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evaluator.py
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# orm/evaluator.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 """Evaluation functions used **INTERNALLY** by ORM DML use cases. This module is **private, for internal use by SQLAlchemy**. .. versionchanged:: 2.0.4 renamed ``EvaluatorCompiler`` to ``_EvaluatorCompiler``. """ from __future__ import annotations from typing import Type from . import exc as orm_exc from .base import LoaderCallableStatus from .base import PassiveFlag from .. import exc from .. import inspect from ..sql import and_ from ..sql import operators from ..sql.sqltypes import Integer from ..sql.sqltypes import Numeric from ..util import warn_deprecated class UnevaluatableError(exc.InvalidRequestError): pass class _NoObject(operators.ColumnOperators): def operate(self, *arg, **kw): return None def reverse_operate(self, *arg, **kw): return None class _ExpiredObject(operators.ColumnOperators): def operate(self, *arg, **kw): return self def reverse_operate(self, *arg, **kw): return self _NO_OBJECT = _NoObject() _EXPIRED_OBJECT = _ExpiredObject() class _EvaluatorCompiler: def __init__(self, target_cls=None): self.target_cls = target_cls def process(self, clause, *clauses): if clauses: clause = and_(clause, *clauses) meth = getattr(self, f"visit_{clause.__visit_name__}", None) if not meth: raise UnevaluatableError( f"Cannot evaluate {type(clause).__name__}" ) return meth(clause) def visit_grouping(self, clause): return self.process(clause.element) def visit_null(self, clause): return lambda obj: None def visit_false(self, clause): return lambda obj: False def visit_true(self, clause): return lambda obj: True def visit_column(self, clause): try: parentmapper = clause._annotations["parentmapper"] except KeyError as ke: raise UnevaluatableError( f"Cannot evaluate column: {clause}" ) from ke if self.target_cls and not issubclass( self.target_cls, parentmapper.class_ ): raise UnevaluatableError( "Can't evaluate criteria against " f"alternate class {parentmapper.class_}" ) parentmapper._check_configure() # we'd like to use "proxy_key" annotation to get the "key", however # in relationship primaryjoin cases proxy_key is sometimes deannotated # and sometimes apparently not present in the first place (?). # While I can stop it from being deannotated (though need to see if # this breaks other things), not sure right now about cases where it's # not there in the first place. can fix at some later point. # key = clause._annotations["proxy_key"] # for now, use the old way try: key = parentmapper._columntoproperty[clause].key except orm_exc.UnmappedColumnError as err: raise UnevaluatableError( f"Cannot evaluate expression: {err}" ) from err # note this used to fall back to a simple `getattr(obj, key)` evaluator # if impl was None; as of #8656, we ensure mappers are configured # so that impl is available impl = parentmapper.class_manager[key].impl def get_corresponding_attr(obj): if obj is None: return _NO_OBJECT state = inspect(obj) dict_ = state.dict value = impl.get( state, dict_, passive=PassiveFlag.PASSIVE_NO_FETCH ) if value is LoaderCallableStatus.PASSIVE_NO_RESULT: return _EXPIRED_OBJECT return value return get_corresponding_attr def visit_tuple(self, clause): return self.visit_clauselist(clause) def visit_expression_clauselist(self, clause): return self.visit_clauselist(clause) def visit_clauselist(self, clause): evaluators = [self.process(clause) for clause in clause.clauses] dispatch = ( f"visit_{clause.operator.__name__.rstrip('_')}_clauselist_op" ) meth = getattr(self, dispatch, None) if meth: return meth(clause.operator, evaluators, clause) else: raise UnevaluatableError( f"Cannot evaluate clauselist with operator {clause.operator}" ) def visit_binary(self, clause): eval_left = self.process(clause.left) eval_right = self.process(clause.right) dispatch = f"visit_{clause.operator.__name__.rstrip('_')}_binary_op" meth = getattr(self, dispatch, None) if meth: return meth(clause.operator, eval_left, eval_right, clause) else: raise UnevaluatableError( f"Cannot evaluate {type(clause).__name__} with " f"operator {clause.operator}" ) def visit_or_clauselist_op(self, operator, evaluators, clause): def evaluate(obj): has_null = False for sub_evaluate in evaluators: value = sub_evaluate(obj) if value is _EXPIRED_OBJECT: return _EXPIRED_OBJECT elif value: return True has_null = has_null or value is None if has_null: return None return False return evaluate def visit_and_clauselist_op(self, operator, evaluators, clause): def evaluate(obj): for sub_evaluate in evaluators: value = sub_evaluate(obj) if value is _EXPIRED_OBJECT: return _EXPIRED_OBJECT if not value: if value is None or value is _NO_OBJECT: return None return False return True return evaluate def visit_comma_op_clauselist_op(self, operator, evaluators, clause): def evaluate(obj): values = [] for sub_evaluate in evaluators: value = sub_evaluate(obj) if value is _EXPIRED_OBJECT: return _EXPIRED_OBJECT elif value is None or value is _NO_OBJECT: return None values.append(value) return tuple(values) return evaluate def visit_custom_op_binary_op( self, operator, eval_left, eval_right, clause ): if operator.python_impl: return self._straight_evaluate( operator, eval_left, eval_right, clause ) else: raise UnevaluatableError( f"Custom operator {operator.opstring!r} can't be evaluated " "in Python unless it specifies a callable using " "`.python_impl`." ) def visit_is_binary_op(self, operator, eval_left, eval_right, clause): def evaluate(obj): left_val = eval_left(obj) right_val = eval_right(obj) if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT: return _EXPIRED_OBJECT return left_val == right_val return evaluate def visit_is_not_binary_op(self, operator, eval_left, eval_right, clause): def evaluate(obj): left_val = eval_left(obj) right_val = eval_right(obj) if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT: return _EXPIRED_OBJECT return left_val != right_val return evaluate def _straight_evaluate(self, operator, eval_left, eval_right, clause): def evaluate(obj): left_val = eval_left(obj) right_val = eval_right(obj) if left_val is _EXPIRED_OBJECT or right_val is _EXPIRED_OBJECT: return _EXPIRED_OBJECT elif left_val is None or right_val is None: return None return operator(eval_left(obj), eval_right(obj)) return evaluate def _straight_evaluate_numeric_only( self, operator, eval_left, eval_right, clause ): if clause.left.type._type_affinity not in ( Numeric, Integer, ) or clause.right.type._type_affinity not in (Numeric, Integer): raise UnevaluatableError( f'Cannot evaluate math operator "{operator.__name__}" for ' f"datatypes {clause.left.type}, {clause.right.type}" ) return self._straight_evaluate(operator, eval_left, eval_right, clause) visit_add_binary_op = _straight_evaluate_numeric_only visit_mul_binary_op = _straight_evaluate_numeric_only visit_sub_binary_op = _straight_evaluate_numeric_only visit_mod_binary_op = _straight_evaluate_numeric_only visit_truediv_binary_op = _straight_evaluate_numeric_only visit_lt_binary_op = _straight_evaluate visit_le_binary_op = _straight_evaluate visit_ne_binary_op = _straight_evaluate visit_gt_binary_op = _straight_evaluate visit_ge_binary_op = _straight_evaluate visit_eq_binary_op = _straight_evaluate def visit_in_op_binary_op(self, operator, eval_left, eval_right, clause): return self._straight_evaluate( lambda a, b: a in b if a is not _NO_OBJECT else None, eval_left, eval_right, clause, ) def visit_not_in_op_binary_op( self, operator, eval_left, eval_right, clause ): return self._straight_evaluate( lambda a, b: a not in b if a is not _NO_OBJECT else None, eval_left, eval_right, clause, ) def visit_concat_op_binary_op( self, operator, eval_left, eval_right, clause ): return self._straight_evaluate( lambda a, b: a + b, eval_left, eval_right, clause ) def visit_startswith_op_binary_op( self, operator, eval_left, eval_right, clause ): return self._straight_evaluate( lambda a, b: a.startswith(b), eval_left, eval_right, clause ) def visit_endswith_op_binary_op( self, operator, eval_left, eval_right, clause ): return self._straight_evaluate( lambda a, b: a.endswith(b), eval_left, eval_right, clause ) def visit_unary(self, clause): eval_inner = self.process(clause.element) if clause.operator is operators.inv: def evaluate(obj): value = eval_inner(obj) if value is _EXPIRED_OBJECT: return _EXPIRED_OBJECT elif value is None: return None return not value return evaluate raise UnevaluatableError( f"Cannot evaluate {type(clause).__name__} " f"with operator {clause.operator}" ) def visit_bindparam(self, clause): if clause.callable: val = clause.callable() else: val = clause.value return lambda obj: val def __getattr__(name: str) -> Type[_EvaluatorCompiler]: if name == "EvaluatorCompiler": warn_deprecated( "Direct use of 'EvaluatorCompiler' is not supported, and this " "name will be removed in a future release. " "'_EvaluatorCompiler' is for internal use only", "2.0", ) return _EvaluatorCompiler else: raise AttributeError(f"module {__name__!r} has no attribute {name!r}")