Update 2025-04-13_16:25:39

venv/lib/python3.11/site-packages/sqlalchemy/event/__init__.py

@@ -0,0 +1,25 @@
+# event/__init__.py
+# Copyright (C) 2005-2025 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
+
+from __future__ import annotations
+
+from .api import CANCEL as CANCEL
+from .api import contains as contains
+from .api import listen as listen
+from .api import listens_for as listens_for
+from .api import NO_RETVAL as NO_RETVAL
+from .api import remove as remove
+from .attr import _InstanceLevelDispatch as _InstanceLevelDispatch
+from .attr import RefCollection as RefCollection
+from .base import _Dispatch as _Dispatch
+from .base import _DispatchCommon as _DispatchCommon
+from .base import dispatcher as dispatcher
+from .base import Events as Events
+from .legacy import _legacy_signature as _legacy_signature
+from .registry import _EventKey as _EventKey
+from .registry import _ListenerFnType as _ListenerFnType
+from .registry import EventTarget as EventTarget

venv/lib/python3.11/site-packages/sqlalchemy/event/api.py

@@ -0,0 +1,222 @@
+# event/api.py
+# Copyright (C) 2005-2025 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
+
+"""Public API functions for the event system.
+
+"""
+from __future__ import annotations
+
+from typing import Any
+from typing import Callable
+
+from .base import _registrars
+from .registry import _ET
+from .registry import _EventKey
+from .registry import _ListenerFnType
+from .. import exc
+from .. import util
+
+
+CANCEL = util.symbol("CANCEL")
+NO_RETVAL = util.symbol("NO_RETVAL")
+
+
+def _event_key(
+    target: _ET, identifier: str, fn: _ListenerFnType
+) -> _EventKey[_ET]:
+    for evt_cls in _registrars[identifier]:
+        tgt = evt_cls._accept_with(target, identifier)
+        if tgt is not None:
+            return _EventKey(target, identifier, fn, tgt)
+    else:
+        raise exc.InvalidRequestError(
+            "No such event '%s' for target '%s'" % (identifier, target)
+        )
+
+
+def listen(
+    target: Any, identifier: str, fn: Callable[..., Any], *args: Any, **kw: Any
+) -> None:
+    """Register a listener function for the given target.
+
+    The :func:`.listen` function is part of the primary interface for the
+    SQLAlchemy event system, documented at :ref:`event_toplevel`.
+
+    e.g.::
+
+        from sqlalchemy import event
+        from sqlalchemy.schema import UniqueConstraint
+
+
+        def unique_constraint_name(const, table):
+            const.name = "uq_%s_%s" % (table.name, list(const.columns)[0].name)
+
+
+        event.listen(
+            UniqueConstraint, "after_parent_attach", unique_constraint_name
+        )
+
+    :param bool insert: The default behavior for event handlers is to append
+      the decorated user defined function to an internal list of registered
+      event listeners upon discovery. If a user registers a function with
+      ``insert=True``, SQLAlchemy will insert (prepend) the function to the
+      internal list upon discovery. This feature is not typically used or
+      recommended by the SQLAlchemy maintainers, but is provided to ensure
+      certain user defined functions can run before others, such as when
+      :ref:`Changing the sql_mode in MySQL <mysql_sql_mode>`.
+
+    :param bool named: When using named argument passing, the names listed in
+      the function argument specification will be used as keys in the
+      dictionary.
+      See :ref:`event_named_argument_styles`.
+
+    :param bool once: Private/Internal API usage. Deprecated.  This parameter
+      would provide that an event function would run only once per given
+      target. It does not however imply automatic de-registration of the
+      listener function; associating an arbitrarily high number of listeners
+      without explicitly removing them will cause memory to grow unbounded even
+      if ``once=True`` is specified.
+
+    :param bool propagate: The ``propagate`` kwarg is available when working
+      with ORM instrumentation and mapping events.
+      See :class:`_ormevent.MapperEvents` and
+      :meth:`_ormevent.MapperEvents.before_mapper_configured` for examples.
+
+    :param bool retval: This flag applies only to specific event listeners,
+      each of which includes documentation explaining when it should be used.
+      By default, no listener ever requires a return value.
+      However, some listeners do support special behaviors for return values,
+      and include in their documentation that the ``retval=True`` flag is
+      necessary for a return value to be processed.
+
+      Event listener suites that make use of :paramref:`_event.listen.retval`
+      include :class:`_events.ConnectionEvents` and
+      :class:`_ormevent.AttributeEvents`.
+
+    .. note::
+
+        The :func:`.listen` function cannot be called at the same time
+        that the target event is being run.   This has implications
+        for thread safety, and also means an event cannot be added
+        from inside the listener function for itself.  The list of
+        events to be run are present inside of a mutable collection
+        that can't be changed during iteration.
+
+        Event registration and removal is not intended to be a "high
+        velocity" operation; it is a configurational operation.  For
+        systems that need to quickly associate and deassociate with
+        events at high scale, use a mutable structure that is handled
+        from inside of a single listener.
+
+    .. seealso::
+
+        :func:`.listens_for`
+
+        :func:`.remove`
+
+    """
+
+    _event_key(target, identifier, fn).listen(*args, **kw)
+
+
+def listens_for(
+    target: Any, identifier: str, *args: Any, **kw: Any
+) -> Callable[[Callable[..., Any]], Callable[..., Any]]:
+    """Decorate a function as a listener for the given target + identifier.
+
+    The :func:`.listens_for` decorator is part of the primary interface for the
+    SQLAlchemy event system, documented at :ref:`event_toplevel`.
+
+    This function generally shares the same kwargs as :func:`.listen`.
+
+    e.g.::
+
+        from sqlalchemy import event
+        from sqlalchemy.schema import UniqueConstraint
+
+
+        @event.listens_for(UniqueConstraint, "after_parent_attach")
+        def unique_constraint_name(const, table):
+            const.name = "uq_%s_%s" % (table.name, list(const.columns)[0].name)
+
+    A given function can also be invoked for only the first invocation
+    of the event using the ``once`` argument::
+
+        @event.listens_for(Mapper, "before_configure", once=True)
+        def on_config():
+            do_config()
+
+    .. warning:: The ``once`` argument does not imply automatic de-registration
+       of the listener function after it has been invoked a first time; a
+       listener entry will remain associated with the target object.
+       Associating an arbitrarily high number of listeners without explicitly
+       removing them will cause memory to grow unbounded even if ``once=True``
+       is specified.
+
+    .. seealso::
+
+        :func:`.listen` - general description of event listening
+
+    """
+
+    def decorate(fn: Callable[..., Any]) -> Callable[..., Any]:
+        listen(target, identifier, fn, *args, **kw)
+        return fn
+
+    return decorate
+
+
+def remove(target: Any, identifier: str, fn: Callable[..., Any]) -> None:
+    """Remove an event listener.
+
+    The arguments here should match exactly those which were sent to
+    :func:`.listen`; all the event registration which proceeded as a result
+    of this call will be reverted by calling :func:`.remove` with the same
+    arguments.
+
+    e.g.::
+
+        # if a function was registered like this...
+        @event.listens_for(SomeMappedClass, "before_insert", propagate=True)
+        def my_listener_function(*arg):
+            pass
+
+
+        # ... it's removed like this
+        event.remove(SomeMappedClass, "before_insert", my_listener_function)
+
+    Above, the listener function associated with ``SomeMappedClass`` was also
+    propagated to subclasses of ``SomeMappedClass``; the :func:`.remove`
+    function will revert all of these operations.
+
+    .. note::
+
+        The :func:`.remove` function cannot be called at the same time
+        that the target event is being run.   This has implications
+        for thread safety, and also means an event cannot be removed
+        from inside the listener function for itself.  The list of
+        events to be run are present inside of a mutable collection
+        that can't be changed during iteration.
+
+        Event registration and removal is not intended to be a "high
+        velocity" operation; it is a configurational operation.  For
+        systems that need to quickly associate and deassociate with
+        events at high scale, use a mutable structure that is handled
+        from inside of a single listener.
+
+    .. seealso::
+
+        :func:`.listen`
+
+    """
+    _event_key(target, identifier, fn).remove()
+
+
+def contains(target: Any, identifier: str, fn: Callable[..., Any]) -> bool:
+    """Return True if the given target/ident/fn is set up to listen."""
+
+    return _event_key(target, identifier, fn).contains()

venv/lib/python3.11/site-packages/sqlalchemy/event/attr.py

@@ -0,0 +1,655 @@
+# event/attr.py
+# Copyright (C) 2005-2025 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
+
+"""Attribute implementation for _Dispatch classes.
+
+The various listener targets for a particular event class are represented
+as attributes, which refer to collections of listeners to be fired off.
+These collections can exist at the class level as well as at the instance
+level.  An event is fired off using code like this::
+
+    some_object.dispatch.first_connect(arg1, arg2)
+
+Above, ``some_object.dispatch`` would be an instance of ``_Dispatch`` and
+``first_connect`` is typically an instance of ``_ListenerCollection``
+if event listeners are present, or ``_EmptyListener`` if none are present.
+
+The attribute mechanics here spend effort trying to ensure listener functions
+are available with a minimum of function call overhead, that unnecessary
+objects aren't created (i.e. many empty per-instance listener collections),
+as well as that everything is garbage collectable when owning references are
+lost.  Other features such as "propagation" of listener functions across
+many ``_Dispatch`` instances, "joining" of multiple ``_Dispatch`` instances,
+as well as support for subclass propagation (e.g. events assigned to
+``Pool`` vs. ``QueuePool``) are all implemented here.
+
+"""
+from __future__ import annotations
+
+import collections
+from itertools import chain
+import threading
+from types import TracebackType
+import typing
+from typing import Any
+from typing import cast
+from typing import Collection
+from typing import Deque
+from typing import FrozenSet
+from typing import Generic
+from typing import Iterator
+from typing import MutableMapping
+from typing import MutableSequence
+from typing import NoReturn
+from typing import Optional
+from typing import Sequence
+from typing import Set
+from typing import Tuple
+from typing import Type
+from typing import TypeVar
+from typing import Union
+import weakref
+
+from . import legacy
+from . import registry
+from .registry import _ET
+from .registry import _EventKey
+from .registry import _ListenerFnType
+from .. import exc
+from .. import util
+from ..util.concurrency import AsyncAdaptedLock
+from ..util.typing import Protocol
+
+_T = TypeVar("_T", bound=Any)
+
+if typing.TYPE_CHECKING:
+    from .base import _Dispatch
+    from .base import _DispatchCommon
+    from .base import _HasEventsDispatch
+
+
+class RefCollection(util.MemoizedSlots, Generic[_ET]):
+    __slots__ = ("ref",)
+
+    ref: weakref.ref[RefCollection[_ET]]
+
+    def _memoized_attr_ref(self) -> weakref.ref[RefCollection[_ET]]:
+        return weakref.ref(self, registry._collection_gced)
+
+
+class _empty_collection(Collection[_T]):
+    def append(self, element: _T) -> None:
+        pass
+
+    def appendleft(self, element: _T) -> None:
+        pass
+
+    def extend(self, other: Sequence[_T]) -> None:
+        pass
+
+    def remove(self, element: _T) -> None:
+        pass
+
+    def __contains__(self, element: Any) -> bool:
+        return False
+
+    def __iter__(self) -> Iterator[_T]:
+        return iter([])
+
+    def clear(self) -> None:
+        pass
+
+    def __len__(self) -> int:
+        return 0
+
+
+_ListenerFnSequenceType = Union[Deque[_T], _empty_collection[_T]]
+
+
+class _ClsLevelDispatch(RefCollection[_ET]):
+    """Class-level events on :class:`._Dispatch` classes."""
+
+    __slots__ = (
+        "clsname",
+        "name",
+        "arg_names",
+        "has_kw",
+        "legacy_signatures",
+        "_clslevel",
+        "__weakref__",
+    )
+
+    clsname: str
+    name: str
+    arg_names: Sequence[str]
+    has_kw: bool
+    legacy_signatures: MutableSequence[legacy._LegacySignatureType]
+    _clslevel: MutableMapping[
+        Type[_ET], _ListenerFnSequenceType[_ListenerFnType]
+    ]
+
+    def __init__(
+        self,
+        parent_dispatch_cls: Type[_HasEventsDispatch[_ET]],
+        fn: _ListenerFnType,
+    ):
+        self.name = fn.__name__
+        self.clsname = parent_dispatch_cls.__name__
+        argspec = util.inspect_getfullargspec(fn)
+        self.arg_names = argspec.args[1:]
+        self.has_kw = bool(argspec.varkw)
+        self.legacy_signatures = list(
+            reversed(
+                sorted(
+                    getattr(fn, "_legacy_signatures", []), key=lambda s: s[0]
+                )
+            )
+        )
+        fn.__doc__ = legacy._augment_fn_docs(self, parent_dispatch_cls, fn)
+
+        self._clslevel = weakref.WeakKeyDictionary()
+
+    def _adjust_fn_spec(
+        self, fn: _ListenerFnType, named: bool
+    ) -> _ListenerFnType:
+        if named:
+            fn = self._wrap_fn_for_kw(fn)
+        if self.legacy_signatures:
+            try:
+                argspec = util.get_callable_argspec(fn, no_self=True)
+            except TypeError:
+                pass
+            else:
+                fn = legacy._wrap_fn_for_legacy(self, fn, argspec)
+        return fn
+
+    def _wrap_fn_for_kw(self, fn: _ListenerFnType) -> _ListenerFnType:
+        def wrap_kw(*args: Any, **kw: Any) -> Any:
+            argdict = dict(zip(self.arg_names, args))
+            argdict.update(kw)
+            return fn(**argdict)
+
+        return wrap_kw
+
+    def _do_insert_or_append(
+        self, event_key: _EventKey[_ET], is_append: bool
+    ) -> None:
+        target = event_key.dispatch_target
+        assert isinstance(
+            target, type
+        ), "Class-level Event targets must be classes."
+        if not getattr(target, "_sa_propagate_class_events", True):
+            raise exc.InvalidRequestError(
+                f"Can't assign an event directly to the {target} class"
+            )
+
+        cls: Type[_ET]
+
+        for cls in util.walk_subclasses(target):
+            if cls is not target and cls not in self._clslevel:
+                self.update_subclass(cls)
+            else:
+                if cls not in self._clslevel:
+                    self.update_subclass(cls)
+                if is_append:
+                    self._clslevel[cls].append(event_key._listen_fn)
+                else:
+                    self._clslevel[cls].appendleft(event_key._listen_fn)
+        registry._stored_in_collection(event_key, self)
+
+    def insert(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        self._do_insert_or_append(event_key, is_append=False)
+
+    def append(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        self._do_insert_or_append(event_key, is_append=True)
+
+    def update_subclass(self, target: Type[_ET]) -> None:
+        if target not in self._clslevel:
+            if getattr(target, "_sa_propagate_class_events", True):
+                self._clslevel[target] = collections.deque()
+            else:
+                self._clslevel[target] = _empty_collection()
+
+        clslevel = self._clslevel[target]
+        cls: Type[_ET]
+        for cls in target.__mro__[1:]:
+            if cls in self._clslevel:
+                clslevel.extend(
+                    [fn for fn in self._clslevel[cls] if fn not in clslevel]
+                )
+
+    def remove(self, event_key: _EventKey[_ET]) -> None:
+        target = event_key.dispatch_target
+        cls: Type[_ET]
+        for cls in util.walk_subclasses(target):
+            if cls in self._clslevel:
+                self._clslevel[cls].remove(event_key._listen_fn)
+        registry._removed_from_collection(event_key, self)
+
+    def clear(self) -> None:
+        """Clear all class level listeners"""
+
+        to_clear: Set[_ListenerFnType] = set()
+        for dispatcher in self._clslevel.values():
+            to_clear.update(dispatcher)
+            dispatcher.clear()
+        registry._clear(self, to_clear)
+
+    def for_modify(self, obj: _Dispatch[_ET]) -> _ClsLevelDispatch[_ET]:
+        """Return an event collection which can be modified.
+
+        For _ClsLevelDispatch at the class level of
+        a dispatcher, this returns self.
+
+        """
+        return self
+
+
+class _InstanceLevelDispatch(RefCollection[_ET], Collection[_ListenerFnType]):
+    __slots__ = ()
+
+    parent: _ClsLevelDispatch[_ET]
+
+    def _adjust_fn_spec(
+        self, fn: _ListenerFnType, named: bool
+    ) -> _ListenerFnType:
+        return self.parent._adjust_fn_spec(fn, named)
+
+    def __contains__(self, item: Any) -> bool:
+        raise NotImplementedError()
+
+    def __len__(self) -> int:
+        raise NotImplementedError()
+
+    def __iter__(self) -> Iterator[_ListenerFnType]:
+        raise NotImplementedError()
+
+    def __bool__(self) -> bool:
+        raise NotImplementedError()
+
+    def exec_once(self, *args: Any, **kw: Any) -> None:
+        raise NotImplementedError()
+
+    def exec_once_unless_exception(self, *args: Any, **kw: Any) -> None:
+        raise NotImplementedError()
+
+    def _exec_w_sync_on_first_run(self, *args: Any, **kw: Any) -> None:
+        raise NotImplementedError()
+
+    def __call__(self, *args: Any, **kw: Any) -> None:
+        raise NotImplementedError()
+
+    def insert(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        raise NotImplementedError()
+
+    def append(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        raise NotImplementedError()
+
+    def remove(self, event_key: _EventKey[_ET]) -> None:
+        raise NotImplementedError()
+
+    def for_modify(
+        self, obj: _DispatchCommon[_ET]
+    ) -> _InstanceLevelDispatch[_ET]:
+        """Return an event collection which can be modified.
+
+        For _ClsLevelDispatch at the class level of
+        a dispatcher, this returns self.
+
+        """
+        return self
+
+
+class _EmptyListener(_InstanceLevelDispatch[_ET]):
+    """Serves as a proxy interface to the events
+    served by a _ClsLevelDispatch, when there are no
+    instance-level events present.
+
+    Is replaced by _ListenerCollection when instance-level
+    events are added.
+
+    """
+
+    __slots__ = "parent", "parent_listeners", "name"
+
+    propagate: FrozenSet[_ListenerFnType] = frozenset()
+    listeners: Tuple[()] = ()
+    parent: _ClsLevelDispatch[_ET]
+    parent_listeners: _ListenerFnSequenceType[_ListenerFnType]
+    name: str
+
+    def __init__(self, parent: _ClsLevelDispatch[_ET], target_cls: Type[_ET]):
+        if target_cls not in parent._clslevel:
+            parent.update_subclass(target_cls)
+        self.parent = parent
+        self.parent_listeners = parent._clslevel[target_cls]
+        self.name = parent.name
+
+    def for_modify(
+        self, obj: _DispatchCommon[_ET]
+    ) -> _ListenerCollection[_ET]:
+        """Return an event collection which can be modified.
+
+        For _EmptyListener at the instance level of
+        a dispatcher, this generates a new
+        _ListenerCollection, applies it to the instance,
+        and returns it.
+
+        """
+        obj = cast("_Dispatch[_ET]", obj)
+
+        assert obj._instance_cls is not None
+        result = _ListenerCollection(self.parent, obj._instance_cls)
+        if getattr(obj, self.name) is self:
+            setattr(obj, self.name, result)
+        else:
+            assert isinstance(getattr(obj, self.name), _JoinedListener)
+        return result
+
+    def _needs_modify(self, *args: Any, **kw: Any) -> NoReturn:
+        raise NotImplementedError("need to call for_modify()")
+
+    def exec_once(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def exec_once_unless_exception(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def insert(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def append(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def remove(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def clear(self, *args: Any, **kw: Any) -> NoReturn:
+        self._needs_modify(*args, **kw)
+
+    def __call__(self, *args: Any, **kw: Any) -> None:
+        """Execute this event."""
+
+        for fn in self.parent_listeners:
+            fn(*args, **kw)
+
+    def __contains__(self, item: Any) -> bool:
+        return item in self.parent_listeners
+
+    def __len__(self) -> int:
+        return len(self.parent_listeners)
+
+    def __iter__(self) -> Iterator[_ListenerFnType]:
+        return iter(self.parent_listeners)
+
+    def __bool__(self) -> bool:
+        return bool(self.parent_listeners)
+
+
+class _MutexProtocol(Protocol):
+    def __enter__(self) -> bool: ...
+
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> Optional[bool]: ...
+
+
+class _CompoundListener(_InstanceLevelDispatch[_ET]):
+    __slots__ = (
+        "_exec_once_mutex",
+        "_exec_once",
+        "_exec_w_sync_once",
+        "_is_asyncio",
+    )
+
+    _exec_once_mutex: _MutexProtocol
+    parent_listeners: Collection[_ListenerFnType]
+    listeners: Collection[_ListenerFnType]
+    _exec_once: bool
+    _exec_w_sync_once: bool
+
+    def __init__(self, *arg: Any, **kw: Any):
+        super().__init__(*arg, **kw)
+        self._is_asyncio = False
+
+    def _set_asyncio(self) -> None:
+        self._is_asyncio = True
+
+    def _memoized_attr__exec_once_mutex(self) -> _MutexProtocol:
+        if self._is_asyncio:
+            return AsyncAdaptedLock()
+        else:
+            return threading.Lock()
+
+    def _exec_once_impl(
+        self, retry_on_exception: bool, *args: Any, **kw: Any
+    ) -> None:
+        with self._exec_once_mutex:
+            if not self._exec_once:
+                try:
+                    self(*args, **kw)
+                    exception = False
+                except:
+                    exception = True
+                    raise
+                finally:
+                    if not exception or not retry_on_exception:
+                        self._exec_once = True
+
+    def exec_once(self, *args: Any, **kw: Any) -> None:
+        """Execute this event, but only if it has not been
+        executed already for this collection."""
+
+        if not self._exec_once:
+            self._exec_once_impl(False, *args, **kw)
+
+    def exec_once_unless_exception(self, *args: Any, **kw: Any) -> None:
+        """Execute this event, but only if it has not been
+        executed already for this collection, or was called
+        by a previous exec_once_unless_exception call and
+        raised an exception.
+
+        If exec_once was already called, then this method will never run
+        the callable regardless of whether it raised or not.
+
+        .. versionadded:: 1.3.8
+
+        """
+        if not self._exec_once:
+            self._exec_once_impl(True, *args, **kw)
+
+    def _exec_w_sync_on_first_run(self, *args: Any, **kw: Any) -> None:
+        """Execute this event, and use a mutex if it has not been
+        executed already for this collection, or was called
+        by a previous _exec_w_sync_on_first_run call and
+        raised an exception.
+
+        If _exec_w_sync_on_first_run was already called and didn't raise an
+        exception, then a mutex is not used.
+
+        .. versionadded:: 1.4.11
+
+        """
+        if not self._exec_w_sync_once:
+            with self._exec_once_mutex:
+                try:
+                    self(*args, **kw)
+                except:
+                    raise
+                else:
+                    self._exec_w_sync_once = True
+        else:
+            self(*args, **kw)
+
+    def __call__(self, *args: Any, **kw: Any) -> None:
+        """Execute this event."""
+
+        for fn in self.parent_listeners:
+            fn(*args, **kw)
+        for fn in self.listeners:
+            fn(*args, **kw)
+
+    def __contains__(self, item: Any) -> bool:
+        return item in self.parent_listeners or item in self.listeners
+
+    def __len__(self) -> int:
+        return len(self.parent_listeners) + len(self.listeners)
+
+    def __iter__(self) -> Iterator[_ListenerFnType]:
+        return chain(self.parent_listeners, self.listeners)
+
+    def __bool__(self) -> bool:
+        return bool(self.listeners or self.parent_listeners)
+
+
+class _ListenerCollection(_CompoundListener[_ET]):
+    """Instance-level attributes on instances of :class:`._Dispatch`.
+
+    Represents a collection of listeners.
+
+    As of 0.7.9, _ListenerCollection is only first
+    created via the _EmptyListener.for_modify() method.
+
+    """
+
+    __slots__ = (
+        "parent_listeners",
+        "parent",
+        "name",
+        "listeners",
+        "propagate",
+        "__weakref__",
+    )
+
+    parent_listeners: Collection[_ListenerFnType]
+    parent: _ClsLevelDispatch[_ET]
+    name: str
+    listeners: Deque[_ListenerFnType]
+    propagate: Set[_ListenerFnType]
+
+    def __init__(self, parent: _ClsLevelDispatch[_ET], target_cls: Type[_ET]):
+        super().__init__()
+        if target_cls not in parent._clslevel:
+            parent.update_subclass(target_cls)
+        self._exec_once = False
+        self._exec_w_sync_once = False
+        self.parent_listeners = parent._clslevel[target_cls]
+        self.parent = parent
+        self.name = parent.name
+        self.listeners = collections.deque()
+        self.propagate = set()
+
+    def for_modify(
+        self, obj: _DispatchCommon[_ET]
+    ) -> _ListenerCollection[_ET]:
+        """Return an event collection which can be modified.
+
+        For _ListenerCollection at the instance level of
+        a dispatcher, this returns self.
+
+        """
+        return self
+
+    def _update(
+        self, other: _ListenerCollection[_ET], only_propagate: bool = True
+    ) -> None:
+        """Populate from the listeners in another :class:`_Dispatch`
+        object."""
+        existing_listeners = self.listeners
+        existing_listener_set = set(existing_listeners)
+        self.propagate.update(other.propagate)
+        other_listeners = [
+            l
+            for l in other.listeners
+            if l not in existing_listener_set
+            and not only_propagate
+            or l in self.propagate
+        ]
+
+        existing_listeners.extend(other_listeners)
+
+        if other._is_asyncio:
+            self._set_asyncio()
+
+        to_associate = other.propagate.union(other_listeners)
+        registry._stored_in_collection_multi(self, other, to_associate)
+
+    def insert(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        if event_key.prepend_to_list(self, self.listeners):
+            if propagate:
+                self.propagate.add(event_key._listen_fn)
+
+    def append(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        if event_key.append_to_list(self, self.listeners):
+            if propagate:
+                self.propagate.add(event_key._listen_fn)
+
+    def remove(self, event_key: _EventKey[_ET]) -> None:
+        self.listeners.remove(event_key._listen_fn)
+        self.propagate.discard(event_key._listen_fn)
+        registry._removed_from_collection(event_key, self)
+
+    def clear(self) -> None:
+        registry._clear(self, self.listeners)
+        self.propagate.clear()
+        self.listeners.clear()
+
+
+class _JoinedListener(_CompoundListener[_ET]):
+    __slots__ = "parent_dispatch", "name", "local", "parent_listeners"
+
+    parent_dispatch: _DispatchCommon[_ET]
+    name: str
+    local: _InstanceLevelDispatch[_ET]
+    parent_listeners: Collection[_ListenerFnType]
+
+    def __init__(
+        self,
+        parent_dispatch: _DispatchCommon[_ET],
+        name: str,
+        local: _EmptyListener[_ET],
+    ):
+        self._exec_once = False
+        self.parent_dispatch = parent_dispatch
+        self.name = name
+        self.local = local
+        self.parent_listeners = self.local
+
+    if not typing.TYPE_CHECKING:
+        # first error, I don't really understand:
+        # Signature of "listeners" incompatible with
+        # supertype "_CompoundListener"  [override]
+        # the name / return type are exactly the same
+        # second error is getattr_isn't typed, the cast() here
+        # adds too much method overhead
+        @property
+        def listeners(self) -> Collection[_ListenerFnType]:
+            return getattr(self.parent_dispatch, self.name)
+
+    def _adjust_fn_spec(
+        self, fn: _ListenerFnType, named: bool
+    ) -> _ListenerFnType:
+        return self.local._adjust_fn_spec(fn, named)
+
+    def for_modify(self, obj: _DispatchCommon[_ET]) -> _JoinedListener[_ET]:
+        self.local = self.parent_listeners = self.local.for_modify(obj)
+        return self
+
+    def insert(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        self.local.insert(event_key, propagate)
+
+    def append(self, event_key: _EventKey[_ET], propagate: bool) -> None:
+        self.local.append(event_key, propagate)
+
+    def remove(self, event_key: _EventKey[_ET]) -> None:
+        self.local.remove(event_key)
+
+    def clear(self) -> None:
+        raise NotImplementedError()

venv/lib/python3.11/site-packages/sqlalchemy/event/base.py

@@ -0,0 +1,472 @@
+# event/base.py
+# Copyright (C) 2005-2025 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
+
+"""Base implementation classes.
+
+The public-facing ``Events`` serves as the base class for an event interface;
+its public attributes represent different kinds of events.   These attributes
+are mirrored onto a ``_Dispatch`` class, which serves as a container for
+collections of listener functions.   These collections are represented both
+at the class level of a particular ``_Dispatch`` class as well as within
+instances of ``_Dispatch``.
+
+"""
+from __future__ import annotations
+
+import typing
+from typing import Any
+from typing import cast
+from typing import Dict
+from typing import Generic
+from typing import Iterator
+from typing import List
+from typing import Mapping
+from typing import MutableMapping
+from typing import Optional
+from typing import overload
+from typing import Tuple
+from typing import Type
+from typing import Union
+import weakref
+
+from .attr import _ClsLevelDispatch
+from .attr import _EmptyListener
+from .attr import _InstanceLevelDispatch
+from .attr import _JoinedListener
+from .registry import _ET
+from .registry import _EventKey
+from .. import util
+from ..util.typing import Literal
+
+_registrars: MutableMapping[str, List[Type[_HasEventsDispatch[Any]]]] = (
+    util.defaultdict(list)
+)
+
+
+def _is_event_name(name: str) -> bool:
+    # _sa_event prefix is special to support internal-only event names.
+    # most event names are just plain method names that aren't
+    # underscored.
+
+    return (
+        not name.startswith("_") and name != "dispatch"
+    ) or name.startswith("_sa_event")
+
+
+class _UnpickleDispatch:
+    """Serializable callable that re-generates an instance of
+    :class:`_Dispatch` given a particular :class:`.Events` subclass.
+
+    """
+
+    def __call__(self, _instance_cls: Type[_ET]) -> _Dispatch[_ET]:
+        for cls in _instance_cls.__mro__:
+            if "dispatch" in cls.__dict__:
+                return cast(
+                    "_Dispatch[_ET]", cls.__dict__["dispatch"].dispatch
+                )._for_class(_instance_cls)
+        else:
+            raise AttributeError("No class with a 'dispatch' member present.")
+
+
+class _DispatchCommon(Generic[_ET]):
+    __slots__ = ()
+
+    _instance_cls: Optional[Type[_ET]]
+
+    def _join(self, other: _DispatchCommon[_ET]) -> _JoinedDispatcher[_ET]:
+        raise NotImplementedError()
+
+    def __getattr__(self, name: str) -> _InstanceLevelDispatch[_ET]:
+        raise NotImplementedError()
+
+    @property
+    def _events(self) -> Type[_HasEventsDispatch[_ET]]:
+        raise NotImplementedError()
+
+
+class _Dispatch(_DispatchCommon[_ET]):
+    """Mirror the event listening definitions of an Events class with
+    listener collections.
+
+    Classes which define a "dispatch" member will return a
+    non-instantiated :class:`._Dispatch` subclass when the member
+    is accessed at the class level.  When the "dispatch" member is
+    accessed at the instance level of its owner, an instance
+    of the :class:`._Dispatch` class is returned.
+
+    A :class:`._Dispatch` class is generated for each :class:`.Events`
+    class defined, by the :meth:`._HasEventsDispatch._create_dispatcher_class`
+    method.  The original :class:`.Events` classes remain untouched.
+    This decouples the construction of :class:`.Events` subclasses from
+    the implementation used by the event internals, and allows
+    inspecting tools like Sphinx to work in an unsurprising
+    way against the public API.
+
+    """
+
+    # "active_history" is an ORM case we add here.   ideally a better
+    # system would be in place for ad-hoc attributes.
+    __slots__ = "_parent", "_instance_cls", "__dict__", "_empty_listeners"
+
+    _active_history: bool
+
+    _empty_listener_reg: MutableMapping[
+        Type[_ET], Dict[str, _EmptyListener[_ET]]
+    ] = weakref.WeakKeyDictionary()
+
+    _empty_listeners: Dict[str, _EmptyListener[_ET]]
+
+    _event_names: List[str]
+
+    _instance_cls: Optional[Type[_ET]]
+
+    _joined_dispatch_cls: Type[_JoinedDispatcher[_ET]]
+
+    _events: Type[_HasEventsDispatch[_ET]]
+    """reference back to the Events class.
+
+    Bidirectional against _HasEventsDispatch.dispatch
+
+    """
+
+    def __init__(
+        self,
+        parent: Optional[_Dispatch[_ET]],
+        instance_cls: Optional[Type[_ET]] = None,
+    ):
+        self._parent = parent
+        self._instance_cls = instance_cls
+
+        if instance_cls:
+            assert parent is not None
+            try:
+                self._empty_listeners = self._empty_listener_reg[instance_cls]
+            except KeyError:
+                self._empty_listeners = self._empty_listener_reg[
+                    instance_cls
+                ] = {
+                    ls.name: _EmptyListener(ls, instance_cls)
+                    for ls in parent._event_descriptors
+                }
+        else:
+            self._empty_listeners = {}
+
+    def __getattr__(self, name: str) -> _InstanceLevelDispatch[_ET]:
+        # Assign EmptyListeners as attributes on demand
+        # to reduce startup time for new dispatch objects.
+        try:
+            ls = self._empty_listeners[name]
+        except KeyError:
+            raise AttributeError(name)
+        else:
+            setattr(self, ls.name, ls)
+            return ls
+
+    @property
+    def _event_descriptors(self) -> Iterator[_ClsLevelDispatch[_ET]]:
+        for k in self._event_names:
+            # Yield _ClsLevelDispatch related
+            # to relevant event name.
+            yield getattr(self, k)
+
+    def _listen(self, event_key: _EventKey[_ET], **kw: Any) -> None:
+        return self._events._listen(event_key, **kw)
+
+    def _for_class(self, instance_cls: Type[_ET]) -> _Dispatch[_ET]:
+        return self.__class__(self, instance_cls)
+
+    def _for_instance(self, instance: _ET) -> _Dispatch[_ET]:
+        instance_cls = instance.__class__
+        return self._for_class(instance_cls)
+
+    def _join(self, other: _DispatchCommon[_ET]) -> _JoinedDispatcher[_ET]:
+        """Create a 'join' of this :class:`._Dispatch` and another.
+
+        This new dispatcher will dispatch events to both
+        :class:`._Dispatch` objects.
+
+        """
+        assert "_joined_dispatch_cls" in self.__class__.__dict__
+
+        return self._joined_dispatch_cls(self, other)
+
+    def __reduce__(self) -> Union[str, Tuple[Any, ...]]:
+        return _UnpickleDispatch(), (self._instance_cls,)
+
+    def _update(
+        self, other: _Dispatch[_ET], only_propagate: bool = True
+    ) -> None:
+        """Populate from the listeners in another :class:`_Dispatch`
+        object."""
+        for ls in other._event_descriptors:
+            if isinstance(ls, _EmptyListener):
+                continue
+            getattr(self, ls.name).for_modify(self)._update(
+                ls, only_propagate=only_propagate
+            )
+
+    def _clear(self) -> None:
+        for ls in self._event_descriptors:
+            ls.for_modify(self).clear()
+
+
+def _remove_dispatcher(cls: Type[_HasEventsDispatch[_ET]]) -> None:
+    for k in cls.dispatch._event_names:
+        _registrars[k].remove(cls)
+        if not _registrars[k]:
+            del _registrars[k]
+
+
+class _HasEventsDispatch(Generic[_ET]):
+    _dispatch_target: Optional[Type[_ET]]
+    """class which will receive the .dispatch collection"""
+
+    dispatch: _Dispatch[_ET]
+    """reference back to the _Dispatch class.
+
+    Bidirectional against _Dispatch._events
+
+    """
+
+    if typing.TYPE_CHECKING:
+
+        def __getattr__(self, name: str) -> _InstanceLevelDispatch[_ET]: ...
+
+    def __init_subclass__(cls) -> None:
+        """Intercept new Event subclasses and create associated _Dispatch
+        classes."""
+
+        cls._create_dispatcher_class(cls.__name__, cls.__bases__, cls.__dict__)
+
+    @classmethod
+    def _accept_with(
+        cls, target: Union[_ET, Type[_ET]], identifier: str
+    ) -> Optional[Union[_ET, Type[_ET]]]:
+        raise NotImplementedError()
+
+    @classmethod
+    def _listen(
+        cls,
+        event_key: _EventKey[_ET],
+        *,
+        propagate: bool = False,
+        insert: bool = False,
+        named: bool = False,
+        asyncio: bool = False,
+    ) -> None:
+        raise NotImplementedError()
+
+    @staticmethod
+    def _set_dispatch(
+        klass: Type[_HasEventsDispatch[_ET]],
+        dispatch_cls: Type[_Dispatch[_ET]],
+    ) -> _Dispatch[_ET]:
+        # This allows an Events subclass to define additional utility
+        # methods made available to the target via
+        # "self.dispatch._events.<utilitymethod>"
+        # @staticmethod to allow easy "super" calls while in a metaclass
+        # constructor.
+        klass.dispatch = dispatch_cls(None)
+        dispatch_cls._events = klass
+        return klass.dispatch
+
+    @classmethod
+    def _create_dispatcher_class(
+        cls, classname: str, bases: Tuple[type, ...], dict_: Mapping[str, Any]
+    ) -> None:
+        """Create a :class:`._Dispatch` class corresponding to an
+        :class:`.Events` class."""
+
+        # there's all kinds of ways to do this,
+        # i.e. make a Dispatch class that shares the '_listen' method
+        # of the Event class, this is the straight monkeypatch.
+        if hasattr(cls, "dispatch"):
+            dispatch_base = cls.dispatch.__class__
+        else:
+            dispatch_base = _Dispatch
+
+        event_names = [k for k in dict_ if _is_event_name(k)]
+        dispatch_cls = cast(
+            "Type[_Dispatch[_ET]]",
+            type(
+                "%sDispatch" % classname,
+                (dispatch_base,),
+                {"__slots__": event_names},
+            ),
+        )
+
+        dispatch_cls._event_names = event_names
+        dispatch_inst = cls._set_dispatch(cls, dispatch_cls)
+        for k in dispatch_cls._event_names:
+            setattr(dispatch_inst, k, _ClsLevelDispatch(cls, dict_[k]))
+            _registrars[k].append(cls)
+
+        for super_ in dispatch_cls.__bases__:
+            if issubclass(super_, _Dispatch) and super_ is not _Dispatch:
+                for ls in super_._events.dispatch._event_descriptors:
+                    setattr(dispatch_inst, ls.name, ls)
+                    dispatch_cls._event_names.append(ls.name)
+
+        if getattr(cls, "_dispatch_target", None):
+            dispatch_target_cls = cls._dispatch_target
+            assert dispatch_target_cls is not None
+            if (
+                hasattr(dispatch_target_cls, "__slots__")
+                and "_slots_dispatch" in dispatch_target_cls.__slots__
+            ):
+                dispatch_target_cls.dispatch = slots_dispatcher(cls)
+            else:
+                dispatch_target_cls.dispatch = dispatcher(cls)
+
+        klass = type(
+            "Joined%s" % dispatch_cls.__name__,
+            (_JoinedDispatcher,),
+            {"__slots__": event_names},
+        )
+        dispatch_cls._joined_dispatch_cls = klass
+
+        # establish pickle capability by adding it to this module
+        globals()[klass.__name__] = klass
+
+
+class _JoinedDispatcher(_DispatchCommon[_ET]):
+    """Represent a connection between two _Dispatch objects."""
+
+    __slots__ = "local", "parent", "_instance_cls"
+
+    local: _DispatchCommon[_ET]
+    parent: _DispatchCommon[_ET]
+    _instance_cls: Optional[Type[_ET]]
+
+    def __init__(
+        self, local: _DispatchCommon[_ET], parent: _DispatchCommon[_ET]
+    ):
+        self.local = local
+        self.parent = parent
+        self._instance_cls = self.local._instance_cls
+
+    def __reduce__(self) -> Any:
+        return (self.__class__, (self.local, self.parent))
+
+    def __getattr__(self, name: str) -> _JoinedListener[_ET]:
+        # Assign _JoinedListeners as attributes on demand
+        # to reduce startup time for new dispatch objects.
+        ls = getattr(self.local, name)
+        jl = _JoinedListener(self.parent, ls.name, ls)
+        setattr(self, ls.name, jl)
+        return jl
+
+    def _listen(self, event_key: _EventKey[_ET], **kw: Any) -> None:
+        return self.parent._listen(event_key, **kw)
+
+    @property
+    def _events(self) -> Type[_HasEventsDispatch[_ET]]:
+        return self.parent._events
+
+
+class Events(_HasEventsDispatch[_ET]):
+    """Define event listening functions for a particular target type."""
+
+    @classmethod
+    def _accept_with(
+        cls, target: Union[_ET, Type[_ET]], identifier: str
+    ) -> Optional[Union[_ET, Type[_ET]]]:
+        def dispatch_is(*types: Type[Any]) -> bool:
+            return all(isinstance(target.dispatch, t) for t in types)
+
+        def dispatch_parent_is(t: Type[Any]) -> bool:
+            parent = cast("_JoinedDispatcher[_ET]", target.dispatch).parent
+            while isinstance(parent, _JoinedDispatcher):
+                parent = cast("_JoinedDispatcher[_ET]", parent).parent
+
+            return isinstance(parent, t)
+
+        # Mapper, ClassManager, Session override this to
+        # also accept classes, scoped_sessions, sessionmakers, etc.
+        if hasattr(target, "dispatch"):
+            if (
+                dispatch_is(cls.dispatch.__class__)
+                or dispatch_is(type, cls.dispatch.__class__)
+                or (
+                    dispatch_is(_JoinedDispatcher)
+                    and dispatch_parent_is(cls.dispatch.__class__)
+                )
+            ):
+                return target
+
+        return None
+
+    @classmethod
+    def _listen(
+        cls,
+        event_key: _EventKey[_ET],
+        *,
+        propagate: bool = False,
+        insert: bool = False,
+        named: bool = False,
+        asyncio: bool = False,
+    ) -> None:
+        event_key.base_listen(
+            propagate=propagate, insert=insert, named=named, asyncio=asyncio
+        )
+
+    @classmethod
+    def _remove(cls, event_key: _EventKey[_ET]) -> None:
+        event_key.remove()
+
+    @classmethod
+    def _clear(cls) -> None:
+        cls.dispatch._clear()
+
+
+class dispatcher(Generic[_ET]):
+    """Descriptor used by target classes to
+    deliver the _Dispatch class at the class level
+    and produce new _Dispatch instances for target
+    instances.
+
+    """
+
+    def __init__(self, events: Type[_HasEventsDispatch[_ET]]):
+        self.dispatch = events.dispatch
+        self.events = events
+
+    @overload
+    def __get__(
+        self, obj: Literal[None], cls: Type[Any]
+    ) -> Type[_Dispatch[_ET]]: ...
+
+    @overload
+    def __get__(self, obj: Any, cls: Type[Any]) -> _DispatchCommon[_ET]: ...
+
+    def __get__(self, obj: Any, cls: Type[Any]) -> Any:
+        if obj is None:
+            return self.dispatch
+
+        disp = self.dispatch._for_instance(obj)
+        try:
+            obj.__dict__["dispatch"] = disp
+        except AttributeError as ae:
+            raise TypeError(
+                "target %r doesn't have __dict__, should it be "
+                "defining _slots_dispatch?" % (obj,)
+            ) from ae
+        return disp
+
+
+class slots_dispatcher(dispatcher[_ET]):
+    def __get__(self, obj: Any, cls: Type[Any]) -> Any:
+        if obj is None:
+            return self.dispatch
+
+        if hasattr(obj, "_slots_dispatch"):
+            return obj._slots_dispatch
+
+        disp = self.dispatch._for_instance(obj)
+        obj._slots_dispatch = disp
+        return disp

venv/lib/python3.11/site-packages/sqlalchemy/event/legacy.py

@@ -0,0 +1,246 @@
+# event/legacy.py
+# Copyright (C) 2005-2025 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
+
+"""Routines to handle adaption of legacy call signatures,
+generation of deprecation notes and docstrings.
+
+"""
+from __future__ import annotations
+
+import typing
+from typing import Any
+from typing import Callable
+from typing import List
+from typing import Optional
+from typing import Tuple
+from typing import Type
+
+from .registry import _ET
+from .registry import _ListenerFnType
+from .. import util
+from ..util.compat import FullArgSpec
+
+if typing.TYPE_CHECKING:
+    from .attr import _ClsLevelDispatch
+    from .base import _HasEventsDispatch
+
+
+_LegacySignatureType = Tuple[str, List[str], Optional[Callable[..., Any]]]
+
+
+def _legacy_signature(
+    since: str,
+    argnames: List[str],
+    converter: Optional[Callable[..., Any]] = None,
+) -> Callable[[Callable[..., Any]], Callable[..., Any]]:
+    """legacy sig decorator
+
+
+    :param since: string version for deprecation warning
+    :param argnames: list of strings, which is *all* arguments that the legacy
+     version accepted, including arguments that are still there
+    :param converter: lambda that will accept tuple of this full arg signature
+     and return tuple of new arg signature.
+
+    """
+
+    def leg(fn: Callable[..., Any]) -> Callable[..., Any]:
+        if not hasattr(fn, "_legacy_signatures"):
+            fn._legacy_signatures = []  # type: ignore[attr-defined]
+        fn._legacy_signatures.append((since, argnames, converter))  # type: ignore[attr-defined] # noqa: E501
+        return fn
+
+    return leg
+
+
+def _wrap_fn_for_legacy(
+    dispatch_collection: _ClsLevelDispatch[_ET],
+    fn: _ListenerFnType,
+    argspec: FullArgSpec,
+) -> _ListenerFnType:
+    for since, argnames, conv in dispatch_collection.legacy_signatures:
+        if argnames[-1] == "**kw":
+            has_kw = True
+            argnames = argnames[0:-1]
+        else:
+            has_kw = False
+
+        if len(argnames) == len(argspec.args) and has_kw is bool(
+            argspec.varkw
+        ):
+            formatted_def = "def %s(%s%s)" % (
+                dispatch_collection.name,
+                ", ".join(dispatch_collection.arg_names),
+                ", **kw" if has_kw else "",
+            )
+            warning_txt = (
+                'The argument signature for the "%s.%s" event listener '
+                "has changed as of version %s, and conversion for "
+                "the old argument signature will be removed in a "
+                'future release.  The new signature is "%s"'
+                % (
+                    dispatch_collection.clsname,
+                    dispatch_collection.name,
+                    since,
+                    formatted_def,
+                )
+            )
+
+            if conv is not None:
+                assert not has_kw
+
+                def wrap_leg(*args: Any, **kw: Any) -> Any:
+                    util.warn_deprecated(warning_txt, version=since)
+                    assert conv is not None
+                    return fn(*conv(*args))
+
+            else:
+
+                def wrap_leg(*args: Any, **kw: Any) -> Any:
+                    util.warn_deprecated(warning_txt, version=since)
+                    argdict = dict(zip(dispatch_collection.arg_names, args))
+                    args_from_dict = [argdict[name] for name in argnames]
+                    if has_kw:
+                        return fn(*args_from_dict, **kw)
+                    else:
+                        return fn(*args_from_dict)
+
+            return wrap_leg
+    else:
+        return fn
+
+
+def _indent(text: str, indent: str) -> str:
+    return "\n".join(indent + line for line in text.split("\n"))
+
+
+def _standard_listen_example(
+    dispatch_collection: _ClsLevelDispatch[_ET],
+    sample_target: Any,
+    fn: _ListenerFnType,
+) -> str:
+    example_kw_arg = _indent(
+        "\n".join(
+            "%(arg)s = kw['%(arg)s']" % {"arg": arg}
+            for arg in dispatch_collection.arg_names[0:2]
+        ),
+        "    ",
+    )
+    if dispatch_collection.legacy_signatures:
+        current_since = max(
+            since
+            for since, args, conv in dispatch_collection.legacy_signatures
+        )
+    else:
+        current_since = None
+    text = (
+        "from sqlalchemy import event\n\n\n"
+        "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+        "def receive_%(event_name)s("
+        "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+        "    \"listen for the '%(event_name)s' event\"\n"
+        "\n    # ... (event handling logic) ...\n"
+    )
+
+    text %= {
+        "current_since": (
+            " (arguments as of %s)" % current_since if current_since else ""
+        ),
+        "event_name": fn.__name__,
+        "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        "named_event_arguments": ", ".join(dispatch_collection.arg_names),
+        "example_kw_arg": example_kw_arg,
+        "sample_target": sample_target,
+    }
+    return text
+
+
+def _legacy_listen_examples(
+    dispatch_collection: _ClsLevelDispatch[_ET],
+    sample_target: str,
+    fn: _ListenerFnType,
+) -> str:
+    text = ""
+    for since, args, conv in dispatch_collection.legacy_signatures:
+        text += (
+            "\n# DEPRECATED calling style (pre-%(since)s, "
+            "will be removed in a future release)\n"
+            "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+            "def receive_%(event_name)s("
+            "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+            "    \"listen for the '%(event_name)s' event\"\n"
+            "\n    # ... (event handling logic) ...\n"
+            % {
+                "since": since,
+                "event_name": fn.__name__,
+                "has_kw_arguments": (
+                    " **kw" if dispatch_collection.has_kw else ""
+                ),
+                "named_event_arguments": ", ".join(args),
+                "sample_target": sample_target,
+            }
+        )
+    return text
+
+
+def _version_signature_changes(
+    parent_dispatch_cls: Type[_HasEventsDispatch[_ET]],
+    dispatch_collection: _ClsLevelDispatch[_ET],
+) -> str:
+    since, args, conv = dispatch_collection.legacy_signatures[0]
+    return (
+        "\n.. versionchanged:: %(since)s\n"
+        "    The :meth:`.%(clsname)s.%(event_name)s` event now accepts the \n"
+        "    arguments %(named_event_arguments)s%(has_kw_arguments)s.\n"
+        "    Support for listener functions which accept the previous \n"
+        '    argument signature(s) listed above as "deprecated" will be \n'
+        "    removed in a future release."
+        % {
+            "since": since,
+            "clsname": parent_dispatch_cls.__name__,
+            "event_name": dispatch_collection.name,
+            "named_event_arguments": ", ".join(
+                ":paramref:`.%(clsname)s.%(event_name)s.%(param_name)s`"
+                % {
+                    "clsname": parent_dispatch_cls.__name__,
+                    "event_name": dispatch_collection.name,
+                    "param_name": param_name,
+                }
+                for param_name in dispatch_collection.arg_names
+            ),
+            "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        }
+    )
+
+
+def _augment_fn_docs(
+    dispatch_collection: _ClsLevelDispatch[_ET],
+    parent_dispatch_cls: Type[_HasEventsDispatch[_ET]],
+    fn: _ListenerFnType,
+) -> str:
+    header = (
+        ".. container:: event_signatures\n\n"
+        "     Example argument forms::\n"
+        "\n"
+    )
+
+    sample_target = getattr(parent_dispatch_cls, "_target_class_doc", "obj")
+    text = header + _indent(
+        _standard_listen_example(dispatch_collection, sample_target, fn),
+        " " * 8,
+    )
+    if dispatch_collection.legacy_signatures:
+        text += _indent(
+            _legacy_listen_examples(dispatch_collection, sample_target, fn),
+            " " * 8,
+        )
+
+        text += _version_signature_changes(
+            parent_dispatch_cls, dispatch_collection
+        )
+
+    return util.inject_docstring_text(fn.__doc__, text, 1)

venv/lib/python3.11/site-packages/sqlalchemy/event/registry.py

@@ -0,0 +1,390 @@
+# event/registry.py
+# Copyright (C) 2005-2025 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
+
+"""Provides managed registration services on behalf of :func:`.listen`
+arguments.
+
+By "managed registration", we mean that event listening functions and
+other objects can be added to various collections in such a way that their
+membership in all those collections can be revoked at once, based on
+an equivalent :class:`._EventKey`.
+
+"""
+from __future__ import annotations
+
+import collections
+import types
+import typing
+from typing import Any
+from typing import Callable
+from typing import cast
+from typing import Deque
+from typing import Dict
+from typing import Generic
+from typing import Iterable
+from typing import Optional
+from typing import Tuple
+from typing import TypeVar
+from typing import Union
+import weakref
+
+from .. import exc
+from .. import util
+
+if typing.TYPE_CHECKING:
+    from .attr import RefCollection
+    from .base import dispatcher
+
+_ListenerFnType = Callable[..., Any]
+_ListenerFnKeyType = Union[int, Tuple[int, int]]
+_EventKeyTupleType = Tuple[int, str, _ListenerFnKeyType]
+
+
+_ET = TypeVar("_ET", bound="EventTarget")
+
+
+class EventTarget:
+    """represents an event target, that is, something we can listen on
+    either with that target as a class or as an instance.
+
+    Examples include:  Connection, Mapper, Table, Session,
+    InstrumentedAttribute, Engine, Pool, Dialect.
+
+    """
+
+    __slots__ = ()
+
+    dispatch: dispatcher[Any]
+
+
+_RefCollectionToListenerType = Dict[
+    "weakref.ref[RefCollection[Any]]",
+    "weakref.ref[_ListenerFnType]",
+]
+
+_key_to_collection: Dict[_EventKeyTupleType, _RefCollectionToListenerType] = (
+    collections.defaultdict(dict)
+)
+"""
+Given an original listen() argument, can locate all
+listener collections and the listener fn contained
+
+(target, identifier, fn) -> {
+                            ref(listenercollection) -> ref(listener_fn)
+                            ref(listenercollection) -> ref(listener_fn)
+                            ref(listenercollection) -> ref(listener_fn)
+                        }
+"""
+
+_ListenerToEventKeyType = Dict[
+    "weakref.ref[_ListenerFnType]",
+    _EventKeyTupleType,
+]
+_collection_to_key: Dict[
+    weakref.ref[RefCollection[Any]],
+    _ListenerToEventKeyType,
+] = collections.defaultdict(dict)
+"""
+Given a _ListenerCollection or _ClsLevelListener, can locate
+all the original listen() arguments and the listener fn contained
+
+ref(listenercollection) -> {
+                            ref(listener_fn) -> (target, identifier, fn),
+                            ref(listener_fn) -> (target, identifier, fn),
+                            ref(listener_fn) -> (target, identifier, fn),
+                        }
+"""
+
+
+def _collection_gced(ref: weakref.ref[Any]) -> None:
+    # defaultdict, so can't get a KeyError
+    if not _collection_to_key or ref not in _collection_to_key:
+        return
+
+    ref = cast("weakref.ref[RefCollection[EventTarget]]", ref)
+
+    listener_to_key = _collection_to_key.pop(ref)
+    for key in listener_to_key.values():
+        if key in _key_to_collection:
+            # defaultdict, so can't get a KeyError
+            dispatch_reg = _key_to_collection[key]
+            dispatch_reg.pop(ref)
+            if not dispatch_reg:
+                _key_to_collection.pop(key)
+
+
+def _stored_in_collection(
+    event_key: _EventKey[_ET], owner: RefCollection[_ET]
+) -> bool:
+    key = event_key._key
+
+    dispatch_reg = _key_to_collection[key]
+
+    owner_ref = owner.ref
+    listen_ref = weakref.ref(event_key._listen_fn)
+
+    if owner_ref in dispatch_reg:
+        return False
+
+    dispatch_reg[owner_ref] = listen_ref
+
+    listener_to_key = _collection_to_key[owner_ref]
+    listener_to_key[listen_ref] = key
+
+    return True
+
+
+def _removed_from_collection(
+    event_key: _EventKey[_ET], owner: RefCollection[_ET]
+) -> None:
+    key = event_key._key
+
+    dispatch_reg = _key_to_collection[key]
+
+    listen_ref = weakref.ref(event_key._listen_fn)
+
+    owner_ref = owner.ref
+    dispatch_reg.pop(owner_ref, None)
+    if not dispatch_reg:
+        del _key_to_collection[key]
+
+    if owner_ref in _collection_to_key:
+        listener_to_key = _collection_to_key[owner_ref]
+        # see #12216 - this guards against a removal that already occurred
+        # here. however, I cannot come up with a test that shows any negative
+        # side effects occurring from this removal happening, even though an
+        # event key may still be referenced from a clsleveldispatch here
+        listener_to_key.pop(listen_ref, None)
+
+
+def _stored_in_collection_multi(
+    newowner: RefCollection[_ET],
+    oldowner: RefCollection[_ET],
+    elements: Iterable[_ListenerFnType],
+) -> None:
+    if not elements:
+        return
+
+    oldowner_ref = oldowner.ref
+    newowner_ref = newowner.ref
+
+    old_listener_to_key = _collection_to_key[oldowner_ref]
+    new_listener_to_key = _collection_to_key[newowner_ref]
+
+    for listen_fn in elements:
+        listen_ref = weakref.ref(listen_fn)
+        try:
+            key = old_listener_to_key[listen_ref]
+        except KeyError:
+            # can occur during interpreter shutdown.
+            # see #6740
+            continue
+
+        try:
+            dispatch_reg = _key_to_collection[key]
+        except KeyError:
+            continue
+
+        if newowner_ref in dispatch_reg:
+            assert dispatch_reg[newowner_ref] == listen_ref
+        else:
+            dispatch_reg[newowner_ref] = listen_ref
+
+        new_listener_to_key[listen_ref] = key
+
+
+def _clear(
+    owner: RefCollection[_ET],
+    elements: Iterable[_ListenerFnType],
+) -> None:
+    if not elements:
+        return
+
+    owner_ref = owner.ref
+    listener_to_key = _collection_to_key[owner_ref]
+    for listen_fn in elements:
+        listen_ref = weakref.ref(listen_fn)
+        key = listener_to_key[listen_ref]
+        dispatch_reg = _key_to_collection[key]
+        dispatch_reg.pop(owner_ref, None)
+
+        if not dispatch_reg:
+            del _key_to_collection[key]
+
+
+class _EventKey(Generic[_ET]):
+    """Represent :func:`.listen` arguments."""
+
+    __slots__ = (
+        "target",
+        "identifier",
+        "fn",
+        "fn_key",
+        "fn_wrap",
+        "dispatch_target",
+    )
+
+    target: _ET
+    identifier: str
+    fn: _ListenerFnType
+    fn_key: _ListenerFnKeyType
+    dispatch_target: Any
+    _fn_wrap: Optional[_ListenerFnType]
+
+    def __init__(
+        self,
+        target: _ET,
+        identifier: str,
+        fn: _ListenerFnType,
+        dispatch_target: Any,
+        _fn_wrap: Optional[_ListenerFnType] = None,
+    ):
+        self.target = target
+        self.identifier = identifier
+        self.fn = fn
+        if isinstance(fn, types.MethodType):
+            self.fn_key = id(fn.__func__), id(fn.__self__)
+        else:
+            self.fn_key = id(fn)
+        self.fn_wrap = _fn_wrap
+        self.dispatch_target = dispatch_target
+
+    @property
+    def _key(self) -> _EventKeyTupleType:
+        return (id(self.target), self.identifier, self.fn_key)
+
+    def with_wrapper(self, fn_wrap: _ListenerFnType) -> _EventKey[_ET]:
+        if fn_wrap is self._listen_fn:
+            return self
+        else:
+            return _EventKey(
+                self.target,
+                self.identifier,
+                self.fn,
+                self.dispatch_target,
+                _fn_wrap=fn_wrap,
+            )
+
+    def with_dispatch_target(self, dispatch_target: Any) -> _EventKey[_ET]:
+        if dispatch_target is self.dispatch_target:
+            return self
+        else:
+            return _EventKey(
+                self.target,
+                self.identifier,
+                self.fn,
+                dispatch_target,
+                _fn_wrap=self.fn_wrap,
+            )
+
+    def listen(self, *args: Any, **kw: Any) -> None:
+        once = kw.pop("once", False)
+        once_unless_exception = kw.pop("_once_unless_exception", False)
+        named = kw.pop("named", False)
+
+        target, identifier, fn = (
+            self.dispatch_target,
+            self.identifier,
+            self._listen_fn,
+        )
+
+        dispatch_collection = getattr(target.dispatch, identifier)
+
+        adjusted_fn = dispatch_collection._adjust_fn_spec(fn, named)
+
+        self = self.with_wrapper(adjusted_fn)
+
+        stub_function = getattr(
+            self.dispatch_target.dispatch._events, self.identifier
+        )
+        if hasattr(stub_function, "_sa_warn"):
+            stub_function._sa_warn()
+
+        if once or once_unless_exception:
+            self.with_wrapper(
+                util.only_once(
+                    self._listen_fn, retry_on_exception=once_unless_exception
+                )
+            ).listen(*args, **kw)
+        else:
+            self.dispatch_target.dispatch._listen(self, *args, **kw)
+
+    def remove(self) -> None:
+        key = self._key
+
+        if key not in _key_to_collection:
+            raise exc.InvalidRequestError(
+                "No listeners found for event %s / %r / %s "
+                % (self.target, self.identifier, self.fn)
+            )
+
+        dispatch_reg = _key_to_collection.pop(key)
+
+        for collection_ref, listener_ref in dispatch_reg.items():
+            collection = collection_ref()
+            listener_fn = listener_ref()
+            if collection is not None and listener_fn is not None:
+                collection.remove(self.with_wrapper(listener_fn))
+
+    def contains(self) -> bool:
+        """Return True if this event key is registered to listen."""
+        return self._key in _key_to_collection
+
+    def base_listen(
+        self,
+        propagate: bool = False,
+        insert: bool = False,
+        named: bool = False,
+        retval: Optional[bool] = None,
+        asyncio: bool = False,
+    ) -> None:
+        target, identifier = self.dispatch_target, self.identifier
+
+        dispatch_collection = getattr(target.dispatch, identifier)
+
+        for_modify = dispatch_collection.for_modify(target.dispatch)
+        if asyncio:
+            for_modify._set_asyncio()
+
+        if insert:
+            for_modify.insert(self, propagate)
+        else:
+            for_modify.append(self, propagate)
+
+    @property
+    def _listen_fn(self) -> _ListenerFnType:
+        return self.fn_wrap or self.fn
+
+    def append_to_list(
+        self,
+        owner: RefCollection[_ET],
+        list_: Deque[_ListenerFnType],
+    ) -> bool:
+        if _stored_in_collection(self, owner):
+            list_.append(self._listen_fn)
+            return True
+        else:
+            return False
+
+    def remove_from_list(
+        self,
+        owner: RefCollection[_ET],
+        list_: Deque[_ListenerFnType],
+    ) -> None:
+        _removed_from_collection(self, owner)
+        list_.remove(self._listen_fn)
+
+    def prepend_to_list(
+        self,
+        owner: RefCollection[_ET],
+        list_: Deque[_ListenerFnType],
+    ) -> bool:
+        if _stored_in_collection(self, owner):
+            list_.appendleft(self._listen_fn)
+            return True
+        else:
+            return False