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Diffstat (limited to 'venv/lib/python3.11/site-packages/sqlalchemy/orm/strategies.py')
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diff --git a/venv/lib/python3.11/site-packages/sqlalchemy/orm/strategies.py b/venv/lib/python3.11/site-packages/sqlalchemy/orm/strategies.py new file mode 100644 index 0000000..20c3b9c --- /dev/null +++ b/venv/lib/python3.11/site-packages/sqlalchemy/orm/strategies.py @@ -0,0 +1,3344 @@ +# orm/strategies.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: ignore-errors + + +"""sqlalchemy.orm.interfaces.LoaderStrategy + implementations, and related MapperOptions.""" + +from __future__ import annotations + +import collections +import itertools +from typing import Any +from typing import Dict +from typing import Tuple +from typing import TYPE_CHECKING + +from . import attributes +from . import exc as orm_exc +from . import interfaces +from . import loading +from . import path_registry +from . import properties +from . import query +from . import relationships +from . import unitofwork +from . import util as orm_util +from .base import _DEFER_FOR_STATE +from .base import _RAISE_FOR_STATE +from .base import _SET_DEFERRED_EXPIRED +from .base import ATTR_WAS_SET +from .base import LoaderCallableStatus +from .base import PASSIVE_OFF +from .base import PassiveFlag +from .context import _column_descriptions +from .context import ORMCompileState +from .context import ORMSelectCompileState +from .context import QueryContext +from .interfaces import LoaderStrategy +from .interfaces import StrategizedProperty +from .session import _state_session +from .state import InstanceState +from .strategy_options import Load +from .util import _none_set +from .util import AliasedClass +from .. import event +from .. import exc as sa_exc +from .. import inspect +from .. import log +from .. import sql +from .. import util +from ..sql import util as sql_util +from ..sql import visitors +from ..sql.selectable import LABEL_STYLE_TABLENAME_PLUS_COL +from ..sql.selectable import Select + +if TYPE_CHECKING: + from .relationships import RelationshipProperty + from ..sql.elements import ColumnElement + + +def _register_attribute( + prop, + mapper, + useobject, + compare_function=None, + typecallable=None, + callable_=None, + proxy_property=None, + active_history=False, + impl_class=None, + **kw, +): + listen_hooks = [] + + uselist = useobject and prop.uselist + + if useobject and prop.single_parent: + listen_hooks.append(single_parent_validator) + + if prop.key in prop.parent.validators: + fn, opts = prop.parent.validators[prop.key] + listen_hooks.append( + lambda desc, prop: orm_util._validator_events( + desc, prop.key, fn, **opts + ) + ) + + if useobject: + listen_hooks.append(unitofwork.track_cascade_events) + + # need to assemble backref listeners + # after the singleparentvalidator, mapper validator + if useobject: + backref = prop.back_populates + if backref and prop._effective_sync_backref: + listen_hooks.append( + lambda desc, prop: attributes.backref_listeners( + desc, backref, uselist + ) + ) + + # a single MapperProperty is shared down a class inheritance + # hierarchy, so we set up attribute instrumentation and backref event + # for each mapper down the hierarchy. + + # typically, "mapper" is the same as prop.parent, due to the way + # the configure_mappers() process runs, however this is not strongly + # enforced, and in the case of a second configure_mappers() run the + # mapper here might not be prop.parent; also, a subclass mapper may + # be called here before a superclass mapper. That is, can't depend + # on mappers not already being set up so we have to check each one. + + for m in mapper.self_and_descendants: + if prop is m._props.get( + prop.key + ) and not m.class_manager._attr_has_impl(prop.key): + desc = attributes.register_attribute_impl( + m.class_, + prop.key, + parent_token=prop, + uselist=uselist, + compare_function=compare_function, + useobject=useobject, + trackparent=useobject + and ( + prop.single_parent + or prop.direction is interfaces.ONETOMANY + ), + typecallable=typecallable, + callable_=callable_, + active_history=active_history, + impl_class=impl_class, + send_modified_events=not useobject or not prop.viewonly, + doc=prop.doc, + **kw, + ) + + for hook in listen_hooks: + hook(desc, prop) + + +@properties.ColumnProperty.strategy_for(instrument=False, deferred=False) +class UninstrumentedColumnLoader(LoaderStrategy): + """Represent a non-instrumented MapperProperty. + + The polymorphic_on argument of mapper() often results in this, + if the argument is against the with_polymorphic selectable. + + """ + + __slots__ = ("columns",) + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.columns = self.parent_property.columns + + def setup_query( + self, + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection=None, + **kwargs, + ): + for c in self.columns: + if adapter: + c = adapter.columns[c] + compile_state._append_dedupe_col_collection(c, column_collection) + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + pass + + +@log.class_logger +@properties.ColumnProperty.strategy_for(instrument=True, deferred=False) +class ColumnLoader(LoaderStrategy): + """Provide loading behavior for a :class:`.ColumnProperty`.""" + + __slots__ = "columns", "is_composite" + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.columns = self.parent_property.columns + self.is_composite = hasattr(self.parent_property, "composite_class") + + def setup_query( + self, + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection, + memoized_populators, + check_for_adapt=False, + **kwargs, + ): + for c in self.columns: + if adapter: + if check_for_adapt: + c = adapter.adapt_check_present(c) + if c is None: + return + else: + c = adapter.columns[c] + + compile_state._append_dedupe_col_collection(c, column_collection) + + fetch = self.columns[0] + if adapter: + fetch = adapter.columns[fetch] + if fetch is None: + # None happens here only for dml bulk_persistence cases + # when context.DMLReturningColFilter is used + return + + memoized_populators[self.parent_property] = fetch + + def init_class_attribute(self, mapper): + self.is_class_level = True + coltype = self.columns[0].type + # TODO: check all columns ? check for foreign key as well? + active_history = ( + self.parent_property.active_history + or self.columns[0].primary_key + or ( + mapper.version_id_col is not None + and mapper._columntoproperty.get(mapper.version_id_col, None) + is self.parent_property + ) + ) + + _register_attribute( + self.parent_property, + mapper, + useobject=False, + compare_function=coltype.compare_values, + active_history=active_history, + ) + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + # look through list of columns represented here + # to see which, if any, is present in the row. + + for col in self.columns: + if adapter: + col = adapter.columns[col] + getter = result._getter(col, False) + if getter: + populators["quick"].append((self.key, getter)) + break + else: + populators["expire"].append((self.key, True)) + + +@log.class_logger +@properties.ColumnProperty.strategy_for(query_expression=True) +class ExpressionColumnLoader(ColumnLoader): + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + + # compare to the "default" expression that is mapped in + # the column. If it's sql.null, we don't need to render + # unless an expr is passed in the options. + null = sql.null().label(None) + self._have_default_expression = any( + not c.compare(null) for c in self.parent_property.columns + ) + + def setup_query( + self, + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection, + memoized_populators, + **kwargs, + ): + columns = None + if loadopt and loadopt._extra_criteria: + columns = loadopt._extra_criteria + + elif self._have_default_expression: + columns = self.parent_property.columns + + if columns is None: + return + + for c in columns: + if adapter: + c = adapter.columns[c] + compile_state._append_dedupe_col_collection(c, column_collection) + + fetch = columns[0] + if adapter: + fetch = adapter.columns[fetch] + if fetch is None: + # None is not expected to be the result of any + # adapter implementation here, however there may be theoretical + # usages of returning() with context.DMLReturningColFilter + return + + memoized_populators[self.parent_property] = fetch + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + # look through list of columns represented here + # to see which, if any, is present in the row. + if loadopt and loadopt._extra_criteria: + columns = loadopt._extra_criteria + + for col in columns: + if adapter: + col = adapter.columns[col] + getter = result._getter(col, False) + if getter: + populators["quick"].append((self.key, getter)) + break + else: + populators["expire"].append((self.key, True)) + + def init_class_attribute(self, mapper): + self.is_class_level = True + + _register_attribute( + self.parent_property, + mapper, + useobject=False, + compare_function=self.columns[0].type.compare_values, + accepts_scalar_loader=False, + ) + + +@log.class_logger +@properties.ColumnProperty.strategy_for(deferred=True, instrument=True) +@properties.ColumnProperty.strategy_for( + deferred=True, instrument=True, raiseload=True +) +@properties.ColumnProperty.strategy_for(do_nothing=True) +class DeferredColumnLoader(LoaderStrategy): + """Provide loading behavior for a deferred :class:`.ColumnProperty`.""" + + __slots__ = "columns", "group", "raiseload" + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + if hasattr(self.parent_property, "composite_class"): + raise NotImplementedError( + "Deferred loading for composite types not implemented yet" + ) + self.raiseload = self.strategy_opts.get("raiseload", False) + self.columns = self.parent_property.columns + self.group = self.parent_property.group + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + # for a DeferredColumnLoader, this method is only used during a + # "row processor only" query; see test_deferred.py -> + # tests with "rowproc_only" in their name. As of the 1.0 series, + # loading._instance_processor doesn't use a "row processing" function + # to populate columns, instead it uses data in the "populators" + # dictionary. Normally, the DeferredColumnLoader.setup_query() + # sets up that data in the "memoized_populators" dictionary + # and "create_row_processor()" here is never invoked. + + if ( + context.refresh_state + and context.query._compile_options._only_load_props + and self.key in context.query._compile_options._only_load_props + ): + self.parent_property._get_strategy( + (("deferred", False), ("instrument", True)) + ).create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + elif not self.is_class_level: + if self.raiseload: + set_deferred_for_local_state = ( + self.parent_property._raise_column_loader + ) + else: + set_deferred_for_local_state = ( + self.parent_property._deferred_column_loader + ) + populators["new"].append((self.key, set_deferred_for_local_state)) + else: + populators["expire"].append((self.key, False)) + + def init_class_attribute(self, mapper): + self.is_class_level = True + + _register_attribute( + self.parent_property, + mapper, + useobject=False, + compare_function=self.columns[0].type.compare_values, + callable_=self._load_for_state, + load_on_unexpire=False, + ) + + def setup_query( + self, + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection, + memoized_populators, + only_load_props=None, + **kw, + ): + if ( + ( + compile_state.compile_options._render_for_subquery + and self.parent_property._renders_in_subqueries + ) + or ( + loadopt + and set(self.columns).intersection( + self.parent._should_undefer_in_wildcard + ) + ) + or ( + loadopt + and self.group + and loadopt.local_opts.get( + "undefer_group_%s" % self.group, False + ) + ) + or (only_load_props and self.key in only_load_props) + ): + self.parent_property._get_strategy( + (("deferred", False), ("instrument", True)) + ).setup_query( + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection, + memoized_populators, + **kw, + ) + elif self.is_class_level: + memoized_populators[self.parent_property] = _SET_DEFERRED_EXPIRED + elif not self.raiseload: + memoized_populators[self.parent_property] = _DEFER_FOR_STATE + else: + memoized_populators[self.parent_property] = _RAISE_FOR_STATE + + def _load_for_state(self, state, passive): + if not state.key: + return LoaderCallableStatus.ATTR_EMPTY + + if not passive & PassiveFlag.SQL_OK: + return LoaderCallableStatus.PASSIVE_NO_RESULT + + localparent = state.manager.mapper + + if self.group: + toload = [ + p.key + for p in localparent.iterate_properties + if isinstance(p, StrategizedProperty) + and isinstance(p.strategy, DeferredColumnLoader) + and p.group == self.group + ] + else: + toload = [self.key] + + # narrow the keys down to just those which have no history + group = [k for k in toload if k in state.unmodified] + + session = _state_session(state) + if session is None: + raise orm_exc.DetachedInstanceError( + "Parent instance %s is not bound to a Session; " + "deferred load operation of attribute '%s' cannot proceed" + % (orm_util.state_str(state), self.key) + ) + + if self.raiseload: + self._invoke_raise_load(state, passive, "raise") + + loading.load_scalar_attributes( + state.mapper, state, set(group), PASSIVE_OFF + ) + + return LoaderCallableStatus.ATTR_WAS_SET + + def _invoke_raise_load(self, state, passive, lazy): + raise sa_exc.InvalidRequestError( + "'%s' is not available due to raiseload=True" % (self,) + ) + + +class LoadDeferredColumns: + """serializable loader object used by DeferredColumnLoader""" + + def __init__(self, key: str, raiseload: bool = False): + self.key = key + self.raiseload = raiseload + + def __call__(self, state, passive=attributes.PASSIVE_OFF): + key = self.key + + localparent = state.manager.mapper + prop = localparent._props[key] + if self.raiseload: + strategy_key = ( + ("deferred", True), + ("instrument", True), + ("raiseload", True), + ) + else: + strategy_key = (("deferred", True), ("instrument", True)) + strategy = prop._get_strategy(strategy_key) + return strategy._load_for_state(state, passive) + + +class AbstractRelationshipLoader(LoaderStrategy): + """LoaderStratgies which deal with related objects.""" + + __slots__ = "mapper", "target", "uselist", "entity" + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.mapper = self.parent_property.mapper + self.entity = self.parent_property.entity + self.target = self.parent_property.target + self.uselist = self.parent_property.uselist + + def _immediateload_create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + return self.parent_property._get_strategy( + (("lazy", "immediate"),) + ).create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(do_nothing=True) +class DoNothingLoader(LoaderStrategy): + """Relationship loader that makes no change to the object's state. + + Compared to NoLoader, this loader does not initialize the + collection/attribute to empty/none; the usual default LazyLoader will + take effect. + + """ + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(lazy="noload") +@relationships.RelationshipProperty.strategy_for(lazy=None) +class NoLoader(AbstractRelationshipLoader): + """Provide loading behavior for a :class:`.Relationship` + with "lazy=None". + + """ + + __slots__ = () + + def init_class_attribute(self, mapper): + self.is_class_level = True + + _register_attribute( + self.parent_property, + mapper, + useobject=True, + typecallable=self.parent_property.collection_class, + ) + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + def invoke_no_load(state, dict_, row): + if self.uselist: + attributes.init_state_collection(state, dict_, self.key) + else: + dict_[self.key] = None + + populators["new"].append((self.key, invoke_no_load)) + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(lazy=True) +@relationships.RelationshipProperty.strategy_for(lazy="select") +@relationships.RelationshipProperty.strategy_for(lazy="raise") +@relationships.RelationshipProperty.strategy_for(lazy="raise_on_sql") +@relationships.RelationshipProperty.strategy_for(lazy="baked_select") +class LazyLoader( + AbstractRelationshipLoader, util.MemoizedSlots, log.Identified +): + """Provide loading behavior for a :class:`.Relationship` + with "lazy=True", that is loads when first accessed. + + """ + + __slots__ = ( + "_lazywhere", + "_rev_lazywhere", + "_lazyload_reverse_option", + "_order_by", + "use_get", + "is_aliased_class", + "_bind_to_col", + "_equated_columns", + "_rev_bind_to_col", + "_rev_equated_columns", + "_simple_lazy_clause", + "_raise_always", + "_raise_on_sql", + ) + + _lazywhere: ColumnElement[bool] + _bind_to_col: Dict[str, ColumnElement[Any]] + _rev_lazywhere: ColumnElement[bool] + _rev_bind_to_col: Dict[str, ColumnElement[Any]] + + parent_property: RelationshipProperty[Any] + + def __init__( + self, parent: RelationshipProperty[Any], strategy_key: Tuple[Any, ...] + ): + super().__init__(parent, strategy_key) + self._raise_always = self.strategy_opts["lazy"] == "raise" + self._raise_on_sql = self.strategy_opts["lazy"] == "raise_on_sql" + + self.is_aliased_class = inspect(self.entity).is_aliased_class + + join_condition = self.parent_property._join_condition + ( + self._lazywhere, + self._bind_to_col, + self._equated_columns, + ) = join_condition.create_lazy_clause() + + ( + self._rev_lazywhere, + self._rev_bind_to_col, + self._rev_equated_columns, + ) = join_condition.create_lazy_clause(reverse_direction=True) + + if self.parent_property.order_by: + self._order_by = [ + sql_util._deep_annotate(elem, {"_orm_adapt": True}) + for elem in util.to_list(self.parent_property.order_by) + ] + else: + self._order_by = None + + self.logger.info("%s lazy loading clause %s", self, self._lazywhere) + + # determine if our "lazywhere" clause is the same as the mapper's + # get() clause. then we can just use mapper.get() + # + # TODO: the "not self.uselist" can be taken out entirely; a m2o + # load that populates for a list (very unusual, but is possible with + # the API) can still set for "None" and the attribute system will + # populate as an empty list. + self.use_get = ( + not self.is_aliased_class + and not self.uselist + and self.entity._get_clause[0].compare( + self._lazywhere, + use_proxies=True, + compare_keys=False, + equivalents=self.mapper._equivalent_columns, + ) + ) + + if self.use_get: + for col in list(self._equated_columns): + if col in self.mapper._equivalent_columns: + for c in self.mapper._equivalent_columns[col]: + self._equated_columns[c] = self._equated_columns[col] + + self.logger.info( + "%s will use Session.get() to optimize instance loads", self + ) + + def init_class_attribute(self, mapper): + self.is_class_level = True + + _legacy_inactive_history_style = ( + self.parent_property._legacy_inactive_history_style + ) + + if self.parent_property.active_history: + active_history = True + _deferred_history = False + + elif ( + self.parent_property.direction is not interfaces.MANYTOONE + or not self.use_get + ): + if _legacy_inactive_history_style: + active_history = True + _deferred_history = False + else: + active_history = False + _deferred_history = True + else: + active_history = _deferred_history = False + + _register_attribute( + self.parent_property, + mapper, + useobject=True, + callable_=self._load_for_state, + typecallable=self.parent_property.collection_class, + active_history=active_history, + _deferred_history=_deferred_history, + ) + + def _memoized_attr__simple_lazy_clause(self): + lazywhere = sql_util._deep_annotate( + self._lazywhere, {"_orm_adapt": True} + ) + + criterion, bind_to_col = (lazywhere, self._bind_to_col) + + params = [] + + def visit_bindparam(bindparam): + bindparam.unique = False + + visitors.traverse(criterion, {}, {"bindparam": visit_bindparam}) + + def visit_bindparam(bindparam): + if bindparam._identifying_key in bind_to_col: + params.append( + ( + bindparam.key, + bind_to_col[bindparam._identifying_key], + None, + ) + ) + elif bindparam.callable is None: + params.append((bindparam.key, None, bindparam.value)) + + criterion = visitors.cloned_traverse( + criterion, {}, {"bindparam": visit_bindparam} + ) + + return criterion, params + + def _generate_lazy_clause(self, state, passive): + criterion, param_keys = self._simple_lazy_clause + + if state is None: + return sql_util.adapt_criterion_to_null( + criterion, [key for key, ident, value in param_keys] + ) + + mapper = self.parent_property.parent + + o = state.obj() # strong ref + dict_ = attributes.instance_dict(o) + + if passive & PassiveFlag.INIT_OK: + passive ^= PassiveFlag.INIT_OK + + params = {} + for key, ident, value in param_keys: + if ident is not None: + if passive and passive & PassiveFlag.LOAD_AGAINST_COMMITTED: + value = mapper._get_committed_state_attr_by_column( + state, dict_, ident, passive + ) + else: + value = mapper._get_state_attr_by_column( + state, dict_, ident, passive + ) + + params[key] = value + + return criterion, params + + def _invoke_raise_load(self, state, passive, lazy): + raise sa_exc.InvalidRequestError( + "'%s' is not available due to lazy='%s'" % (self, lazy) + ) + + def _load_for_state( + self, + state, + passive, + loadopt=None, + extra_criteria=(), + extra_options=(), + alternate_effective_path=None, + execution_options=util.EMPTY_DICT, + ): + if not state.key and ( + ( + not self.parent_property.load_on_pending + and not state._load_pending + ) + or not state.session_id + ): + return LoaderCallableStatus.ATTR_EMPTY + + pending = not state.key + primary_key_identity = None + + use_get = self.use_get and (not loadopt or not loadopt._extra_criteria) + + if (not passive & PassiveFlag.SQL_OK and not use_get) or ( + not passive & attributes.NON_PERSISTENT_OK and pending + ): + return LoaderCallableStatus.PASSIVE_NO_RESULT + + if ( + # we were given lazy="raise" + self._raise_always + # the no_raise history-related flag was not passed + and not passive & PassiveFlag.NO_RAISE + and ( + # if we are use_get and related_object_ok is disabled, + # which means we are at most looking in the identity map + # for history purposes or otherwise returning + # PASSIVE_NO_RESULT, don't raise. This is also a + # history-related flag + not use_get + or passive & PassiveFlag.RELATED_OBJECT_OK + ) + ): + self._invoke_raise_load(state, passive, "raise") + + session = _state_session(state) + if not session: + if passive & PassiveFlag.NO_RAISE: + return LoaderCallableStatus.PASSIVE_NO_RESULT + + raise orm_exc.DetachedInstanceError( + "Parent instance %s is not bound to a Session; " + "lazy load operation of attribute '%s' cannot proceed" + % (orm_util.state_str(state), self.key) + ) + + # if we have a simple primary key load, check the + # identity map without generating a Query at all + if use_get: + primary_key_identity = self._get_ident_for_use_get( + session, state, passive + ) + if LoaderCallableStatus.PASSIVE_NO_RESULT in primary_key_identity: + return LoaderCallableStatus.PASSIVE_NO_RESULT + elif LoaderCallableStatus.NEVER_SET in primary_key_identity: + return LoaderCallableStatus.NEVER_SET + + if _none_set.issuperset(primary_key_identity): + return None + + if ( + self.key in state.dict + and not passive & PassiveFlag.DEFERRED_HISTORY_LOAD + ): + return LoaderCallableStatus.ATTR_WAS_SET + + # look for this identity in the identity map. Delegate to the + # Query class in use, as it may have special rules for how it + # does this, including how it decides what the correct + # identity_token would be for this identity. + + instance = session._identity_lookup( + self.entity, + primary_key_identity, + passive=passive, + lazy_loaded_from=state, + ) + + if instance is not None: + if instance is LoaderCallableStatus.PASSIVE_CLASS_MISMATCH: + return None + else: + return instance + elif ( + not passive & PassiveFlag.SQL_OK + or not passive & PassiveFlag.RELATED_OBJECT_OK + ): + return LoaderCallableStatus.PASSIVE_NO_RESULT + + return self._emit_lazyload( + session, + state, + primary_key_identity, + passive, + loadopt, + extra_criteria, + extra_options, + alternate_effective_path, + execution_options, + ) + + def _get_ident_for_use_get(self, session, state, passive): + instance_mapper = state.manager.mapper + + if passive & PassiveFlag.LOAD_AGAINST_COMMITTED: + get_attr = instance_mapper._get_committed_state_attr_by_column + else: + get_attr = instance_mapper._get_state_attr_by_column + + dict_ = state.dict + + return [ + get_attr(state, dict_, self._equated_columns[pk], passive=passive) + for pk in self.mapper.primary_key + ] + + @util.preload_module("sqlalchemy.orm.strategy_options") + def _emit_lazyload( + self, + session, + state, + primary_key_identity, + passive, + loadopt, + extra_criteria, + extra_options, + alternate_effective_path, + execution_options, + ): + strategy_options = util.preloaded.orm_strategy_options + + clauseelement = self.entity.__clause_element__() + stmt = Select._create_raw_select( + _raw_columns=[clauseelement], + _propagate_attrs=clauseelement._propagate_attrs, + _label_style=LABEL_STYLE_TABLENAME_PLUS_COL, + _compile_options=ORMCompileState.default_compile_options, + ) + load_options = QueryContext.default_load_options + + load_options += { + "_invoke_all_eagers": False, + "_lazy_loaded_from": state, + } + + if self.parent_property.secondary is not None: + stmt = stmt.select_from( + self.mapper, self.parent_property.secondary + ) + + pending = not state.key + + # don't autoflush on pending + if pending or passive & attributes.NO_AUTOFLUSH: + stmt._execution_options = util.immutabledict({"autoflush": False}) + + use_get = self.use_get + + if state.load_options or (loadopt and loadopt._extra_criteria): + if alternate_effective_path is None: + effective_path = state.load_path[self.parent_property] + else: + effective_path = alternate_effective_path[self.parent_property] + + opts = state.load_options + + if loadopt and loadopt._extra_criteria: + use_get = False + opts += ( + orm_util.LoaderCriteriaOption(self.entity, extra_criteria), + ) + + stmt._with_options = opts + elif alternate_effective_path is None: + # this path is used if there are not already any options + # in the query, but an event may want to add them + effective_path = state.mapper._path_registry[self.parent_property] + else: + # added by immediateloader + effective_path = alternate_effective_path[self.parent_property] + + if extra_options: + stmt._with_options += extra_options + + stmt._compile_options += {"_current_path": effective_path} + + if use_get: + if self._raise_on_sql and not passive & PassiveFlag.NO_RAISE: + self._invoke_raise_load(state, passive, "raise_on_sql") + + return loading.load_on_pk_identity( + session, + stmt, + primary_key_identity, + load_options=load_options, + execution_options=execution_options, + ) + + if self._order_by: + stmt._order_by_clauses = self._order_by + + def _lazyload_reverse(compile_context): + for rev in self.parent_property._reverse_property: + # reverse props that are MANYTOONE are loading *this* + # object from get(), so don't need to eager out to those. + if ( + rev.direction is interfaces.MANYTOONE + and rev._use_get + and not isinstance(rev.strategy, LazyLoader) + ): + strategy_options.Load._construct_for_existing_path( + compile_context.compile_options._current_path[ + rev.parent + ] + ).lazyload(rev).process_compile_state(compile_context) + + stmt._with_context_options += ( + (_lazyload_reverse, self.parent_property), + ) + + lazy_clause, params = self._generate_lazy_clause(state, passive) + + if execution_options: + execution_options = util.EMPTY_DICT.merge_with( + execution_options, + { + "_sa_orm_load_options": load_options, + }, + ) + else: + execution_options = { + "_sa_orm_load_options": load_options, + } + + if ( + self.key in state.dict + and not passive & PassiveFlag.DEFERRED_HISTORY_LOAD + ): + return LoaderCallableStatus.ATTR_WAS_SET + + if pending: + if util.has_intersection(orm_util._none_set, params.values()): + return None + + elif util.has_intersection(orm_util._never_set, params.values()): + return None + + if self._raise_on_sql and not passive & PassiveFlag.NO_RAISE: + self._invoke_raise_load(state, passive, "raise_on_sql") + + stmt._where_criteria = (lazy_clause,) + + result = session.execute( + stmt, params, execution_options=execution_options + ) + + result = result.unique().scalars().all() + + if self.uselist: + return result + else: + l = len(result) + if l: + if l > 1: + util.warn( + "Multiple rows returned with " + "uselist=False for lazily-loaded attribute '%s' " + % self.parent_property + ) + + return result[0] + else: + return None + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + key = self.key + + if ( + context.load_options._is_user_refresh + and context.query._compile_options._only_load_props + and self.key in context.query._compile_options._only_load_props + ): + return self._immediateload_create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + if not self.is_class_level or (loadopt and loadopt._extra_criteria): + # we are not the primary manager for this attribute + # on this class - set up a + # per-instance lazyloader, which will override the + # class-level behavior. + # this currently only happens when using a + # "lazyload" option on a "no load" + # attribute - "eager" attributes always have a + # class-level lazyloader installed. + set_lazy_callable = ( + InstanceState._instance_level_callable_processor + )( + mapper.class_manager, + LoadLazyAttribute( + key, + self, + loadopt, + ( + loadopt._generate_extra_criteria(context) + if loadopt._extra_criteria + else None + ), + ), + key, + ) + + populators["new"].append((self.key, set_lazy_callable)) + elif context.populate_existing or mapper.always_refresh: + + def reset_for_lazy_callable(state, dict_, row): + # we are the primary manager for this attribute on + # this class - reset its + # per-instance attribute state, so that the class-level + # lazy loader is + # executed when next referenced on this instance. + # this is needed in + # populate_existing() types of scenarios to reset + # any existing state. + state._reset(dict_, key) + + populators["new"].append((self.key, reset_for_lazy_callable)) + + +class LoadLazyAttribute: + """semi-serializable loader object used by LazyLoader + + Historically, this object would be carried along with instances that + needed to run lazyloaders, so it had to be serializable to support + cached instances. + + this is no longer a general requirement, and the case where this object + is used is exactly the case where we can't really serialize easily, + which is when extra criteria in the loader option is present. + + We can't reliably serialize that as it refers to mapped entities and + AliasedClass objects that are local to the current process, which would + need to be matched up on deserialize e.g. the sqlalchemy.ext.serializer + approach. + + """ + + def __init__(self, key, initiating_strategy, loadopt, extra_criteria): + self.key = key + self.strategy_key = initiating_strategy.strategy_key + self.loadopt = loadopt + self.extra_criteria = extra_criteria + + def __getstate__(self): + if self.extra_criteria is not None: + util.warn( + "Can't reliably serialize a lazyload() option that " + "contains additional criteria; please use eager loading " + "for this case" + ) + return { + "key": self.key, + "strategy_key": self.strategy_key, + "loadopt": self.loadopt, + "extra_criteria": (), + } + + def __call__(self, state, passive=attributes.PASSIVE_OFF): + key = self.key + instance_mapper = state.manager.mapper + prop = instance_mapper._props[key] + strategy = prop._strategies[self.strategy_key] + + return strategy._load_for_state( + state, + passive, + loadopt=self.loadopt, + extra_criteria=self.extra_criteria, + ) + + +class PostLoader(AbstractRelationshipLoader): + """A relationship loader that emits a second SELECT statement.""" + + __slots__ = () + + def _setup_for_recursion(self, context, path, loadopt, join_depth=None): + effective_path = ( + context.compile_state.current_path or orm_util.PathRegistry.root + ) + path + + top_level_context = context._get_top_level_context() + execution_options = util.immutabledict( + {"sa_top_level_orm_context": top_level_context} + ) + + if loadopt: + recursion_depth = loadopt.local_opts.get("recursion_depth", None) + unlimited_recursion = recursion_depth == -1 + else: + recursion_depth = None + unlimited_recursion = False + + if recursion_depth is not None: + if not self.parent_property._is_self_referential: + raise sa_exc.InvalidRequestError( + f"recursion_depth option on relationship " + f"{self.parent_property} not valid for " + "non-self-referential relationship" + ) + recursion_depth = context.execution_options.get( + f"_recursion_depth_{id(self)}", recursion_depth + ) + + if not unlimited_recursion and recursion_depth < 0: + return ( + effective_path, + False, + execution_options, + recursion_depth, + ) + + if not unlimited_recursion: + execution_options = execution_options.union( + { + f"_recursion_depth_{id(self)}": recursion_depth - 1, + } + ) + + if loading.PostLoad.path_exists( + context, effective_path, self.parent_property + ): + return effective_path, False, execution_options, recursion_depth + + path_w_prop = path[self.parent_property] + effective_path_w_prop = effective_path[self.parent_property] + + if not path_w_prop.contains(context.attributes, "loader"): + if join_depth: + if effective_path_w_prop.length / 2 > join_depth: + return ( + effective_path, + False, + execution_options, + recursion_depth, + ) + elif effective_path_w_prop.contains_mapper(self.mapper): + return ( + effective_path, + False, + execution_options, + recursion_depth, + ) + + return effective_path, True, execution_options, recursion_depth + + +@relationships.RelationshipProperty.strategy_for(lazy="immediate") +class ImmediateLoader(PostLoader): + __slots__ = ("join_depth",) + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.join_depth = self.parent_property.join_depth + + def init_class_attribute(self, mapper): + self.parent_property._get_strategy( + (("lazy", "select"),) + ).init_class_attribute(mapper) + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + ( + effective_path, + run_loader, + execution_options, + recursion_depth, + ) = self._setup_for_recursion(context, path, loadopt, self.join_depth) + if not run_loader: + # this will not emit SQL and will only emit for a many-to-one + # "use get" load. the "_RELATED" part means it may return + # instance even if its expired, since this is a mutually-recursive + # load operation. + flags = attributes.PASSIVE_NO_FETCH_RELATED | PassiveFlag.NO_RAISE + else: + flags = attributes.PASSIVE_OFF | PassiveFlag.NO_RAISE + + loading.PostLoad.callable_for_path( + context, + effective_path, + self.parent, + self.parent_property, + self._load_for_path, + loadopt, + flags, + recursion_depth, + execution_options, + ) + + def _load_for_path( + self, + context, + path, + states, + load_only, + loadopt, + flags, + recursion_depth, + execution_options, + ): + if recursion_depth: + new_opt = Load(loadopt.path.entity) + new_opt.context = ( + loadopt, + loadopt._recurse(), + ) + alternate_effective_path = path._truncate_recursive() + extra_options = (new_opt,) + else: + new_opt = None + alternate_effective_path = path + extra_options = () + + key = self.key + lazyloader = self.parent_property._get_strategy((("lazy", "select"),)) + for state, overwrite in states: + dict_ = state.dict + + if overwrite or key not in dict_: + value = lazyloader._load_for_state( + state, + flags, + extra_options=extra_options, + alternate_effective_path=alternate_effective_path, + execution_options=execution_options, + ) + if value not in ( + ATTR_WAS_SET, + LoaderCallableStatus.PASSIVE_NO_RESULT, + ): + state.get_impl(key).set_committed_value( + state, dict_, value + ) + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(lazy="subquery") +class SubqueryLoader(PostLoader): + __slots__ = ("join_depth",) + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.join_depth = self.parent_property.join_depth + + def init_class_attribute(self, mapper): + self.parent_property._get_strategy( + (("lazy", "select"),) + ).init_class_attribute(mapper) + + def _get_leftmost( + self, + orig_query_entity_index, + subq_path, + current_compile_state, + is_root, + ): + given_subq_path = subq_path + subq_path = subq_path.path + subq_mapper = orm_util._class_to_mapper(subq_path[0]) + + # determine attributes of the leftmost mapper + if ( + self.parent.isa(subq_mapper) + and self.parent_property is subq_path[1] + ): + leftmost_mapper, leftmost_prop = self.parent, self.parent_property + else: + leftmost_mapper, leftmost_prop = subq_mapper, subq_path[1] + + if is_root: + # the subq_path is also coming from cached state, so when we start + # building up this path, it has to also be converted to be in terms + # of the current state. this is for the specific case of the entity + # is an AliasedClass against a subquery that's not otherwise going + # to adapt + new_subq_path = current_compile_state._entities[ + orig_query_entity_index + ].entity_zero._path_registry[leftmost_prop] + additional = len(subq_path) - len(new_subq_path) + if additional: + new_subq_path += path_registry.PathRegistry.coerce( + subq_path[-additional:] + ) + else: + new_subq_path = given_subq_path + + leftmost_cols = leftmost_prop.local_columns + + leftmost_attr = [ + getattr( + new_subq_path.path[0].entity, + leftmost_mapper._columntoproperty[c].key, + ) + for c in leftmost_cols + ] + + return leftmost_mapper, leftmost_attr, leftmost_prop, new_subq_path + + def _generate_from_original_query( + self, + orig_compile_state, + orig_query, + leftmost_mapper, + leftmost_attr, + leftmost_relationship, + orig_entity, + ): + # reformat the original query + # to look only for significant columns + q = orig_query._clone().correlate(None) + + # LEGACY: make a Query back from the select() !! + # This suits at least two legacy cases: + # 1. applications which expect before_compile() to be called + # below when we run .subquery() on this query (Keystone) + # 2. applications which are doing subqueryload with complex + # from_self() queries, as query.subquery() / .statement + # has to do the full compile context for multiply-nested + # from_self() (Neutron) - see test_subqload_from_self + # for demo. + q2 = query.Query.__new__(query.Query) + q2.__dict__.update(q.__dict__) + q = q2 + + # set the query's "FROM" list explicitly to what the + # FROM list would be in any case, as we will be limiting + # the columns in the SELECT list which may no longer include + # all entities mentioned in things like WHERE, JOIN, etc. + if not q._from_obj: + q._enable_assertions = False + q.select_from.non_generative( + q, + *{ + ent["entity"] + for ent in _column_descriptions( + orig_query, compile_state=orig_compile_state + ) + if ent["entity"] is not None + }, + ) + + # select from the identity columns of the outer (specifically, these + # are the 'local_cols' of the property). This will remove other + # columns from the query that might suggest the right entity which is + # why we do set select_from above. The attributes we have are + # coerced and adapted using the original query's adapter, which is + # needed only for the case of adapting a subclass column to + # that of a polymorphic selectable, e.g. we have + # Engineer.primary_language and the entity is Person. All other + # adaptations, e.g. from_self, select_entity_from(), will occur + # within the new query when it compiles, as the compile_state we are + # using here is only a partial one. If the subqueryload is from a + # with_polymorphic() or other aliased() object, left_attr will already + # be the correct attributes so no adaptation is needed. + target_cols = orig_compile_state._adapt_col_list( + [ + sql.coercions.expect(sql.roles.ColumnsClauseRole, o) + for o in leftmost_attr + ], + orig_compile_state._get_current_adapter(), + ) + q._raw_columns = target_cols + + distinct_target_key = leftmost_relationship.distinct_target_key + + if distinct_target_key is True: + q._distinct = True + elif distinct_target_key is None: + # if target_cols refer to a non-primary key or only + # part of a composite primary key, set the q as distinct + for t in {c.table for c in target_cols}: + if not set(target_cols).issuperset(t.primary_key): + q._distinct = True + break + + # don't need ORDER BY if no limit/offset + if not q._has_row_limiting_clause: + q._order_by_clauses = () + + if q._distinct is True and q._order_by_clauses: + # the logic to automatically add the order by columns to the query + # when distinct is True is deprecated in the query + to_add = sql_util.expand_column_list_from_order_by( + target_cols, q._order_by_clauses + ) + if to_add: + q._set_entities(target_cols + to_add) + + # the original query now becomes a subquery + # which we'll join onto. + # LEGACY: as "q" is a Query, the before_compile() event is invoked + # here. + embed_q = q.set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL).subquery() + left_alias = orm_util.AliasedClass( + leftmost_mapper, embed_q, use_mapper_path=True + ) + return left_alias + + def _prep_for_joins(self, left_alias, subq_path): + # figure out what's being joined. a.k.a. the fun part + to_join = [] + pairs = list(subq_path.pairs()) + + for i, (mapper, prop) in enumerate(pairs): + if i > 0: + # look at the previous mapper in the chain - + # if it is as or more specific than this prop's + # mapper, use that instead. + # note we have an assumption here that + # the non-first element is always going to be a mapper, + # not an AliasedClass + + prev_mapper = pairs[i - 1][1].mapper + to_append = prev_mapper if prev_mapper.isa(mapper) else mapper + else: + to_append = mapper + + to_join.append((to_append, prop.key)) + + # determine the immediate parent class we are joining from, + # which needs to be aliased. + + if len(to_join) < 2: + # in the case of a one level eager load, this is the + # leftmost "left_alias". + parent_alias = left_alias + else: + info = inspect(to_join[-1][0]) + if info.is_aliased_class: + parent_alias = info.entity + else: + # alias a plain mapper as we may be + # joining multiple times + parent_alias = orm_util.AliasedClass( + info.entity, use_mapper_path=True + ) + + local_cols = self.parent_property.local_columns + + local_attr = [ + getattr(parent_alias, self.parent._columntoproperty[c].key) + for c in local_cols + ] + return to_join, local_attr, parent_alias + + def _apply_joins( + self, q, to_join, left_alias, parent_alias, effective_entity + ): + ltj = len(to_join) + if ltj == 1: + to_join = [ + getattr(left_alias, to_join[0][1]).of_type(effective_entity) + ] + elif ltj == 2: + to_join = [ + getattr(left_alias, to_join[0][1]).of_type(parent_alias), + getattr(parent_alias, to_join[-1][1]).of_type( + effective_entity + ), + ] + elif ltj > 2: + middle = [ + ( + ( + orm_util.AliasedClass(item[0]) + if not inspect(item[0]).is_aliased_class + else item[0].entity + ), + item[1], + ) + for item in to_join[1:-1] + ] + inner = [] + + while middle: + item = middle.pop(0) + attr = getattr(item[0], item[1]) + if middle: + attr = attr.of_type(middle[0][0]) + else: + attr = attr.of_type(parent_alias) + + inner.append(attr) + + to_join = ( + [getattr(left_alias, to_join[0][1]).of_type(inner[0].parent)] + + inner + + [ + getattr(parent_alias, to_join[-1][1]).of_type( + effective_entity + ) + ] + ) + + for attr in to_join: + q = q.join(attr) + + return q + + def _setup_options( + self, + context, + q, + subq_path, + rewritten_path, + orig_query, + effective_entity, + loadopt, + ): + # note that because the subqueryload object + # does not re-use the cached query, instead always making + # use of the current invoked query, while we have two queries + # here (orig and context.query), they are both non-cached + # queries and we can transfer the options as is without + # adjusting for new criteria. Some work on #6881 / #6889 + # brought this into question. + new_options = orig_query._with_options + + if loadopt and loadopt._extra_criteria: + new_options += ( + orm_util.LoaderCriteriaOption( + self.entity, + loadopt._generate_extra_criteria(context), + ), + ) + + # propagate loader options etc. to the new query. + # these will fire relative to subq_path. + q = q._with_current_path(rewritten_path) + q = q.options(*new_options) + + return q + + def _setup_outermost_orderby(self, q): + if self.parent_property.order_by: + + def _setup_outermost_orderby(compile_context): + compile_context.eager_order_by += tuple( + util.to_list(self.parent_property.order_by) + ) + + q = q._add_context_option( + _setup_outermost_orderby, self.parent_property + ) + + return q + + class _SubqCollections: + """Given a :class:`_query.Query` used to emit the "subquery load", + provide a load interface that executes the query at the + first moment a value is needed. + + """ + + __slots__ = ( + "session", + "execution_options", + "load_options", + "params", + "subq", + "_data", + ) + + def __init__(self, context, subq): + # avoid creating a cycle by storing context + # even though that's preferable + self.session = context.session + self.execution_options = context.execution_options + self.load_options = context.load_options + self.params = context.params or {} + self.subq = subq + self._data = None + + def get(self, key, default): + if self._data is None: + self._load() + return self._data.get(key, default) + + def _load(self): + self._data = collections.defaultdict(list) + + q = self.subq + assert q.session is None + + q = q.with_session(self.session) + + if self.load_options._populate_existing: + q = q.populate_existing() + # to work with baked query, the parameters may have been + # updated since this query was created, so take these into account + + rows = list(q.params(self.params)) + for k, v in itertools.groupby(rows, lambda x: x[1:]): + self._data[k].extend(vv[0] for vv in v) + + def loader(self, state, dict_, row): + if self._data is None: + self._load() + + def _setup_query_from_rowproc( + self, + context, + query_entity, + path, + entity, + loadopt, + adapter, + ): + compile_state = context.compile_state + if ( + not compile_state.compile_options._enable_eagerloads + or compile_state.compile_options._for_refresh_state + ): + return + + orig_query_entity_index = compile_state._entities.index(query_entity) + context.loaders_require_buffering = True + + path = path[self.parent_property] + + # build up a path indicating the path from the leftmost + # entity to the thing we're subquery loading. + with_poly_entity = path.get( + compile_state.attributes, "path_with_polymorphic", None + ) + if with_poly_entity is not None: + effective_entity = with_poly_entity + else: + effective_entity = self.entity + + subq_path, rewritten_path = context.query._execution_options.get( + ("subquery_paths", None), + (orm_util.PathRegistry.root, orm_util.PathRegistry.root), + ) + is_root = subq_path is orm_util.PathRegistry.root + subq_path = subq_path + path + rewritten_path = rewritten_path + path + + # use the current query being invoked, not the compile state + # one. this is so that we get the current parameters. however, + # it means we can't use the existing compile state, we have to make + # a new one. other approaches include possibly using the + # compiled query but swapping the params, seems only marginally + # less time spent but more complicated + orig_query = context.query._execution_options.get( + ("orig_query", SubqueryLoader), context.query + ) + + # make a new compile_state for the query that's probably cached, but + # we're sort of undoing a bit of that caching :( + compile_state_cls = ORMCompileState._get_plugin_class_for_plugin( + orig_query, "orm" + ) + + if orig_query._is_lambda_element: + if context.load_options._lazy_loaded_from is None: + util.warn( + 'subqueryloader for "%s" must invoke lambda callable ' + "at %r in " + "order to produce a new query, decreasing the efficiency " + "of caching for this statement. Consider using " + "selectinload() for more effective full-lambda caching" + % (self, orig_query) + ) + orig_query = orig_query._resolved + + # this is the more "quick" version, however it's not clear how + # much of this we need. in particular I can't get a test to + # fail if the "set_base_alias" is missing and not sure why that is. + orig_compile_state = compile_state_cls._create_entities_collection( + orig_query, legacy=False + ) + + ( + leftmost_mapper, + leftmost_attr, + leftmost_relationship, + rewritten_path, + ) = self._get_leftmost( + orig_query_entity_index, + rewritten_path, + orig_compile_state, + is_root, + ) + + # generate a new Query from the original, then + # produce a subquery from it. + left_alias = self._generate_from_original_query( + orig_compile_state, + orig_query, + leftmost_mapper, + leftmost_attr, + leftmost_relationship, + entity, + ) + + # generate another Query that will join the + # left alias to the target relationships. + # basically doing a longhand + # "from_self()". (from_self() itself not quite industrial + # strength enough for all contingencies...but very close) + + q = query.Query(effective_entity) + + q._execution_options = context.query._execution_options.merge_with( + context.execution_options, + { + ("orig_query", SubqueryLoader): orig_query, + ("subquery_paths", None): (subq_path, rewritten_path), + }, + ) + + q = q._set_enable_single_crit(False) + to_join, local_attr, parent_alias = self._prep_for_joins( + left_alias, subq_path + ) + + q = q.add_columns(*local_attr) + q = self._apply_joins( + q, to_join, left_alias, parent_alias, effective_entity + ) + + q = self._setup_options( + context, + q, + subq_path, + rewritten_path, + orig_query, + effective_entity, + loadopt, + ) + q = self._setup_outermost_orderby(q) + + return q + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + if context.refresh_state: + return self._immediateload_create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + _, run_loader, _, _ = self._setup_for_recursion( + context, path, loadopt, self.join_depth + ) + if not run_loader: + return + + if not isinstance(context.compile_state, ORMSelectCompileState): + # issue 7505 - subqueryload() in 1.3 and previous would silently + # degrade for from_statement() without warning. this behavior + # is restored here + return + + if not self.parent.class_manager[self.key].impl.supports_population: + raise sa_exc.InvalidRequestError( + "'%s' does not support object " + "population - eager loading cannot be applied." % self + ) + + # a little dance here as the "path" is still something that only + # semi-tracks the exact series of things we are loading, still not + # telling us about with_polymorphic() and stuff like that when it's at + # the root.. the initial MapperEntity is more accurate for this case. + if len(path) == 1: + if not orm_util._entity_isa(query_entity.entity_zero, self.parent): + return + elif not orm_util._entity_isa(path[-1], self.parent): + return + + subq = self._setup_query_from_rowproc( + context, + query_entity, + path, + path[-1], + loadopt, + adapter, + ) + + if subq is None: + return + + assert subq.session is None + + path = path[self.parent_property] + + local_cols = self.parent_property.local_columns + + # cache the loaded collections in the context + # so that inheriting mappers don't re-load when they + # call upon create_row_processor again + collections = path.get(context.attributes, "collections") + if collections is None: + collections = self._SubqCollections(context, subq) + path.set(context.attributes, "collections", collections) + + if adapter: + local_cols = [adapter.columns[c] for c in local_cols] + + if self.uselist: + self._create_collection_loader( + context, result, collections, local_cols, populators + ) + else: + self._create_scalar_loader( + context, result, collections, local_cols, populators + ) + + def _create_collection_loader( + self, context, result, collections, local_cols, populators + ): + tuple_getter = result._tuple_getter(local_cols) + + def load_collection_from_subq(state, dict_, row): + collection = collections.get(tuple_getter(row), ()) + state.get_impl(self.key).set_committed_value( + state, dict_, collection + ) + + def load_collection_from_subq_existing_row(state, dict_, row): + if self.key not in dict_: + load_collection_from_subq(state, dict_, row) + + populators["new"].append((self.key, load_collection_from_subq)) + populators["existing"].append( + (self.key, load_collection_from_subq_existing_row) + ) + + if context.invoke_all_eagers: + populators["eager"].append((self.key, collections.loader)) + + def _create_scalar_loader( + self, context, result, collections, local_cols, populators + ): + tuple_getter = result._tuple_getter(local_cols) + + def load_scalar_from_subq(state, dict_, row): + collection = collections.get(tuple_getter(row), (None,)) + if len(collection) > 1: + util.warn( + "Multiple rows returned with " + "uselist=False for eagerly-loaded attribute '%s' " % self + ) + + scalar = collection[0] + state.get_impl(self.key).set_committed_value(state, dict_, scalar) + + def load_scalar_from_subq_existing_row(state, dict_, row): + if self.key not in dict_: + load_scalar_from_subq(state, dict_, row) + + populators["new"].append((self.key, load_scalar_from_subq)) + populators["existing"].append( + (self.key, load_scalar_from_subq_existing_row) + ) + if context.invoke_all_eagers: + populators["eager"].append((self.key, collections.loader)) + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(lazy="joined") +@relationships.RelationshipProperty.strategy_for(lazy=False) +class JoinedLoader(AbstractRelationshipLoader): + """Provide loading behavior for a :class:`.Relationship` + using joined eager loading. + + """ + + __slots__ = "join_depth" + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.join_depth = self.parent_property.join_depth + + def init_class_attribute(self, mapper): + self.parent_property._get_strategy( + (("lazy", "select"),) + ).init_class_attribute(mapper) + + def setup_query( + self, + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection=None, + parentmapper=None, + chained_from_outerjoin=False, + **kwargs, + ): + """Add a left outer join to the statement that's being constructed.""" + + if not compile_state.compile_options._enable_eagerloads: + return + elif self.uselist: + compile_state.multi_row_eager_loaders = True + + path = path[self.parent_property] + + with_polymorphic = None + + user_defined_adapter = ( + self._init_user_defined_eager_proc( + loadopt, compile_state, compile_state.attributes + ) + if loadopt + else False + ) + + if user_defined_adapter is not False: + # setup an adapter but dont create any JOIN, assume it's already + # in the query + ( + clauses, + adapter, + add_to_collection, + ) = self._setup_query_on_user_defined_adapter( + compile_state, + query_entity, + path, + adapter, + user_defined_adapter, + ) + + # don't do "wrap" for multi-row, we want to wrap + # limited/distinct SELECT, + # because we want to put the JOIN on the outside. + + else: + # if not via query option, check for + # a cycle + if not path.contains(compile_state.attributes, "loader"): + if self.join_depth: + if path.length / 2 > self.join_depth: + return + elif path.contains_mapper(self.mapper): + return + + # add the JOIN and create an adapter + ( + clauses, + adapter, + add_to_collection, + chained_from_outerjoin, + ) = self._generate_row_adapter( + compile_state, + query_entity, + path, + loadopt, + adapter, + column_collection, + parentmapper, + chained_from_outerjoin, + ) + + # for multi-row, we want to wrap limited/distinct SELECT, + # because we want to put the JOIN on the outside. + compile_state.eager_adding_joins = True + + with_poly_entity = path.get( + compile_state.attributes, "path_with_polymorphic", None + ) + if with_poly_entity is not None: + with_polymorphic = inspect( + with_poly_entity + ).with_polymorphic_mappers + else: + with_polymorphic = None + + path = path[self.entity] + + loading._setup_entity_query( + compile_state, + self.mapper, + query_entity, + path, + clauses, + add_to_collection, + with_polymorphic=with_polymorphic, + parentmapper=self.mapper, + chained_from_outerjoin=chained_from_outerjoin, + ) + + has_nones = util.NONE_SET.intersection(compile_state.secondary_columns) + + if has_nones: + if with_poly_entity is not None: + raise sa_exc.InvalidRequestError( + "Detected unaliased columns when generating joined " + "load. Make sure to use aliased=True or flat=True " + "when using joined loading with with_polymorphic()." + ) + else: + compile_state.secondary_columns = [ + c for c in compile_state.secondary_columns if c is not None + ] + + def _init_user_defined_eager_proc( + self, loadopt, compile_state, target_attributes + ): + # check if the opt applies at all + if "eager_from_alias" not in loadopt.local_opts: + # nope + return False + + path = loadopt.path.parent + + # the option applies. check if the "user_defined_eager_row_processor" + # has been built up. + adapter = path.get( + compile_state.attributes, "user_defined_eager_row_processor", False + ) + if adapter is not False: + # just return it + return adapter + + # otherwise figure it out. + alias = loadopt.local_opts["eager_from_alias"] + root_mapper, prop = path[-2:] + + if alias is not None: + if isinstance(alias, str): + alias = prop.target.alias(alias) + adapter = orm_util.ORMAdapter( + orm_util._TraceAdaptRole.JOINEDLOAD_USER_DEFINED_ALIAS, + prop.mapper, + selectable=alias, + equivalents=prop.mapper._equivalent_columns, + limit_on_entity=False, + ) + else: + if path.contains( + compile_state.attributes, "path_with_polymorphic" + ): + with_poly_entity = path.get( + compile_state.attributes, "path_with_polymorphic" + ) + adapter = orm_util.ORMAdapter( + orm_util._TraceAdaptRole.JOINEDLOAD_PATH_WITH_POLYMORPHIC, + with_poly_entity, + equivalents=prop.mapper._equivalent_columns, + ) + else: + adapter = compile_state._polymorphic_adapters.get( + prop.mapper, None + ) + path.set( + target_attributes, + "user_defined_eager_row_processor", + adapter, + ) + + return adapter + + def _setup_query_on_user_defined_adapter( + self, context, entity, path, adapter, user_defined_adapter + ): + # apply some more wrapping to the "user defined adapter" + # if we are setting up the query for SQL render. + adapter = entity._get_entity_clauses(context) + + if adapter and user_defined_adapter: + user_defined_adapter = user_defined_adapter.wrap(adapter) + path.set( + context.attributes, + "user_defined_eager_row_processor", + user_defined_adapter, + ) + elif adapter: + user_defined_adapter = adapter + path.set( + context.attributes, + "user_defined_eager_row_processor", + user_defined_adapter, + ) + + add_to_collection = context.primary_columns + return user_defined_adapter, adapter, add_to_collection + + def _generate_row_adapter( + self, + compile_state, + entity, + path, + loadopt, + adapter, + column_collection, + parentmapper, + chained_from_outerjoin, + ): + with_poly_entity = path.get( + compile_state.attributes, "path_with_polymorphic", None + ) + if with_poly_entity: + to_adapt = with_poly_entity + else: + insp = inspect(self.entity) + if insp.is_aliased_class: + alt_selectable = insp.selectable + else: + alt_selectable = None + + to_adapt = orm_util.AliasedClass( + self.mapper, + alias=( + alt_selectable._anonymous_fromclause(flat=True) + if alt_selectable is not None + else None + ), + flat=True, + use_mapper_path=True, + ) + + to_adapt_insp = inspect(to_adapt) + + clauses = to_adapt_insp._memo( + ("joinedloader_ormadapter", self), + orm_util.ORMAdapter, + orm_util._TraceAdaptRole.JOINEDLOAD_MEMOIZED_ADAPTER, + to_adapt_insp, + equivalents=self.mapper._equivalent_columns, + adapt_required=True, + allow_label_resolve=False, + anonymize_labels=True, + ) + + assert clauses.is_aliased_class + + innerjoin = ( + loadopt.local_opts.get("innerjoin", self.parent_property.innerjoin) + if loadopt is not None + else self.parent_property.innerjoin + ) + + if not innerjoin: + # if this is an outer join, all non-nested eager joins from + # this path must also be outer joins + chained_from_outerjoin = True + + compile_state.create_eager_joins.append( + ( + self._create_eager_join, + entity, + path, + adapter, + parentmapper, + clauses, + innerjoin, + chained_from_outerjoin, + loadopt._extra_criteria if loadopt else (), + ) + ) + + add_to_collection = compile_state.secondary_columns + path.set(compile_state.attributes, "eager_row_processor", clauses) + + return clauses, adapter, add_to_collection, chained_from_outerjoin + + def _create_eager_join( + self, + compile_state, + query_entity, + path, + adapter, + parentmapper, + clauses, + innerjoin, + chained_from_outerjoin, + extra_criteria, + ): + if parentmapper is None: + localparent = query_entity.mapper + else: + localparent = parentmapper + + # whether or not the Query will wrap the selectable in a subquery, + # and then attach eager load joins to that (i.e., in the case of + # LIMIT/OFFSET etc.) + should_nest_selectable = ( + compile_state.multi_row_eager_loaders + and compile_state._should_nest_selectable + ) + + query_entity_key = None + + if ( + query_entity not in compile_state.eager_joins + and not should_nest_selectable + and compile_state.from_clauses + ): + indexes = sql_util.find_left_clause_that_matches_given( + compile_state.from_clauses, query_entity.selectable + ) + + if len(indexes) > 1: + # for the eager load case, I can't reproduce this right + # now. For query.join() I can. + raise sa_exc.InvalidRequestError( + "Can't identify which query entity in which to joined " + "eager load from. Please use an exact match when " + "specifying the join path." + ) + + if indexes: + clause = compile_state.from_clauses[indexes[0]] + # join to an existing FROM clause on the query. + # key it to its list index in the eager_joins dict. + # Query._compile_context will adapt as needed and + # append to the FROM clause of the select(). + query_entity_key, default_towrap = indexes[0], clause + + if query_entity_key is None: + query_entity_key, default_towrap = ( + query_entity, + query_entity.selectable, + ) + + towrap = compile_state.eager_joins.setdefault( + query_entity_key, default_towrap + ) + + if adapter: + if getattr(adapter, "is_aliased_class", False): + # joining from an adapted entity. The adapted entity + # might be a "with_polymorphic", so resolve that to our + # specific mapper's entity before looking for our attribute + # name on it. + efm = adapter.aliased_insp._entity_for_mapper( + localparent + if localparent.isa(self.parent) + else self.parent + ) + + # look for our attribute on the adapted entity, else fall back + # to our straight property + onclause = getattr(efm.entity, self.key, self.parent_property) + else: + onclause = getattr( + orm_util.AliasedClass( + self.parent, adapter.selectable, use_mapper_path=True + ), + self.key, + self.parent_property, + ) + + else: + onclause = self.parent_property + + assert clauses.is_aliased_class + + attach_on_outside = ( + not chained_from_outerjoin + or not innerjoin + or innerjoin == "unnested" + or query_entity.entity_zero.represents_outer_join + ) + + extra_join_criteria = extra_criteria + additional_entity_criteria = compile_state.global_attributes.get( + ("additional_entity_criteria", self.mapper), () + ) + if additional_entity_criteria: + extra_join_criteria += tuple( + ae._resolve_where_criteria(self.mapper) + for ae in additional_entity_criteria + if ae.propagate_to_loaders + ) + + if attach_on_outside: + # this is the "classic" eager join case. + eagerjoin = orm_util._ORMJoin( + towrap, + clauses.aliased_insp, + onclause, + isouter=not innerjoin + or query_entity.entity_zero.represents_outer_join + or (chained_from_outerjoin and isinstance(towrap, sql.Join)), + _left_memo=self.parent, + _right_memo=self.mapper, + _extra_criteria=extra_join_criteria, + ) + else: + # all other cases are innerjoin=='nested' approach + eagerjoin = self._splice_nested_inner_join( + path, towrap, clauses, onclause, extra_join_criteria + ) + + compile_state.eager_joins[query_entity_key] = eagerjoin + + # send a hint to the Query as to where it may "splice" this join + eagerjoin.stop_on = query_entity.selectable + + if not parentmapper: + # for parentclause that is the non-eager end of the join, + # ensure all the parent cols in the primaryjoin are actually + # in the + # columns clause (i.e. are not deferred), so that aliasing applied + # by the Query propagates those columns outward. + # This has the effect + # of "undefering" those columns. + for col in sql_util._find_columns( + self.parent_property.primaryjoin + ): + if localparent.persist_selectable.c.contains_column(col): + if adapter: + col = adapter.columns[col] + compile_state._append_dedupe_col_collection( + col, compile_state.primary_columns + ) + + if self.parent_property.order_by: + compile_state.eager_order_by += tuple( + (eagerjoin._target_adapter.copy_and_process)( + util.to_list(self.parent_property.order_by) + ) + ) + + def _splice_nested_inner_join( + self, path, join_obj, clauses, onclause, extra_criteria, splicing=False + ): + # recursive fn to splice a nested join into an existing one. + # splicing=False means this is the outermost call, and it + # should return a value. splicing=<from object> is the recursive + # form, where it can return None to indicate the end of the recursion + + if splicing is False: + # first call is always handed a join object + # from the outside + assert isinstance(join_obj, orm_util._ORMJoin) + elif isinstance(join_obj, sql.selectable.FromGrouping): + return self._splice_nested_inner_join( + path, + join_obj.element, + clauses, + onclause, + extra_criteria, + splicing, + ) + elif not isinstance(join_obj, orm_util._ORMJoin): + if path[-2].isa(splicing): + return orm_util._ORMJoin( + join_obj, + clauses.aliased_insp, + onclause, + isouter=False, + _left_memo=splicing, + _right_memo=path[-1].mapper, + _extra_criteria=extra_criteria, + ) + else: + return None + + target_join = self._splice_nested_inner_join( + path, + join_obj.right, + clauses, + onclause, + extra_criteria, + join_obj._right_memo, + ) + if target_join is None: + right_splice = False + target_join = self._splice_nested_inner_join( + path, + join_obj.left, + clauses, + onclause, + extra_criteria, + join_obj._left_memo, + ) + if target_join is None: + # should only return None when recursively called, + # e.g. splicing refers to a from obj + assert ( + splicing is not False + ), "assertion failed attempting to produce joined eager loads" + return None + else: + right_splice = True + + if right_splice: + # for a right splice, attempt to flatten out + # a JOIN b JOIN c JOIN .. to avoid needless + # parenthesis nesting + if not join_obj.isouter and not target_join.isouter: + eagerjoin = join_obj._splice_into_center(target_join) + else: + eagerjoin = orm_util._ORMJoin( + join_obj.left, + target_join, + join_obj.onclause, + isouter=join_obj.isouter, + _left_memo=join_obj._left_memo, + ) + else: + eagerjoin = orm_util._ORMJoin( + target_join, + join_obj.right, + join_obj.onclause, + isouter=join_obj.isouter, + _right_memo=join_obj._right_memo, + ) + + eagerjoin._target_adapter = target_join._target_adapter + return eagerjoin + + def _create_eager_adapter(self, context, result, adapter, path, loadopt): + compile_state = context.compile_state + + user_defined_adapter = ( + self._init_user_defined_eager_proc( + loadopt, compile_state, context.attributes + ) + if loadopt + else False + ) + + if user_defined_adapter is not False: + decorator = user_defined_adapter + # user defined eagerloads are part of the "primary" + # portion of the load. + # the adapters applied to the Query should be honored. + if compile_state.compound_eager_adapter and decorator: + decorator = decorator.wrap( + compile_state.compound_eager_adapter + ) + elif compile_state.compound_eager_adapter: + decorator = compile_state.compound_eager_adapter + else: + decorator = path.get( + compile_state.attributes, "eager_row_processor" + ) + if decorator is None: + return False + + if self.mapper._result_has_identity_key(result, decorator): + return decorator + else: + # no identity key - don't return a row + # processor, will cause a degrade to lazy + return False + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + if not self.parent.class_manager[self.key].impl.supports_population: + raise sa_exc.InvalidRequestError( + "'%s' does not support object " + "population - eager loading cannot be applied." % self + ) + + if self.uselist: + context.loaders_require_uniquing = True + + our_path = path[self.parent_property] + + eager_adapter = self._create_eager_adapter( + context, result, adapter, our_path, loadopt + ) + + if eager_adapter is not False: + key = self.key + + _instance = loading._instance_processor( + query_entity, + self.mapper, + context, + result, + our_path[self.entity], + eager_adapter, + ) + + if not self.uselist: + self._create_scalar_loader(context, key, _instance, populators) + else: + self._create_collection_loader( + context, key, _instance, populators + ) + else: + self.parent_property._get_strategy( + (("lazy", "select"),) + ).create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + def _create_collection_loader(self, context, key, _instance, populators): + def load_collection_from_joined_new_row(state, dict_, row): + # note this must unconditionally clear out any existing collection. + # an existing collection would be present only in the case of + # populate_existing(). + collection = attributes.init_state_collection(state, dict_, key) + result_list = util.UniqueAppender( + collection, "append_without_event" + ) + context.attributes[(state, key)] = result_list + inst = _instance(row) + if inst is not None: + result_list.append(inst) + + def load_collection_from_joined_existing_row(state, dict_, row): + if (state, key) in context.attributes: + result_list = context.attributes[(state, key)] + else: + # appender_key can be absent from context.attributes + # with isnew=False when self-referential eager loading + # is used; the same instance may be present in two + # distinct sets of result columns + collection = attributes.init_state_collection( + state, dict_, key + ) + result_list = util.UniqueAppender( + collection, "append_without_event" + ) + context.attributes[(state, key)] = result_list + inst = _instance(row) + if inst is not None: + result_list.append(inst) + + def load_collection_from_joined_exec(state, dict_, row): + _instance(row) + + populators["new"].append( + (self.key, load_collection_from_joined_new_row) + ) + populators["existing"].append( + (self.key, load_collection_from_joined_existing_row) + ) + if context.invoke_all_eagers: + populators["eager"].append( + (self.key, load_collection_from_joined_exec) + ) + + def _create_scalar_loader(self, context, key, _instance, populators): + def load_scalar_from_joined_new_row(state, dict_, row): + # set a scalar object instance directly on the parent + # object, bypassing InstrumentedAttribute event handlers. + dict_[key] = _instance(row) + + def load_scalar_from_joined_existing_row(state, dict_, row): + # call _instance on the row, even though the object has + # been created, so that we further descend into properties + existing = _instance(row) + + # conflicting value already loaded, this shouldn't happen + if key in dict_: + if existing is not dict_[key]: + util.warn( + "Multiple rows returned with " + "uselist=False for eagerly-loaded attribute '%s' " + % self + ) + else: + # this case is when one row has multiple loads of the + # same entity (e.g. via aliasing), one has an attribute + # that the other doesn't. + dict_[key] = existing + + def load_scalar_from_joined_exec(state, dict_, row): + _instance(row) + + populators["new"].append((self.key, load_scalar_from_joined_new_row)) + populators["existing"].append( + (self.key, load_scalar_from_joined_existing_row) + ) + if context.invoke_all_eagers: + populators["eager"].append( + (self.key, load_scalar_from_joined_exec) + ) + + +@log.class_logger +@relationships.RelationshipProperty.strategy_for(lazy="selectin") +class SelectInLoader(PostLoader, util.MemoizedSlots): + __slots__ = ( + "join_depth", + "omit_join", + "_parent_alias", + "_query_info", + "_fallback_query_info", + ) + + query_info = collections.namedtuple( + "queryinfo", + [ + "load_only_child", + "load_with_join", + "in_expr", + "pk_cols", + "zero_idx", + "child_lookup_cols", + ], + ) + + _chunksize = 500 + + def __init__(self, parent, strategy_key): + super().__init__(parent, strategy_key) + self.join_depth = self.parent_property.join_depth + is_m2o = self.parent_property.direction is interfaces.MANYTOONE + + if self.parent_property.omit_join is not None: + self.omit_join = self.parent_property.omit_join + else: + lazyloader = self.parent_property._get_strategy( + (("lazy", "select"),) + ) + if is_m2o: + self.omit_join = lazyloader.use_get + else: + self.omit_join = self.parent._get_clause[0].compare( + lazyloader._rev_lazywhere, + use_proxies=True, + compare_keys=False, + equivalents=self.parent._equivalent_columns, + ) + + if self.omit_join: + if is_m2o: + self._query_info = self._init_for_omit_join_m2o() + self._fallback_query_info = self._init_for_join() + else: + self._query_info = self._init_for_omit_join() + else: + self._query_info = self._init_for_join() + + def _init_for_omit_join(self): + pk_to_fk = dict( + self.parent_property._join_condition.local_remote_pairs + ) + pk_to_fk.update( + (equiv, pk_to_fk[k]) + for k in list(pk_to_fk) + for equiv in self.parent._equivalent_columns.get(k, ()) + ) + + pk_cols = fk_cols = [ + pk_to_fk[col] for col in self.parent.primary_key if col in pk_to_fk + ] + if len(fk_cols) > 1: + in_expr = sql.tuple_(*fk_cols) + zero_idx = False + else: + in_expr = fk_cols[0] + zero_idx = True + + return self.query_info(False, False, in_expr, pk_cols, zero_idx, None) + + def _init_for_omit_join_m2o(self): + pk_cols = self.mapper.primary_key + if len(pk_cols) > 1: + in_expr = sql.tuple_(*pk_cols) + zero_idx = False + else: + in_expr = pk_cols[0] + zero_idx = True + + lazyloader = self.parent_property._get_strategy((("lazy", "select"),)) + lookup_cols = [lazyloader._equated_columns[pk] for pk in pk_cols] + + return self.query_info( + True, False, in_expr, pk_cols, zero_idx, lookup_cols + ) + + def _init_for_join(self): + self._parent_alias = AliasedClass(self.parent.class_) + pa_insp = inspect(self._parent_alias) + pk_cols = [ + pa_insp._adapt_element(col) for col in self.parent.primary_key + ] + if len(pk_cols) > 1: + in_expr = sql.tuple_(*pk_cols) + zero_idx = False + else: + in_expr = pk_cols[0] + zero_idx = True + return self.query_info(False, True, in_expr, pk_cols, zero_idx, None) + + def init_class_attribute(self, mapper): + self.parent_property._get_strategy( + (("lazy", "select"),) + ).init_class_attribute(mapper) + + def create_row_processor( + self, + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ): + if context.refresh_state: + return self._immediateload_create_row_processor( + context, + query_entity, + path, + loadopt, + mapper, + result, + adapter, + populators, + ) + + ( + effective_path, + run_loader, + execution_options, + recursion_depth, + ) = self._setup_for_recursion( + context, path, loadopt, join_depth=self.join_depth + ) + + if not run_loader: + return + + if not self.parent.class_manager[self.key].impl.supports_population: + raise sa_exc.InvalidRequestError( + "'%s' does not support object " + "population - eager loading cannot be applied." % self + ) + + # a little dance here as the "path" is still something that only + # semi-tracks the exact series of things we are loading, still not + # telling us about with_polymorphic() and stuff like that when it's at + # the root.. the initial MapperEntity is more accurate for this case. + if len(path) == 1: + if not orm_util._entity_isa(query_entity.entity_zero, self.parent): + return + elif not orm_util._entity_isa(path[-1], self.parent): + return + + selectin_path = effective_path + + path_w_prop = path[self.parent_property] + + # build up a path indicating the path from the leftmost + # entity to the thing we're subquery loading. + with_poly_entity = path_w_prop.get( + context.attributes, "path_with_polymorphic", None + ) + if with_poly_entity is not None: + effective_entity = inspect(with_poly_entity) + else: + effective_entity = self.entity + + loading.PostLoad.callable_for_path( + context, + selectin_path, + self.parent, + self.parent_property, + self._load_for_path, + effective_entity, + loadopt, + recursion_depth, + execution_options, + ) + + def _load_for_path( + self, + context, + path, + states, + load_only, + effective_entity, + loadopt, + recursion_depth, + execution_options, + ): + if load_only and self.key not in load_only: + return + + query_info = self._query_info + + if query_info.load_only_child: + our_states = collections.defaultdict(list) + none_states = [] + + mapper = self.parent + + for state, overwrite in states: + state_dict = state.dict + related_ident = tuple( + mapper._get_state_attr_by_column( + state, + state_dict, + lk, + passive=attributes.PASSIVE_NO_FETCH, + ) + for lk in query_info.child_lookup_cols + ) + # if the loaded parent objects do not have the foreign key + # to the related item loaded, then degrade into the joined + # version of selectinload + if LoaderCallableStatus.PASSIVE_NO_RESULT in related_ident: + query_info = self._fallback_query_info + break + + # organize states into lists keyed to particular foreign + # key values. + if None not in related_ident: + our_states[related_ident].append( + (state, state_dict, overwrite) + ) + else: + # For FK values that have None, add them to a + # separate collection that will be populated separately + none_states.append((state, state_dict, overwrite)) + + # note the above conditional may have changed query_info + if not query_info.load_only_child: + our_states = [ + (state.key[1], state, state.dict, overwrite) + for state, overwrite in states + ] + + pk_cols = query_info.pk_cols + in_expr = query_info.in_expr + + if not query_info.load_with_join: + # in "omit join" mode, the primary key column and the + # "in" expression are in terms of the related entity. So + # if the related entity is polymorphic or otherwise aliased, + # we need to adapt our "pk_cols" and "in_expr" to that + # entity. in non-"omit join" mode, these are against the + # parent entity and do not need adaption. + if effective_entity.is_aliased_class: + pk_cols = [ + effective_entity._adapt_element(col) for col in pk_cols + ] + in_expr = effective_entity._adapt_element(in_expr) + + bundle_ent = orm_util.Bundle("pk", *pk_cols) + bundle_sql = bundle_ent.__clause_element__() + + entity_sql = effective_entity.__clause_element__() + q = Select._create_raw_select( + _raw_columns=[bundle_sql, entity_sql], + _label_style=LABEL_STYLE_TABLENAME_PLUS_COL, + _compile_options=ORMCompileState.default_compile_options, + _propagate_attrs={ + "compile_state_plugin": "orm", + "plugin_subject": effective_entity, + }, + ) + + if not query_info.load_with_join: + # the Bundle we have in the "omit_join" case is against raw, non + # annotated columns, so to ensure the Query knows its primary + # entity, we add it explicitly. If we made the Bundle against + # annotated columns, we hit a performance issue in this specific + # case, which is detailed in issue #4347. + q = q.select_from(effective_entity) + else: + # in the non-omit_join case, the Bundle is against the annotated/ + # mapped column of the parent entity, but the #4347 issue does not + # occur in this case. + q = q.select_from(self._parent_alias).join( + getattr(self._parent_alias, self.parent_property.key).of_type( + effective_entity + ) + ) + + q = q.filter(in_expr.in_(sql.bindparam("primary_keys"))) + + # a test which exercises what these comments talk about is + # test_selectin_relations.py -> test_twolevel_selectin_w_polymorphic + # + # effective_entity above is given to us in terms of the cached + # statement, namely this one: + orig_query = context.compile_state.select_statement + + # the actual statement that was requested is this one: + # context_query = context.query + # + # that's not the cached one, however. So while it is of the identical + # structure, if it has entities like AliasedInsp, which we get from + # aliased() or with_polymorphic(), the AliasedInsp will likely be a + # different object identity each time, and will not match up + # hashing-wise to the corresponding AliasedInsp that's in the + # cached query, meaning it won't match on paths and loader lookups + # and loaders like this one will be skipped if it is used in options. + # + # as it turns out, standard loader options like selectinload(), + # lazyload() that have a path need + # to come from the cached query so that the AliasedInsp etc. objects + # that are in the query line up with the object that's in the path + # of the strategy object. however other options like + # with_loader_criteria() that doesn't have a path (has a fixed entity) + # and needs to have access to the latest closure state in order to + # be correct, we need to use the uncached one. + # + # as of #8399 we let the loader option itself figure out what it + # wants to do given cached and uncached version of itself. + + effective_path = path[self.parent_property] + + if orig_query is context.query: + new_options = orig_query._with_options + else: + cached_options = orig_query._with_options + uncached_options = context.query._with_options + + # propagate compile state options from the original query, + # updating their "extra_criteria" as necessary. + # note this will create a different cache key than + # "orig" options if extra_criteria is present, because the copy + # of extra_criteria will have different boundparam than that of + # the QueryableAttribute in the path + new_options = [ + orig_opt._adapt_cached_option_to_uncached_option( + context, uncached_opt + ) + for orig_opt, uncached_opt in zip( + cached_options, uncached_options + ) + ] + + if loadopt and loadopt._extra_criteria: + new_options += ( + orm_util.LoaderCriteriaOption( + effective_entity, + loadopt._generate_extra_criteria(context), + ), + ) + + if recursion_depth is not None: + effective_path = effective_path._truncate_recursive() + + q = q.options(*new_options) + + q = q._update_compile_options({"_current_path": effective_path}) + if context.populate_existing: + q = q.execution_options(populate_existing=True) + + if self.parent_property.order_by: + if not query_info.load_with_join: + eager_order_by = self.parent_property.order_by + if effective_entity.is_aliased_class: + eager_order_by = [ + effective_entity._adapt_element(elem) + for elem in eager_order_by + ] + q = q.order_by(*eager_order_by) + else: + + def _setup_outermost_orderby(compile_context): + compile_context.eager_order_by += tuple( + util.to_list(self.parent_property.order_by) + ) + + q = q._add_context_option( + _setup_outermost_orderby, self.parent_property + ) + + if query_info.load_only_child: + self._load_via_child( + our_states, + none_states, + query_info, + q, + context, + execution_options, + ) + else: + self._load_via_parent( + our_states, query_info, q, context, execution_options + ) + + def _load_via_child( + self, + our_states, + none_states, + query_info, + q, + context, + execution_options, + ): + uselist = self.uselist + + # this sort is really for the benefit of the unit tests + our_keys = sorted(our_states) + while our_keys: + chunk = our_keys[0 : self._chunksize] + our_keys = our_keys[self._chunksize :] + data = { + k: v + for k, v in context.session.execute( + q, + params={ + "primary_keys": [ + key[0] if query_info.zero_idx else key + for key in chunk + ] + }, + execution_options=execution_options, + ).unique() + } + + for key in chunk: + # for a real foreign key and no concurrent changes to the + # DB while running this method, "key" is always present in + # data. However, for primaryjoins without real foreign keys + # a non-None primaryjoin condition may still refer to no + # related object. + related_obj = data.get(key, None) + for state, dict_, overwrite in our_states[key]: + if not overwrite and self.key in dict_: + continue + + state.get_impl(self.key).set_committed_value( + state, + dict_, + related_obj if not uselist else [related_obj], + ) + # populate none states with empty value / collection + for state, dict_, overwrite in none_states: + if not overwrite and self.key in dict_: + continue + + # note it's OK if this is a uselist=True attribute, the empty + # collection will be populated + state.get_impl(self.key).set_committed_value(state, dict_, None) + + def _load_via_parent( + self, our_states, query_info, q, context, execution_options + ): + uselist = self.uselist + _empty_result = () if uselist else None + + while our_states: + chunk = our_states[0 : self._chunksize] + our_states = our_states[self._chunksize :] + + primary_keys = [ + key[0] if query_info.zero_idx else key + for key, state, state_dict, overwrite in chunk + ] + + data = collections.defaultdict(list) + for k, v in itertools.groupby( + context.session.execute( + q, + params={"primary_keys": primary_keys}, + execution_options=execution_options, + ).unique(), + lambda x: x[0], + ): + data[k].extend(vv[1] for vv in v) + + for key, state, state_dict, overwrite in chunk: + if not overwrite and self.key in state_dict: + continue + + collection = data.get(key, _empty_result) + + if not uselist and collection: + if len(collection) > 1: + util.warn( + "Multiple rows returned with " + "uselist=False for eagerly-loaded " + "attribute '%s' " % self + ) + state.get_impl(self.key).set_committed_value( + state, state_dict, collection[0] + ) + else: + # note that empty tuple set on uselist=False sets the + # value to None + state.get_impl(self.key).set_committed_value( + state, state_dict, collection + ) + + +def single_parent_validator(desc, prop): + def _do_check(state, value, oldvalue, initiator): + if value is not None and initiator.key == prop.key: + hasparent = initiator.hasparent(attributes.instance_state(value)) + if hasparent and oldvalue is not value: + raise sa_exc.InvalidRequestError( + "Instance %s is already associated with an instance " + "of %s via its %s attribute, and is only allowed a " + "single parent." + % (orm_util.instance_str(value), state.class_, prop), + code="bbf1", + ) + return value + + def append(state, value, initiator): + return _do_check(state, value, None, initiator) + + def set_(state, value, oldvalue, initiator): + return _do_check(state, value, oldvalue, initiator) + + event.listen( + desc, "append", append, raw=True, retval=True, active_history=True + ) + event.listen(desc, "set", set_, raw=True, retval=True, active_history=True) |