propose new pep-484 no-pluguns declarative layer

References: https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/3074

Fixes: #170

sqlalchemy-stubs/orm/__init__.pyi

@@ -3,6 +3,7 @@ from typing import Mapping
 from typing import Optional
 from typing import Tuple
 
+from . import decl_m as m  # noqa
 from . import exc as exc
 from . import mapper as mapperlib  # noqa
 from . import strategy_options

sqlalchemy-stubs/orm/decl_m.pyi

@@ -0,0 +1,170 @@
+from typing import AbstractSet
+from typing import Any
+from typing import Callable
+from typing import Literal
+from typing import Mapping
+from typing import MutableMapping
+from typing import Optional
+from typing import overload
+from typing import Sequence
+from typing import Tuple
+from typing import Type
+from typing import TypeVar
+from typing import Union
+
+from sqlalchemy.sql.elements import ColumnElement
+from .attributes import Mapped as Mapped
+from .relationships import _OrderByArgument
+from ..sql import schema
+from ..sql import sqltypes
+from ..sql.schema import _ServerDefaultType
+from ..sql.schema import FetchedValue
+from ..sql.schema import SchemaEventTarget
+
+_T = TypeVar("_T")
+
+_BackrefResult = Tuple[str, Mapping[str, Any]]
+
+class MappedColumn(Mapped[_T]):
+    def __init__(self, expr: _T) -> None: ...
+    def operate(self, op: Any, *other: Any, **kwargs: Any): ...
+    def reverse_operate(self, op: Any, other: Any, **kwargs: Any): ...
+
+@overload
+def column(
+    __name: str,
+    *args: SchemaEventTarget,
+    autoincrement: Union[bool, Literal["auto", "ignore_fk"]] = ...,
+    default: Optional[Any] = ...,
+    doc: Optional[str] = ...,
+    key: Optional[str] = ...,
+    index: Optional[bool] = ...,
+    info: MutableMapping[Any, Any] = ...,
+    nullable: bool = ...,
+    onupdate: Optional[Any] = ...,
+    primary_key: bool = ...,
+    server_default: Optional[_ServerDefaultType[Any]] = ...,
+    server_onupdate: Optional[FetchedValue] = ...,
+    quote: Optional[bool] = ...,
+    unique: Optional[bool] = ...,
+    system: bool = ...,
+    comment: Optional[str] = ...,
+    **kwargs: Any,
+) -> Mapped[Any]: ...
+@overload
+def column(
+    *args: SchemaEventTarget,
+    autoincrement: Union[bool, Literal["auto", "ignore_fk"]] = ...,
+    default: Optional[Any] = ...,
+    doc: Optional[str] = ...,
+    key: Optional[str] = ...,
+    index: Optional[bool] = ...,
+    info: MutableMapping[Any, Any] = ...,
+    nullable: bool = ...,
+    onupdate: Optional[Any] = ...,
+    primary_key: bool = ...,
+    server_default: Optional[_ServerDefaultType[Any]] = ...,
+    server_onupdate: Optional[FetchedValue] = ...,
+    quote: Optional[bool] = ...,
+    unique: Optional[bool] = ...,
+    system: bool = ...,
+    comment: Optional[str] = ...,
+    **kwargs: Any,
+) -> Mapped[Any]: ...
+@overload
+def column(
+    __name: str,
+    _type: Union[sqltypes.TypeEngine[_T], Type[sqltypes.TypeEngine[_T]]],
+    *args: SchemaEventTarget,
+    autoincrement: Union[bool, Literal["auto", "ignore_fk"]] = ...,
+    default: Optional[Any] = ...,
+    doc: Optional[str] = ...,
+    key: Optional[str] = ...,
+    index: Optional[bool] = ...,
+    info: MutableMapping[Any, Any] = ...,
+    nullable: bool = ...,
+    onupdate: Optional[Any] = ...,
+    primary_key: bool = ...,
+    server_default: Optional[_ServerDefaultType[schema._TE]] = ...,
+    server_onupdate: Optional[FetchedValue] = ...,
+    quote: Optional[bool] = ...,
+    unique: Optional[bool] = ...,
+    system: bool = ...,
+    comment: Optional[str] = ...,
+    **kwargs: Any,
+) -> Mapped[_T]: ...
+@overload
+def column(
+    _type: Union[sqltypes.TypeEngine[_T], Type[sqltypes.TypeEngine[_T]]],
+    *args: SchemaEventTarget,
+    autoincrement: Union[bool, Literal["auto", "ignore_fk"]] = ...,
+    default: Optional[Any] = ...,
+    doc: Optional[str] = ...,
+    key: Optional[str] = ...,
+    index: Optional[bool] = ...,
+    info: MutableMapping[Any, Any] = ...,
+    nullable: bool = ...,
+    onupdate: Optional[Any] = ...,
+    primary_key: bool = ...,
+    server_default: Optional[_ServerDefaultType[schema._TE]] = ...,
+    server_onupdate: Optional[FetchedValue] = ...,
+    quote: Optional[bool] = ...,
+    unique: Optional[bool] = ...,
+    system: bool = ...,
+    comment: Optional[str] = ...,
+    **kwargs: Any,
+) -> Mapped[_T]: ...
+def column_property(
+    expr: ColumnElement[sqltypes.TypeEngine[_T]],
+    *addl: ColumnElement[Any],
+    **kw: Any,
+) -> Mapped[_T]: ...
+def composite(cls: _T, *arg: Any, **kw: Any) -> Mapped[_T]: ...
+def deferred(
+    expr: ColumnElement[sqltypes.TypeEngine[_T]],
+    *addl: ColumnElement[Any],
+    **kw: Any,
+) -> Mapped[_T]: ...
+def query_expression(
+    typ: sqltypes.TypeEngine[_T], default_expr: Any = ...
+) -> Mapped[_T]: ...
+def synonym(*arg, **kw) -> Any: ...
+def related(
+    entity: Optional[_T] = ...,
+    secondary: Optional[Any] = ...,
+    primaryjoin: Optional[Any] = ...,
+    secondaryjoin: Optional[Any] = ...,
+    foreign_keys: Optional[Any] = ...,
+    uselist: Optional[bool] = ...,
+    order_by: _OrderByArgument = ...,
+    backref: Union[str, _BackrefResult] = ...,
+    back_populates: str = ...,
+    overlaps: Union[AbstractSet[str], str] = ...,
+    post_update: bool = ...,
+    cascade: Union[Literal[False], Sequence[str]] = ...,
+    viewonly: bool = ...,
+    lazy: str = ...,
+    collection_class: Optional[Union[Type[Any], Callable[[], Any]]] = ...,
+    passive_deletes: Union[bool, Literal["all"]] = ...,
+    passive_updates: bool = ...,
+    remote_side: Optional[Any] = ...,
+    enable_typechecks: bool = ...,  # NOTE: not documented
+    join_depth: Optional[int] = ...,
+    comparator_factory: Optional[Any] = ...,
+    single_parent: bool = ...,
+    innerjoin: Union[bool, str] = ...,
+    distinct_target_key: Optional[bool] = ...,
+    doc: Optional[str] = ...,
+    active_history: bool = ...,
+    cascade_backrefs: bool = ...,
+    load_on_pending: bool = ...,
+    bake_queries: bool = ...,
+    _local_remote_pairs: Optional[Any] = ...,
+    query_class: Optional[Any] = ...,
+    info: Optional[MutableMapping[Any, Any]] = ...,
+    omit_join: Optional[Literal[False]] = ...,
+    sync_backref: Optional[Any] = ...,
+) -> Mapped[_T]: ...
+def declared_attr(
+    fget: Callable[[Any], Mapped[_T]], cascading: bool = ...
+) -> Mapped[_T]: ...