487 lines
16 KiB
Python
487 lines
16 KiB
Python
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# ext/mypy/decl_class.py
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# Copyright (C) 2021 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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from typing import Optional
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from typing import Union
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from mypy import nodes
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from mypy.nodes import AssignmentStmt
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from mypy.nodes import CallExpr
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from mypy.nodes import ClassDef
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from mypy.nodes import Decorator
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from mypy.nodes import ListExpr
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from mypy.nodes import MemberExpr
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from mypy.nodes import NameExpr
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from mypy.nodes import PlaceholderNode
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from mypy.nodes import RefExpr
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from mypy.nodes import StrExpr
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from mypy.nodes import SymbolNode
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from mypy.nodes import SymbolTableNode
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from mypy.nodes import TempNode
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from mypy.nodes import TypeInfo
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from mypy.nodes import Var
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from mypy.plugin import SemanticAnalyzerPluginInterface
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from mypy.types import AnyType
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from mypy.types import CallableType
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from mypy.types import get_proper_type
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from mypy.types import Instance
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from mypy.types import NoneType
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from mypy.types import ProperType
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from mypy.types import Type
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from mypy.types import TypeOfAny
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from mypy.types import UnboundType
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from mypy.types import UnionType
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from . import apply
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from . import infer
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from . import names
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from . import util
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def _scan_declarative_assignments_and_apply_types(
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cls: ClassDef,
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api: SemanticAnalyzerPluginInterface,
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is_mixin_scan: bool = False,
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) -> Optional[util.DeclClassApplied]:
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info = util._info_for_cls(cls, api)
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if info is None:
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# this can occur during cached passes
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return None
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elif cls.fullname.startswith("builtins"):
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return None
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elif "_sa_decl_class_applied" in info.metadata:
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cls_metadata = util.DeclClassApplied.deserialize(
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info.metadata["_sa_decl_class_applied"], api
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)
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# ensure that a class that's mapped is always picked up by
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# its mapped() decorator or declarative metaclass before
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# it would be detected as an unmapped mixin class
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if not is_mixin_scan:
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assert cls_metadata.is_mapped
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# mypy can call us more than once. it then *may* have reset the
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# left hand side of everything, but not the right that we removed,
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# removing our ability to re-scan. but we have the types
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# here, so lets re-apply them, or if we have an UnboundType,
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# we can re-scan
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apply._re_apply_declarative_assignments(cls, api, cls_metadata)
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return cls_metadata
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cls_metadata = util.DeclClassApplied(not is_mixin_scan, False, [], [])
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if not cls.defs.body:
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# when we get a mixin class from another file, the body is
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# empty (!) but the names are in the symbol table. so use that.
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for sym_name, sym in info.names.items():
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_scan_symbol_table_entry(cls, api, sym_name, sym, cls_metadata)
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else:
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for stmt in util._flatten_typechecking(cls.defs.body):
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if isinstance(stmt, AssignmentStmt):
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_scan_declarative_assignment_stmt(cls, api, stmt, cls_metadata)
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elif isinstance(stmt, Decorator):
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_scan_declarative_decorator_stmt(cls, api, stmt, cls_metadata)
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_scan_for_mapped_bases(cls, api, cls_metadata)
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if not is_mixin_scan:
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apply._add_additional_orm_attributes(cls, api, cls_metadata)
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info.metadata["_sa_decl_class_applied"] = cls_metadata.serialize()
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return cls_metadata
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def _scan_symbol_table_entry(
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cls: ClassDef,
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api: SemanticAnalyzerPluginInterface,
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name: str,
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value: SymbolTableNode,
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cls_metadata: util.DeclClassApplied,
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) -> None:
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"""Extract mapping information from a SymbolTableNode that's in the
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type.names dictionary.
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"""
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value_type = get_proper_type(value.type)
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if not isinstance(value_type, Instance):
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return
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left_hand_explicit_type = None
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type_id = names._type_id_for_named_node(value_type.type)
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# type_id = names._type_id_for_unbound_type(value.type.type, cls, api)
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err = False
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# TODO: this is nearly the same logic as that of
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# _scan_declarative_decorator_stmt, likely can be merged
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if type_id in {
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names.MAPPED,
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names.RELATIONSHIP,
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names.COMPOSITE_PROPERTY,
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names.MAPPER_PROPERTY,
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names.SYNONYM_PROPERTY,
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names.COLUMN_PROPERTY,
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}:
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if value_type.args:
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left_hand_explicit_type = get_proper_type(value_type.args[0])
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else:
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err = True
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elif type_id is names.COLUMN:
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if not value_type.args:
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err = True
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else:
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typeengine_arg: Union[ProperType, TypeInfo] = get_proper_type(
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value_type.args[0]
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)
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if isinstance(typeengine_arg, Instance):
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typeengine_arg = typeengine_arg.type
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if isinstance(typeengine_arg, (UnboundType, TypeInfo)):
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sym = api.lookup_qualified(typeengine_arg.name, typeengine_arg)
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if sym is not None and isinstance(sym.node, TypeInfo):
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if names._has_base_type_id(sym.node, names.TYPEENGINE):
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left_hand_explicit_type = UnionType(
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[
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infer._extract_python_type_from_typeengine(
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api, sym.node, []
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),
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NoneType(),
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]
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)
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else:
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util.fail(
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api,
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"Column type should be a TypeEngine "
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"subclass not '{}'".format(sym.node.fullname),
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value_type,
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)
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if err:
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msg = (
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"Can't infer type from attribute {} on class {}. "
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"please specify a return type from this function that is "
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"one of: Mapped[<python type>], relationship[<target class>], "
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"Column[<TypeEngine>], MapperProperty[<python type>]"
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)
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util.fail(api, msg.format(name, cls.name), cls)
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left_hand_explicit_type = AnyType(TypeOfAny.special_form)
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if left_hand_explicit_type is not None:
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cls_metadata.mapped_attr_names.append((name, left_hand_explicit_type))
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def _scan_declarative_decorator_stmt(
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cls: ClassDef,
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api: SemanticAnalyzerPluginInterface,
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stmt: Decorator,
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cls_metadata: util.DeclClassApplied,
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) -> None:
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"""Extract mapping information from a @declared_attr in a declarative
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class.
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E.g.::
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@reg.mapped
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class MyClass:
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# ...
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@declared_attr
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def updated_at(cls) -> Column[DateTime]:
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return Column(DateTime)
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Will resolve in mypy as::
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@reg.mapped
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class MyClass:
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# ...
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updated_at: Mapped[Optional[datetime.datetime]]
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"""
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for dec in stmt.decorators:
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if (
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isinstance(dec, (NameExpr, MemberExpr, SymbolNode))
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and names._type_id_for_named_node(dec) is names.DECLARED_ATTR
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):
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break
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else:
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return
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dec_index = cls.defs.body.index(stmt)
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left_hand_explicit_type: Optional[ProperType] = None
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if isinstance(stmt.func.type, CallableType):
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func_type = stmt.func.type.ret_type
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if isinstance(func_type, UnboundType):
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type_id = names._type_id_for_unbound_type(func_type, cls, api)
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else:
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# this does not seem to occur unless the type argument is
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# incorrect
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return
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if (
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type_id
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in {
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names.MAPPED,
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names.RELATIONSHIP,
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names.COMPOSITE_PROPERTY,
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names.MAPPER_PROPERTY,
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names.SYNONYM_PROPERTY,
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names.COLUMN_PROPERTY,
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}
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and func_type.args
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):
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left_hand_explicit_type = get_proper_type(func_type.args[0])
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elif type_id is names.COLUMN and func_type.args:
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typeengine_arg = func_type.args[0]
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if isinstance(typeengine_arg, UnboundType):
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sym = api.lookup_qualified(typeengine_arg.name, typeengine_arg)
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if sym is not None and isinstance(sym.node, TypeInfo):
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if names._has_base_type_id(sym.node, names.TYPEENGINE):
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left_hand_explicit_type = UnionType(
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[
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infer._extract_python_type_from_typeengine(
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api, sym.node, []
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),
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NoneType(),
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]
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)
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else:
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util.fail(
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api,
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"Column type should be a TypeEngine "
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"subclass not '{}'".format(sym.node.fullname),
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func_type,
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)
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if left_hand_explicit_type is None:
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# no type on the decorated function. our option here is to
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# dig into the function body and get the return type, but they
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# should just have an annotation.
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msg = (
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"Can't infer type from @declared_attr on function '{}'; "
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"please specify a return type from this function that is "
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"one of: Mapped[<python type>], relationship[<target class>], "
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"Column[<TypeEngine>], MapperProperty[<python type>]"
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)
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util.fail(api, msg.format(stmt.var.name), stmt)
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left_hand_explicit_type = AnyType(TypeOfAny.special_form)
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left_node = NameExpr(stmt.var.name)
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left_node.node = stmt.var
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# totally feeling around in the dark here as I don't totally understand
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# the significance of UnboundType. It seems to be something that is
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# not going to do what's expected when it is applied as the type of
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# an AssignmentStatement. So do a feeling-around-in-the-dark version
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# of converting it to the regular Instance/TypeInfo/UnionType structures
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# we see everywhere else.
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if isinstance(left_hand_explicit_type, UnboundType):
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left_hand_explicit_type = get_proper_type(
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util._unbound_to_instance(api, left_hand_explicit_type)
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)
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left_node.node.type = api.named_type(
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"__sa_Mapped", [left_hand_explicit_type]
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)
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# this will ignore the rvalue entirely
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# rvalue = TempNode(AnyType(TypeOfAny.special_form))
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# rewrite the node as:
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# <attr> : Mapped[<typ>] =
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# _sa_Mapped._empty_constructor(lambda: <function body>)
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# the function body is maintained so it gets type checked internally
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column_descriptor = nodes.NameExpr("__sa_Mapped")
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column_descriptor.fullname = "sqlalchemy.orm.attributes.Mapped"
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mm = nodes.MemberExpr(column_descriptor, "_empty_constructor")
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arg = nodes.LambdaExpr(stmt.func.arguments, stmt.func.body)
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rvalue = CallExpr(
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mm,
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[arg],
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[nodes.ARG_POS],
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["arg1"],
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)
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new_stmt = AssignmentStmt([left_node], rvalue)
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new_stmt.type = left_node.node.type
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cls_metadata.mapped_attr_names.append(
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(left_node.name, left_hand_explicit_type)
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)
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cls.defs.body[dec_index] = new_stmt
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def _scan_declarative_assignment_stmt(
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cls: ClassDef,
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api: SemanticAnalyzerPluginInterface,
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stmt: AssignmentStmt,
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cls_metadata: util.DeclClassApplied,
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) -> None:
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"""Extract mapping information from an assignment statement in a
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declarative class.
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"""
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lvalue = stmt.lvalues[0]
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if not isinstance(lvalue, NameExpr):
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return
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sym = cls.info.names.get(lvalue.name)
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# this establishes that semantic analysis has taken place, which
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# means the nodes are populated and we are called from an appropriate
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# hook.
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assert sym is not None
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node = sym.node
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if isinstance(node, PlaceholderNode):
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return
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assert node is lvalue.node
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assert isinstance(node, Var)
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if node.name == "__abstract__":
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if api.parse_bool(stmt.rvalue) is True:
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cls_metadata.is_mapped = False
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return
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elif node.name == "__tablename__":
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cls_metadata.has_table = True
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elif node.name.startswith("__"):
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return
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elif node.name == "_mypy_mapped_attrs":
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if not isinstance(stmt.rvalue, ListExpr):
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util.fail(api, "_mypy_mapped_attrs is expected to be a list", stmt)
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else:
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for item in stmt.rvalue.items:
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if isinstance(item, (NameExpr, StrExpr)):
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apply._apply_mypy_mapped_attr(cls, api, item, cls_metadata)
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left_hand_mapped_type: Optional[Type] = None
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left_hand_explicit_type: Optional[ProperType] = None
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||
|
|
if node.is_inferred or node.type is None:
|
||
|
|
if isinstance(stmt.type, UnboundType):
|
||
|
|
# look for an explicit Mapped[] type annotation on the left
|
||
|
|
# side with nothing on the right
|
||
|
|
|
||
|
|
# print(stmt.type)
|
||
|
|
# Mapped?[Optional?[A?]]
|
||
|
|
|
||
|
|
left_hand_explicit_type = stmt.type
|
||
|
|
|
||
|
|
if stmt.type.name == "Mapped":
|
||
|
|
mapped_sym = api.lookup_qualified("Mapped", cls)
|
||
|
|
if (
|
||
|
|
mapped_sym is not None
|
||
|
|
and mapped_sym.node is not None
|
||
|
|
and names._type_id_for_named_node(mapped_sym.node)
|
||
|
|
is names.MAPPED
|
||
|
|
):
|
||
|
|
left_hand_explicit_type = get_proper_type(
|
||
|
|
stmt.type.args[0]
|
||
|
|
)
|
||
|
|
left_hand_mapped_type = stmt.type
|
||
|
|
|
||
|
|
# TODO: do we need to convert from unbound for this case?
|
||
|
|
# left_hand_explicit_type = util._unbound_to_instance(
|
||
|
|
# api, left_hand_explicit_type
|
||
|
|
# )
|
||
|
|
else:
|
||
|
|
node_type = get_proper_type(node.type)
|
||
|
|
if (
|
||
|
|
isinstance(node_type, Instance)
|
||
|
|
and names._type_id_for_named_node(node_type.type) is names.MAPPED
|
||
|
|
):
|
||
|
|
# print(node.type)
|
||
|
|
# sqlalchemy.orm.attributes.Mapped[<python type>]
|
||
|
|
left_hand_explicit_type = get_proper_type(node_type.args[0])
|
||
|
|
left_hand_mapped_type = node_type
|
||
|
|
else:
|
||
|
|
# print(node.type)
|
||
|
|
# <python type>
|
||
|
|
left_hand_explicit_type = node_type
|
||
|
|
left_hand_mapped_type = None
|
||
|
|
|
||
|
|
if isinstance(stmt.rvalue, TempNode) and left_hand_mapped_type is not None:
|
||
|
|
# annotation without assignment and Mapped is present
|
||
|
|
# as type annotation
|
||
|
|
# equivalent to using _infer_type_from_left_hand_type_only.
|
||
|
|
|
||
|
|
python_type_for_type = left_hand_explicit_type
|
||
|
|
elif isinstance(stmt.rvalue, CallExpr) and isinstance(
|
||
|
|
stmt.rvalue.callee, RefExpr
|
||
|
|
):
|
||
|
|
|
||
|
|
python_type_for_type = infer._infer_type_from_right_hand_nameexpr(
|
||
|
|
api, stmt, node, left_hand_explicit_type, stmt.rvalue.callee
|
||
|
|
)
|
||
|
|
|
||
|
|
if python_type_for_type is None:
|
||
|
|
return
|
||
|
|
|
||
|
|
else:
|
||
|
|
return
|
||
|
|
|
||
|
|
assert python_type_for_type is not None
|
||
|
|
|
||
|
|
cls_metadata.mapped_attr_names.append((node.name, python_type_for_type))
|
||
|
|
|
||
|
|
apply._apply_type_to_mapped_statement(
|
||
|
|
api,
|
||
|
|
stmt,
|
||
|
|
lvalue,
|
||
|
|
left_hand_explicit_type,
|
||
|
|
python_type_for_type,
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
def _scan_for_mapped_bases(
|
||
|
|
cls: ClassDef,
|
||
|
|
api: SemanticAnalyzerPluginInterface,
|
||
|
|
cls_metadata: util.DeclClassApplied,
|
||
|
|
) -> None:
|
||
|
|
"""Given a class, iterate through its superclass hierarchy to find
|
||
|
|
all other classes that are considered as ORM-significant.
|
||
|
|
|
||
|
|
Locates non-mapped mixins and scans them for mapped attributes to be
|
||
|
|
applied to subclasses.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
info = util._info_for_cls(cls, api)
|
||
|
|
|
||
|
|
baseclasses = list(info.bases)
|
||
|
|
|
||
|
|
while baseclasses:
|
||
|
|
base: Instance = baseclasses.pop(0)
|
||
|
|
|
||
|
|
if base.type.fullname.startswith("builtins"):
|
||
|
|
continue
|
||
|
|
|
||
|
|
# scan each base for mapped attributes. if they are not already
|
||
|
|
# scanned (but have all their type info), that means they are unmapped
|
||
|
|
# mixins
|
||
|
|
base_decl_class_applied = (
|
||
|
|
_scan_declarative_assignments_and_apply_types(
|
||
|
|
base.type.defn, api, is_mixin_scan=True
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
if base_decl_class_applied is not None:
|
||
|
|
cls_metadata.mapped_mro.append(base)
|
||
|
|
baseclasses.extend(base.type.bases)
|