile_options._enable_eagerloads:
return
self._process(
compile_state,
compile_state._lead_mapper_entities,
not bool(compile_state.current_path)
and not compile_state.compile_options._for_refresh_state,
)
def _process(
self,
compile_state: ORMCompileState,
mapper_entities: Sequence[_MapperEntity],
raiseerr: bool,
) -> None:
"""implemented by subclasses"""
raise NotImplementedError()
@classmethod
def _chop_path(
cls,
to_chop: _PathRepresentation,
path: PathRegistry,
debug: bool = False,
) -> Optional[_PathRepresentation]:
i = -1
for i, (c_token, p_token) in enumerate(
zip(to_chop, path.natural_path)
):
if isinstance(c_token, str):
if i == 0 and (
c_token.endswith(f":{_DEFAULT_TOKEN}")
or c_token.endswith(f":{_WILDCARD_TOKEN}")
):
return to_chop
elif (
c_token != f"{_RELATIONSHIP_TOKEN}:{_WILDCARD_TOKEN}"
and c_token != p_token.key # type: ignore
):
return None
if c_token is p_token:
continue
elif (
isinstance(c_token, InspectionAttr)
and insp_is_mapper(c_token)
and insp_is_mapper(p_token)
and c_token.isa(p_token)
):
continue
else:
return None
return to_chop[i + 1 :]
class Load(_AbstractLoad):
"""Represents loader options which modify the state of a
ORM-enabled :class:`_sql.Select` or a legacy :class:`_query.Query` in
order to affect how various mapped attributes are loaded.
The :class:`_orm.Load` object is in most cases used implicitly behind the
scenes when one makes use of a query option like :func:`_orm.joinedload`,
:func:`_orm.defer`, or similar. It typically is not instantiated directly
except for in some very specific cases.
.. seealso::
:ref:`orm_queryguide_relationship_per_entity_wildcard` - illustrates an
example where direct use of :class:`_orm.Load` may be useful
"""
__slots__ = (
"path",
"context",
"additional_source_entities",
)
_traverse_internals = [
("path", visitors.ExtendedInternalTraversal.dp_has_cache_key),
(
"context",
visitors.InternalTraversal.dp_has_cache_key_list,
),
("propagate_to_loaders", visitors.InternalTraversal.dp_boolean),
(
"additional_source_entities",
visitors.InternalTraversal.dp_has_cache_key_list,
),
]
_cache_key_traversal = None
path: PathRegistry
context: Tuple[_LoadElement, ...]
additional_source_entities: Tuple[_InternalEntityType[Any], ...]
def __init__(self, entity: _EntityType[Any]):
insp = cast("Union[Mapper[Any], AliasedInsp[Any]]", inspect(entity))
insp._post_inspect
self.path = insp._path_registry
self.context = ()
self.propagate_to_loaders = False
self.additional_source_entities = ()
def __str__(self) -> str:
return f"Load({self.path[0]})"
@classmethod
def _construct_for_existing_path(
cls, path: AbstractEntityRegistry
) -> Load:
load = cls.__new__(cls)
load.path = path
load.context = ()
load.propagate_to_loaders = False
load.additional_source_entities = ()
return load
def _adapt_cached_option_to_uncached_option(
self, context: QueryContext, uncached_opt: ORMOption
) -> ORMOption:
if uncached_opt is self:
return self
return self._adjust_for_extra_criteria(context)
def _prepend_path(self, path: PathRegistry) -> Load:
cloned = self._clone()
cloned.context = tuple(
element._prepend_path(path) for element in self.context
)
return cloned
def _adjust_for_extra_criteria(self, context: QueryContext) -> Load:
"""Apply the current bound parameters in a QueryContext to all
occurrences "extra_criteria" stored within this ``Load`` object,
returning a new instance of this ``Load`` object.
"""
# avoid generating cache keys for the queries if we don't
# actually have any extra_criteria options, which is the
# common case
for value in self.context:
if value._extra_criteria:
break
else:
return self
replacement_cache_key = context.query._generate_cache_key()
if replacement_cache_key is None:
return self
orig_query = context.compile_state.select_statement
orig_cache_key = orig_query._generate_cache_key()
assert orig_cache_key is not None
def process(
opt: _LoadElement,
replacement_cache_key: CacheKey,
orig_cache_key: CacheKey,
) -> _LoadElement:
cloned_opt = opt._clone()
cloned_opt._extra_criteria = tuple(
replacement_cache_key._apply_params_to_element(
orig_cache_key, crit
)
for crit in cloned_opt._extra_criteria
)
return cloned_opt
cloned = self._clone()
cloned.context = tuple(
(
process(value, replacement_cache_key, orig_cache_key)
if value._extra_criteria
else value
)
for value in self.context
)
return cloned
def _reconcile_query_entities_with_us(self, mapper_entities, raiseerr):
"""called at process time to allow adjustment of the root
entity inside of _LoadElement objects.
"""
path = self.path
ezero = None
for ent in mapper_entities:
ezero = ent.entity_zero
if ezero and orm_util._entity_corresponds_to(
# technically this can be a token also, but this is
# safe to pass to _entity_corresponds_to()
ezero,
cast("_InternalEntityType[Any]", path[0]),
):
return ezero
return None
def _process(
self,
compile_state: ORMCompileState,
mapper_entities: Sequence[_MapperEntity],
raiseerr: bool,
) -> None:
reconciled_lead_entity = self._reconcile_query_entities_with_us(
mapper_entities, raiseerr
)
# if the context has a current path, this is a lazy load
has_current_path = bool(compile_state.compile_options._current_path)
for loader in self.context:
# issue #11292
# historically, propagate_to_loaders was only considered at
# object loading time, whether or not to carry along options
# onto an object's loaded state where it would be used by lazyload.
# however, the defaultload() option needs to propagate in case
# its sub-options propagate_to_loaders, but its sub-options
# that dont propagate should not be applied for lazy loaders.
# so we check again
if has_current_path and not loader.propagate_to_loaders:
continue
loader.process_compile_state(
self,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
)
def _apply_to_parent(self, parent: Load) -> None:
"""apply this :class:`_orm.Load` object as a sub-option of another
:class:`_orm.Load` object.
This method is used by the :meth:`_orm.Load.options` method.
"""
cloned = self._generate()
assert cloned.propagate_to_loaders == self.propagate_to_loaders
if not any(
orm_util._entity_corresponds_to_use_path_impl(
elem, cloned.path.odd_element(0)
)
for elem in (parent.path.odd_element(-1),)
+ parent.additional_source_entities
):
if len(cloned.path) > 1:
attrname = cloned.path[1]
parent_entity = cloned.path[0]
else:
attrname = cloned.path[0]
parent_entity = cloned.path[0]
_raise_for_does_not_link(parent.path, attrname, parent_entity)
cloned.path = PathRegistry.coerce(parent.path[0:-1] + cloned.path[:])
if self.context:
cloned.context = tuple(
value._prepend_path_from(parent) for value in self.context
)
if cloned.context:
parent.context += cloned.context
parent.additional_source_entities += (
cloned.additional_source_entities
)
@_generative
def options(self, *opts: _AbstractLoad) -> Self:
r"""Apply a series of options as sub-options to this
:class:`_orm.Load`
object.
E.g.::
query = session.query(Author)
query = query.options(
joinedload(Author.book).options(
load_only(Book.summary, Book.excerpt),
joinedload(Book.citations).options(
joinedload(Citation.author)
)
)
)
:param \*opts: A series of loader option objects (ultimately
:class:`_orm.Load` objects) which should be applied to the path
specified by this :class:`_orm.Load` object.
.. versionadded:: 1.3.6
.. seealso::
:func:`.defaultload`
:ref:`orm_queryguide_relationship_sub_options`
"""
for opt in opts:
try:
opt._apply_to_parent(self)
except AttributeError as ae:
if not isinstance(opt, _AbstractLoad):
raise sa_exc.ArgumentError(
f"Loader option {opt} is not compatible with the "
"Load.options() method."
) from ae
else:
raise
return self
def _clone_for_bind_strategy(
self,
attrs: Optional[Tuple[_AttrType, ...]],
strategy: Optional[_StrategyKey],
wildcard_key: Optional[_WildcardKeyType],
opts: Optional[_OptsType] = None,
attr_group: Optional[_AttrGroupType] = None,
propagate_to_loaders: bool = True,
reconcile_to_other: Optional[bool] = None,
extra_criteria: Optional[Tuple[Any, ...]] = None,
) -> Self:
# for individual strategy that needs to propagate, set the whole
# Load container to also propagate, so that it shows up in
# InstanceState.load_options
if propagate_to_loaders:
self.propagate_to_loaders = True
if self.path.is_token:
raise sa_exc.ArgumentError(
"Wildcard token cannot be followed by another entity"
)
elif path_is_property(self.path):
# re-use the lookup which will raise a nicely formatted
# LoaderStrategyException
if strategy:
self.path.prop._strategy_lookup(self.path.prop, strategy[0])
else:
raise sa_exc.ArgumentError(
f"Mapped attribute '{self.path.prop}' does not "
"refer to a mapped entity"
)
if attrs is None:
load_element = _ClassStrategyLoad.create(
self.path,
None,
strategy,
wildcard_key,
opts,
propagate_to_loaders,
attr_group=attr_group,
reconcile_to_other=reconcile_to_other,
extra_criteria=extra_criteria,
)
if load_element:
self.context += (load_element,)
assert opts is not None
self.additional_source_entities += cast(
"Tuple[_InternalEntityType[Any]]", opts["entities"]
)
else:
for attr in attrs:
if isinstance(attr, str):
load_element = _TokenStrategyLoad.create(
self.path,
attr,
strategy,
wildcard_key,
opts,
propagate_to_loaders,
attr_group=attr_group,
reconcile_to_other=reconcile_to_other,
extra_criteria=extra_criteria,
)
else:
load_element = _AttributeStrategyLoad.create(
self.path,
attr,
strategy,
wildcard_key,
opts,
propagate_to_loaders,
attr_group=attr_group,
reconcile_to_other=reconcile_to_other,
extra_criteria=extra_criteria,
)
if load_element:
# for relationship options, update self.path on this Load
# object with the latest path.
if wildcard_key is _RELATIONSHIP_TOKEN:
self.path = load_element.path
self.context += (load_element,)
# this seems to be effective for selectinloader,
# giving the extra match to one more level deep.
# but does not work for immediateloader, which still
# must add additional options at load time
if load_element.local_opts.get("recursion_depth", False):
r1 = load_element._recurse()
self.context += (r1,)
return self
def __getstate__(self):
d = self._shallow_to_dict()
d["path"] = self.path.serialize()
return d
def __setstate__(self, state):
state["path"] = PathRegistry.deserialize(state["path"])
self._shallow_from_dict(state)
class _WildcardLoad(_AbstractLoad):
"""represent a standalone '*' load operation"""
__slots__ = ("strategy", "path", "local_opts")
_traverse_internals = [
("strategy", visitors.ExtendedInternalTraversal.dp_plain_obj),
("path", visitors.ExtendedInternalTraversal.dp_plain_obj),
(
"local_opts",
visitors.ExtendedInternalTraversal.dp_string_multi_dict,
),
]
cache_key_traversal: _CacheKeyTraversalType = None
strategy: Optional[Tuple[Any, ...]]
local_opts: _OptsType
path: Union[Tuple[()], Tuple[str]]
propagate_to_loaders = False
def __init__(self) -> None:
self.path = ()
self.strategy = None
self.local_opts = util.EMPTY_DICT
def _clone_for_bind_strategy(
self,
attrs,
strategy,
wildcard_key,
opts=None,
attr_group=None,
propagate_to_loaders=True,
reconcile_to_other=None,
extra_criteria=None,
):
assert attrs is not None
attr = attrs[0]
assert (
wildcard_key
and isinstance(attr, str)
and attr in (_WILDCARD_TOKEN, _DEFAULT_TOKEN)
)
attr = f"{wildcard_key}:{attr}"
self.strategy = strategy
self.path = (attr,)
if opts:
self.local_opts = util.immutabledict(opts)
assert extra_criteria is None
def options(self, *opts: _AbstractLoad) -> Self:
raise NotImplementedError("Star option does not support sub-options")
def _apply_to_parent(self, parent: Load) -> None:
"""apply this :class:`_orm._WildcardLoad` object as a sub-option of
a :class:`_orm.Load` object.
This method is used by the :meth:`_orm.Load.options` method. Note
that :class:`_orm.WildcardLoad` itself can't have sub-options, but
it may be used as the sub-option of a :class:`_orm.Load` object.
"""
assert self.path
attr = self.path[0]
if attr.endswith(_DEFAULT_TOKEN):
attr = f"{attr.split(':')[0]}:{_WILDCARD_TOKEN}"
effective_path = cast(AbstractEntityRegistry, parent.path).token(attr)
assert effective_path.is_token
loader = _TokenStrategyLoad.create(
effective_path,
None,
self.strategy,
None,
self.local_opts,
self.propagate_to_loaders,
)
parent.context += (loader,)
def _process(self, compile_state, mapper_entities, raiseerr):
is_refresh = compile_state.compile_options._for_refresh_state
if is_refresh and not self.propagate_to_loaders:
return
entities = [ent.entity_zero for ent in mapper_entities]
current_path = compile_state.current_path
start_path: _PathRepresentation = self.path
if current_path:
# TODO: no cases in test suite where we actually get
# None back here
new_path = self._chop_path(start_path, current_path)
if new_path is None:
return
# chop_path does not actually "chop" a wildcard token path,
# just returns it
assert new_path == start_path
# start_path is a single-token tuple
assert start_path and len(start_path) == 1
token = start_path[0]
assert isinstance(token, str)
entity = self._find_entity_basestring(entities, token, raiseerr)
if not entity:
return
path_element = entity
# transfer our entity-less state into a Load() object
# with a real entity path. Start with the lead entity
# we just located, then go through the rest of our path
# tokens and populate into the Load().
assert isinstance(token, str)
loader = _TokenStrategyLoad.create(
path_element._path_registry,
token,
self.strategy,
None,
self.local_opts,
self.propagate_to_loaders,
raiseerr=raiseerr,
)
if not loader:
return
assert loader.path.is_token
# don't pass a reconciled lead entity here
loader.process_compile_state(
self, compile_state, mapper_entities, None, raiseerr
)
return loader
def _find_entity_basestring(
self,
entities: Iterable[_InternalEntityType[Any]],
token: str,
raiseerr: bool,
) -> Optional[_InternalEntityType[Any]]:
if token.endswith(f":{_WILDCARD_TOKEN}"):
if len(list(entities)) != 1:
if raiseerr:
raise sa_exc.ArgumentError(
"Can't apply wildcard ('*') or load_only() "
f"loader option to multiple entities "
f"{', '.join(str(ent) for ent in entities)}. Specify "
"loader options for each entity individually, such as "
f"""{
", ".join(
f"Load({ent}).some_option('*')"
for ent in entities
)
}."""
)
elif token.endswith(_DEFAULT_TOKEN):
raiseerr = False
for ent in entities:
# return only the first _MapperEntity when searching
# based on string prop name. Ideally object
# attributes are used to specify more exactly.
return ent
else:
if raiseerr:
raise sa_exc.ArgumentError(
"Query has only expression-based entities - "
f'can\'t find property named "{token}".'
)
else:
return None
def __getstate__(self) -> Dict[str, Any]:
d = self._shallow_to_dict()
return d
def __setstate__(self, state: Dict[str, Any]) -> None:
self._shallow_from_dict(state)
class _LoadElement(
cache_key.HasCacheKey, traversals.HasShallowCopy, visitors.Traversible
):
"""represents strategy information to select for a LoaderStrategy
and pass options to it.
:class:`._LoadElement` objects provide the inner datastructure
stored by a :class:`_orm.Load` object and are also the object passed
to methods like :meth:`.LoaderStrategy.setup_query`.
.. versionadded:: 2.0
"""
__slots__ = (
"path",
"strategy",
"propagate_to_loaders",
"local_opts",
"_extra_criteria",
"_reconcile_to_other",
)
__visit_name__ = "load_element"
_traverse_internals = [
("path", visitors.ExtendedInternalTraversal.dp_has_cache_key),
("strategy", visitors.ExtendedInternalTraversal.dp_plain_obj),
(
"local_opts",
visitors.ExtendedInternalTraversal.dp_string_multi_dict,
),
("_extra_criteria", visitors.InternalTraversal.dp_clauseelement_list),
("propagate_to_loaders", visitors.InternalTraversal.dp_plain_obj),
("_reconcile_to_other", visitors.InternalTraversal.dp_plain_obj),
]
_cache_key_traversal = None
_extra_criteria: Tuple[Any, ...]
_reconcile_to_other: Optional[bool]
strategy: Optional[_StrategyKey]
path: PathRegistry
propagate_to_loaders: bool
local_opts: util.immutabledict[str, Any]
is_token_strategy: bool
is_class_strategy: bool
def __hash__(self) -> int:
return id(self)
def __eq__(self, other):
return traversals.compare(self, other)
@property
def is_opts_only(self) -> bool:
return bool(self.local_opts and self.strategy is None)
def _clone(self, **kw: Any) -> _LoadElement:
cls = self.__class__
s = cls.__new__(cls)
self._shallow_copy_to(s)
return s
def _update_opts(self, **kw: Any) -> _LoadElement:
new = self._clone()
new.local_opts = new.local_opts.union(kw)
return new
def __getstate__(self) -> Dict[str, Any]:
d = self._shallow_to_dict()
d["path"] = self.path.serialize()
return d
def __setstate__(self, state: Dict[str, Any]) -> None:
state["path"] = PathRegistry.deserialize(state["path"])
self._shallow_from_dict(state)
def _raise_for_no_match(self, parent_loader, mapper_entities):
path = parent_loader.path
found_entities = False
for ent in mapper_entities:
ezero = ent.entity_zero
if ezero:
found_entities = True
break
if not found_entities:
raise sa_exc.ArgumentError(
"Query has only expression-based entities; "
f"attribute loader options for {path[0]} can't "
"be applied here."
)
else:
raise sa_exc.ArgumentError(
f"Mapped class {path[0]} does not apply to any of the "
f"root entities in this query, e.g. "
f"""{
", ".join(
str(x.entity_zero)
for x in mapper_entities if x.entity_zero
)}. Please """
"specify the full path "
"from one of the root entities to the target "
"attribute. "
)
def _adjust_effective_path_for_current_path(
self, effective_path: PathRegistry, current_path: PathRegistry
) -> Optional[PathRegistry]:
"""receives the 'current_path' entry from an :class:`.ORMCompileState`
instance, which is set during lazy loads and secondary loader strategy
loads, and adjusts the given path to be relative to the
current_path.
E.g. given a loader path and current path::
lp: User -> orders -> Order -> items -> Item -> keywords -> Keyword
cp: User -> orders -> Order -> items
The adjusted path would be::
Item -> keywords -> Keyword
"""
chopped_start_path = Load._chop_path(
effective_path.natural_path, current_path
)
if not chopped_start_path:
return None
tokens_removed_from_start_path = len(effective_path) - len(
chopped_start_path
)
loader_lead_path_element = self.path[tokens_removed_from_start_path]
effective_path = PathRegistry.coerce(
(loader_lead_path_element,) + chopped_start_path[1:]
)
return effective_path
def _init_path(
self, path, attr, wildcard_key, attr_group, raiseerr, extra_criteria
):
"""Apply ORM attributes and/or wildcard to an existing path, producing
a new path.
This method is used within the :meth:`.create` method to initialize
a :class:`._LoadElement` object.
"""
raise NotImplementedError()
def _prepare_for_compile_state(
self,
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
):
"""implemented by subclasses."""
raise NotImplementedError()
def process_compile_state(
self,
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
):
"""populate ORMCompileState.attributes with loader state for this
_LoadElement.
"""
keys = self._prepare_for_compile_state(
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
)
for key in keys:
if key in compile_state.attributes:
compile_state.attributes[key] = _LoadElement._reconcile(
self, compile_state.attributes[key]
)
else:
compile_state.attributes[key] = self
@classmethod
def create(
cls,
path: PathRegistry,
attr: Union[_AttrType, _StrPathToken, None],
strategy: Optional[_StrategyKey],
wildcard_key: Optional[_WildcardKeyType],
local_opts: Optional[_OptsType],
propagate_to_loaders: bool,
raiseerr: bool = True,
attr_group: Optional[_AttrGroupType] = None,
reconcile_to_other: Optional[bool] = None,
extra_criteria: Optional[Tuple[Any, ...]] = None,
) -> _LoadElement:
"""Create a new :class:`._LoadElement` object."""
opt = cls.__new__(cls)
opt.path = path
opt.strategy = strategy
opt.propagate_to_loaders = propagate_to_loaders
opt.local_opts = (
util.immutabledict(local_opts) if local_opts else util.EMPTY_DICT
)
opt._extra_criteria = ()
if reconcile_to_other is not None:
opt._reconcile_to_other = reconcile_to_other
elif strategy is None and not local_opts:
opt._reconcile_to_other = True
else:
opt._reconcile_to_other = None
path = opt._init_path(
path, attr, wildcard_key, attr_group, raiseerr, extra_criteria
)
if not path:
return None # type: ignore
assert opt.is_token_strategy == path.is_token
opt.path = path
return opt
def __init__(self) -> None:
raise NotImplementedError()
def _recurse(self) -> _LoadElement:
cloned = self._clone()
cloned.path = PathRegistry.coerce(self.path[:] + self.path[-2:])
return cloned
def _prepend_path_from(self, parent: Load) -> _LoadElement:
"""adjust the path of this :class:`._LoadElement` to be
a subpath of that of the given parent :class:`_orm.Load` object's
path.
This is used by the :meth:`_orm.Load._apply_to_parent` method,
which is in turn part of the :meth:`_orm.Load.options` method.
"""
if not any(
orm_util._entity_corresponds_to_use_path_impl(
elem,
self.path.odd_element(0),
)
for elem in (parent.path.odd_element(-1),)
+ parent.additional_source_entities
):
raise sa_exc.ArgumentError(
f'Attribute "{self.path[1]}" does not link '
f'from element "{parent.path[-1]}".'
)
return self._prepend_path(parent.path)
def _prepend_path(self, path: PathRegistry) -> _LoadElement:
cloned = self._clone()
assert cloned.strategy == self.strategy
assert cloned.local_opts == self.local_opts
assert cloned.is_class_strategy == self.is_class_strategy
cloned.path = PathRegistry.coerce(path[0:-1] + cloned.path[:])
return cloned
@staticmethod
def _reconcile(
replacement: _LoadElement, existing: _LoadElement
) -> _LoadElement:
"""define behavior for when two Load objects are to be put into
the context.attributes under the same key.
:param replacement: ``_LoadElement`` that seeks to replace the
existing one
:param existing: ``_LoadElement`` that is already present.
"""
# mapper inheritance loading requires fine-grained "block other
# options" / "allow these options to be overridden" behaviors
# see test_poly_loading.py
if replacement._reconcile_to_other:
return existing
elif replacement._reconcile_to_other is False:
return replacement
elif existing._reconcile_to_other:
return replacement
elif existing._reconcile_to_other is False:
return existing
if existing is replacement:
return replacement
elif (
existing.strategy == replacement.strategy
and existing.local_opts == replacement.local_opts
):
return replacement
elif replacement.is_opts_only:
existing = existing._clone()
existing.local_opts = existing.local_opts.union(
replacement.local_opts
)
existing._extra_criteria += replacement._extra_criteria
return existing
elif existing.is_opts_only:
replacement = replacement._clone()
replacement.local_opts = replacement.local_opts.union(
existing.local_opts
)
replacement._extra_criteria += existing._extra_criteria
return replacement
elif replacement.path.is_token:
# use 'last one wins' logic for wildcard options. this is also
# kind of inconsistent vs. options that are specific paths which
# will raise as below
return replacement
raise sa_exc.InvalidRequestError(
f"Loader strategies for {replacement.path} conflict"
)
class _AttributeStrategyLoad(_LoadElement):
"""Loader strategies against specific relationship or column paths.
e.g.::
joinedload(User.addresses)
defer(Order.name)
selectinload(User.orders).lazyload(Order.items)
"""
__slots__ = ("_of_type", "_path_with_polymorphic_path")
__visit_name__ = "attribute_strategy_load_element"
_traverse_internals = _LoadElement._traverse_internals + [
("_of_type", visitors.ExtendedInternalTraversal.dp_multi),
(
"_path_with_polymorphic_path",
visitors.ExtendedInternalTraversal.dp_has_cache_key,
),
]
_of_type: Union[Mapper[Any], AliasedInsp[Any], None]
_path_with_polymorphic_path: Optional[PathRegistry]
is_class_strategy = False
is_token_strategy = False
def _init_path(
self, path, attr, wildcard_key, attr_group, raiseerr, extra_criteria
):
assert attr is not None
self._of_type = None
self._path_with_polymorphic_path = None
insp, _, prop = _parse_attr_argument(attr)
if insp.is_property:
# direct property can be sent from internal strategy logic
# that sets up specific loaders, such as
# emit_lazyload->_lazyload_reverse
# prop = found_property = attr
prop = attr
path = path[prop]
if path.has_entity:
path = path.entity_path
return path
elif not insp.is_attribute:
# should not reach here;
assert False
# here we assume we have user-passed InstrumentedAttribute
if not orm_util._entity_corresponds_to_use_path_impl(
path[-1], attr.parent
):
if raiseerr:
if attr_group and attr is not attr_group[0]:
raise sa_exc.ArgumentError(
"Can't apply wildcard ('*') or load_only() "
"loader option to multiple entities in the "
"same option. Use separate options per entity."
)
else:
_raise_for_does_not_link(path, str(attr), attr.parent)
else:
return None
# note the essential logic of this attribute was very different in
# 1.4, where there were caching failures in e.g.
# test_relationship_criteria.py::RelationshipCriteriaTest::
# test_selectinload_nested_criteria[True] if an existing
# "_extra_criteria" on a Load object were replaced with that coming
# from an attribute. This appears to have been an artifact of how
# _UnboundLoad / Load interacted together, which was opaque and
# poorly defined.
if extra_criteria:
assert not attr._extra_criteria
self._extra_criteria = extra_criteria
else:
self._extra_criteria = attr._extra_criteria
if getattr(attr, "_of_type", None):
ac = attr._of_type
ext_info = inspect(ac)
self._of_type = ext_info
self._path_with_polymorphic_path = path.entity_path[prop]
path = path[prop][ext_info]
else:
path = path[prop]
if path.has_entity:
path = path.entity_path
return path
def _generate_extra_criteria(self, context):
"""Apply the current bound parameters in a QueryContext to the
immediate "extra_criteria" stored with this Load object.
Load objects are typically pulled from the cached version of
the statement from a QueryContext. The statement currently being
executed will have new values (and keys) for bound parameters in the
extra criteria which need to be applied by loader strategies when
they handle this criteria for a result set.
"""
assert (
self._extra_criteria
), "this should only be called if _extra_criteria is present"
orig_query = context.compile_state.select_statement
current_query = context.query
# NOTE: while it seems like we should not do the "apply" operation
# here if orig_query is current_query, skipping it in the "optimized"
# case causes the query to be different from a cache key perspective,
# because we are creating a copy of the criteria which is no longer
# the same identity of the _extra_criteria in the loader option
# itself. cache key logic produces a different key for
# (A, copy_of_A) vs. (A, A), because in the latter case it shortens
# the second part of the key to just indicate on identity.
# if orig_query is current_query:
# not cached yet. just do the and_()
# return and_(*self._extra_criteria)
k1 = orig_query._generate_cache_key()
k2 = current_query._generate_cache_key()
return k2._apply_params_to_element(k1, and_(*self._extra_criteria))
def _set_of_type_info(self, context, current_path):
assert self._path_with_polymorphic_path
pwpi = self._of_type
assert pwpi
if not pwpi.is_aliased_class:
pwpi = inspect(
orm_util.AliasedInsp._with_polymorphic_factory(
pwpi.mapper.base_mapper,
(pwpi.mapper,),
aliased=True,
_use_mapper_path=True,
)
)
start_path = self._path_with_polymorphic_path
if current_path:
new_path = self._adjust_effective_path_for_current_path(
start_path, current_path
)
if new_path is None:
return
start_path = new_path
key = ("path_with_polymorphic", start_path.natural_path)
if key in context:
existing_aliased_insp = context[key]
this_aliased_insp = pwpi
new_aliased_insp = existing_aliased_insp._merge_with(
this_aliased_insp
)
context[key] = new_aliased_insp
else:
context[key] = pwpi
def _prepare_for_compile_state(
self,
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
):
# _AttributeStrategyLoad
current_path = compile_state.current_path
is_refresh = compile_state.compile_options._for_refresh_state
assert not self.path.is_token
if is_refresh and not self.propagate_to_loaders:
return []
if self._of_type:
# apply additional with_polymorphic alias that may have been
# generated. this has to happen even if this is a defaultload
self._set_of_type_info(compile_state.attributes, current_path)
# omit setting loader attributes for a "defaultload" type of option
if not self.strategy and not self.local_opts:
return []
if raiseerr and not reconciled_lead_entity:
self._raise_for_no_match(parent_loader, mapper_entities)
if self.path.has_entity:
effective_path = self.path.parent
else:
effective_path = self.path
if current_path:
assert effective_path is not None
effective_path = self._adjust_effective_path_for_current_path(
effective_path, current_path
)
if effective_path is None:
return []
return [("loader", cast(PathRegistry, effective_path).natural_path)]
def __getstate__(self):
d = super().__getstate__()
# can't pickle this. See
# test_pickled.py -> test_lazyload_extra_criteria_not_supported
# where we should be emitting a warning for the usual case where this
# would be non-None
d["_extra_criteria"] = ()
if self._path_with_polymorphic_path:
d["_path_with_polymorphic_path"] = (
self._path_with_polymorphic_path.serialize()
)
if self._of_type:
if self._of_type.is_aliased_class:
d["_of_type"] = None
elif self._of_type.is_mapper:
d["_of_type"] = self._of_type.class_
else:
assert False, "unexpected object for _of_type"
return d
def __setstate__(self, state):
super().__setstate__(state)
if state.get("_path_with_polymorphic_path", None):
self._path_with_polymorphic_path = PathRegistry.deserialize(
state["_path_with_polymorphic_path"]
)
else:
self._path_with_polymorphic_path = None
if state.get("_of_type", None):
self._of_type = inspect(state["_of_type"])
else:
self._of_type = None
class _TokenStrategyLoad(_LoadElement):
"""Loader strategies against wildcard attributes
e.g.::
raiseload('*')
Load(User).lazyload('*')
defer('*')
load_only(User.name, User.email) # will create a defer('*')
joinedload(User.addresses).raiseload('*')
"""
__visit_name__ = "token_strategy_load_element"
inherit_cache = True
is_class_strategy = False
is_token_strategy = True
def _init_path(
self, path, attr, wildcard_key, attr_group, raiseerr, extra_criteria
):
# assert isinstance(attr, str) or attr is None
if attr is not None:
default_token = attr.endswith(_DEFAULT_TOKEN)
if attr.endswith(_WILDCARD_TOKEN) or default_token:
if wildcard_key:
attr = f"{wildcard_key}:{attr}"
path = path.token(attr)
return path
else:
raise sa_exc.ArgumentError(
"Strings are not accepted for attribute names in loader "
"options; please use class-bound attributes directly."
)
return path
def _prepare_for_compile_state(
self,
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
):
# _TokenStrategyLoad
current_path = compile_state.current_path
is_refresh = compile_state.compile_options._for_refresh_state
assert self.path.is_token
if is_refresh and not self.propagate_to_loaders:
return []
# omit setting attributes for a "defaultload" type of option
if not self.strategy and not self.local_opts:
return []
effective_path = self.path
if reconciled_lead_entity:
effective_path = PathRegistry.coerce(
(reconciled_lead_entity,) + effective_path.path[1:]
)
if current_path:
new_effective_path = self._adjust_effective_path_for_current_path(
effective_path, current_path
)
if new_effective_path is None:
return []
effective_path = new_effective_path
# for a wildcard token, expand out the path we set
# to encompass everything from the query entity on
# forward. not clear if this is necessary when current_path
# is set.
return [
("loader", natural_path)
for natural_path in (
cast(
TokenRegistry, effective_path
)._generate_natural_for_superclasses()
)
]
class _ClassStrategyLoad(_LoadElement):
"""Loader strategies that deals with a class as a target, not
an attribute path
e.g.::
q = s.query(Person).options(
selectin_polymorphic(Person, [Engineer, Manager])
)
"""
inherit_cache = True
is_class_strategy = True
is_token_strategy = False
__visit_name__ = "class_strategy_load_element"
def _init_path(
self, path, attr, wildcard_key, attr_group, raiseerr, extra_criteria
):
return path
def _prepare_for_compile_state(
self,
parent_loader,
compile_state,
mapper_entities,
reconciled_lead_entity,
raiseerr,
):
# _ClassStrategyLoad
current_path = compile_state.current_path
is_refresh = compile_state.compile_options._for_refresh_state
if is_refresh and not self.propagate_to_loaders:
return []
# omit setting attributes for a "defaultload" type of option
if not self.strategy and not self.local_opts:
return []
effective_path = self.path
if current_path:
new_effective_path = self._adjust_effective_path_for_current_path(
effective_path, current_path
)
if new_effective_path is None:
return []
effective_path = new_effective_path
return [("loader", effective_path.natural_path)]
def _generate_from_keys(
meth: Callable[..., _AbstractLoad],
keys: Tuple[_AttrType, ...],
chained: bool,
kw: Any,
) -> _AbstractLoad:
lead_element: Optional[_AbstractLoad] = None
attr: Any
for is_default, _keys in (True, keys[0:-1]), (False, keys[-1:]):
for attr in _keys:
if isinstance(attr, str):
if attr.startswith("." + _WILDCARD_TOKEN):
util.warn_deprecated(
"The undocumented `.{WILDCARD}` format is "
"deprecated "
"and will be removed in a future version as "
"it is "
"believed to be unused. "
"If you have been using this functionality, "
"please "
"comment on Issue #4390 on the SQLAlchemy project "
"tracker.",
version="1.4",
)
attr = attr[1:]
if attr == _WILDCARD_TOKEN:
if is_default:
raise sa_exc.ArgumentError(
"Wildcard token cannot be followed by "
"another entity",
)
if lead_element is None:
lead_element = _WildcardLoad()
lead_element = meth(lead_element, _DEFAULT_TOKEN, **kw)
else:
raise sa_exc.ArgumentError(
"Strings are not accepted for attribute names in "
"loader options; please use class-bound "
"attributes directly.",
)
else:
if lead_element is None:
_, lead_entity, _ = _parse_attr_argument(attr)
lead_element = Load(lead_entity)
if is_default:
if not chained:
lead_element = lead_element.defaultload(attr)
else:
lead_element = meth(
lead_element, attr, _is_chain=True, **kw
)
else:
lead_element = meth(lead_element, attr, **kw)
assert lead_element
return lead_element
def _parse_attr_argument(
attr: _AttrType,
) -> Tuple[InspectionAttr, _InternalEntityType[Any], MapperProperty[Any]]:
"""parse an attribute or wildcard argument to produce an
:class:`._AbstractLoad` instance.
This is used by the standalone loader strategy functions like
``joinedload()``, ``defer()``, etc. to produce :class:`_orm.Load` or
:class:`._WildcardLoad` objects.
"""
try:
# TODO: need to figure out this None thing being returned by
# inspect(), it should not have None as an option in most cases
# if at all
insp: InspectionAttr = inspect(attr) # type: ignore
except sa_exc.NoInspectionAvailable as err:
raise sa_exc.ArgumentError(
"expected ORM mapped attribute for loader strategy argument"
) from err
lead_entity: _InternalEntityType[Any]
if insp_is_mapper_property(insp):
lead_entity = insp.parent
prop = insp
elif insp_is_attribute(insp):
lead_entity = insp.parent
prop = insp.prop
else:
raise sa_exc.ArgumentError(
"expected ORM mapped attribute for loader strategy argument"
)
return insp, lead_entity, prop
def loader_unbound_fn(fn: _FN) -> _FN:
"""decorator that applies docstrings between standalone loader functions
and the loader methods on :class:`._AbstractLoad`.
"""
bound_fn = getattr(_AbstractLoad, fn.__name__)
fn_doc = bound_fn.__doc__
bound_fn.__doc__ = f"""Produce a new :class:`_orm.Load` object with the
:func:`_orm.{fn.__name__}` option applied.
See :func:`_orm.{fn.__name__}` for usage examples.
"""
fn.__doc__ = fn_doc
return fn
# standalone functions follow. docstrings are filled in
# by the ``@loader_unbound_fn`` decorator.
@loader_unbound_fn
def contains_eager(*keys: _AttrType, **kw: Any) -> _AbstractLoad:
return _generate_from_keys(Load.contains_eager, keys, True, kw)
@loader_unbound_fn
def load_only(*attrs: _AttrType, raiseload: bool = False) -> _AbstractLoad:
# TODO: attrs against different classes. we likely have to
# add some extra state to Load of some kind
_, lead_element, _ = _parse_attr_argument(attrs[0])
return Load(lead_element).load_only(*attrs, raiseload=raiseload)
@loader_unbound_fn
def joinedload(*keys: _AttrType, **kw: Any) -> _AbstractLoad:
return _generate_from_keys(Load.joinedload, keys, False, kw)
@loader_unbound_fn
def subqueryload(*keys: _AttrType) -> _AbstractLoad:
return _generate_from_keys(Load.subqueryload, keys, False, {})
@loader_unbound_fn
def selectinload(
*keys: _AttrType, recursion_depth: Optional[int] = None
) -> _AbstractLoad:
return _generate_from_keys(
Load.selectinload, keys, False, {"recursion_depth": recursion_depth}
)
@loader_unbound_fn
def lazyload(*keys: _AttrType) -> _AbstractLoad:
return _generate_from_keys(Load.lazyload, keys, False, {})
@loader_unbound_fn
def immediateload(
*keys: _AttrType, recursion_depth: Optional[int] = None
) -> _AbstractLoad:
return _generate_from_keys(
Load.immediateload, keys, False, {"recursion_depth": recursion_depth}
)
@loader_unbound_fn
def noload(*keys: _AttrType) -> _AbstractLoad:
return _generate_from_keys(Load.noload, keys, False, {})
@loader_unbound_fn
def raiseload(*keys: _AttrType, **kw: Any) -> _AbstractLoad:
return _generate_from_keys(Load.raiseload, keys, False, kw)
@loader_unbound_fn
def defaultload(*keys: _AttrType) -> _AbstractLoad:
return _generate_from_keys(Load.defaultload, keys, False, {})
@loader_unbound_fn
def defer(
key: _AttrType, *addl_attrs: _AttrType, raiseload: bool = False
) -> _AbstractLoad:
if addl_attrs:
util.warn_deprecated(
"The *addl_attrs on orm.defer is deprecated. Please use "
"method chaining in conjunction with defaultload() to "
"indicate a path.",
version="1.3",
)
if raiseload:
kw = {"raiseload": raiseload}
else:
kw = {}
return _generate_from_keys(Load.defer, (key,) + addl_attrs, False, kw)
@loader_unbound_fn
def undefer(key: _AttrType, *addl_attrs: _AttrType) -> _AbstractLoad:
if addl_attrs:
util.warn_deprecated(
"The *addl_attrs on orm.undefer is deprecated. Please use "
"method chaining in conjunction with defaultload() to "
"indicate a path.",
version="1.3",
)
return _generate_from_keys(Load.undefer, (key,) + addl_attrs, False, {})
@loader_unbound_fn
def undefer_group(name: str) -> _AbstractLoad:
element = _WildcardLoad()
return element.undefer_group(name)
@loader_unbound_fn
def with_expression(
key: _AttrType, expression: _ColumnExpressionArgument[Any]
) -> _AbstractLoad:
return _generate_from_keys(
Load.with_expression, (key,), False, {"expression": expression}
)
@loader_unbound_fn
def selectin_polymorphic(
base_cls: _EntityType[Any], classes: Iterable[Type[Any]]
) -> _AbstractLoad:
ul = Load(base_cls)
return ul.selectin_polymorphic(classes)
def _raise_for_does_not_link(path, attrname, parent_entity):
if len(path) > 1:
path_is_of_type = path[-1].entity is not path[-2].mapper.class_
if insp_is_aliased_class(parent_entity):
parent_entity_str = str(parent_entity)
else:
parent_entity_str = parent_entity.class_.__name__
raise sa_exc.ArgumentError(
f'ORM mapped entity or attribute "{attrname}" does not '
f'link from relationship "{path[-2]}%s".%s'
% (
f".of_type({path[-1]})" if path_is_of_type else "",
(
" Did you mean to use "
f'"{path[-2]}'
f'.of_type({parent_entity_str})" or "loadopt.options('
f"selectin_polymorphic({path[-2].mapper.class_.__name__}, "
f'[{parent_entity_str}]), ...)" ?'
if not path_is_of_type
and not path[-1].is_aliased_class
and orm_util._entity_corresponds_to(
path.entity, inspect(parent_entity).mapper
)
else ""
),
)
)
else:
raise sa_exc.ArgumentError(
f'ORM mapped attribute "{attrname}" does not '
f'link mapped class "{path[-1]}"'
)
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