pep-484 for sqlalchemy.event; use future annotations

__future__.annotations mode allows us to use non-string
annotations for argument and return types in most cases,
but more importantly it removes a large amount of runtime
overhead that would be spent in evaluating the annotations.

Change-Id: I2f5b6126fe0019713fc50001be3627b664019ede
References: #6810

29 files changed, 58 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/_dml_constructors.py b/lib/sqlalchemy/sql/_dml_constructors.py
index e62edf5e6..a8c24413f 100644
--- a/lib/sqlalchemy/sql/_dml_constructors.py
+++ b/lib/sqlalchemy/sql/_dml_constructors.py
@@ -5,6 +5,8 @@
 # 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 .dml import Delete
 from .dml import Insert
 from .dml import Update
diff --git a/lib/sqlalchemy/sql/_elements_constructors.py b/lib/sqlalchemy/sql/_elements_constructors.py
index a8c9372e0..4132ac679 100644
--- a/lib/sqlalchemy/sql/_elements_constructors.py
+++ b/lib/sqlalchemy/sql/_elements_constructors.py
@@ -5,6 +5,8 @@
 # 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
+
 import typing
 from typing import Any
 from typing import cast as _typing_cast
diff --git a/lib/sqlalchemy/sql/_py_util.py b/lib/sqlalchemy/sql/_py_util.py
index 594967a40..96e8f6b2c 100644
--- a/lib/sqlalchemy/sql/_py_util.py
+++ b/lib/sqlalchemy/sql/_py_util.py
@@ -5,6 +5,8 @@
 # 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 typing import Dict
 
 
diff --git a/lib/sqlalchemy/sql/_selectable_constructors.py b/lib/sqlalchemy/sql/_selectable_constructors.py
index d3cf207da..9043aa6d0 100644
--- a/lib/sqlalchemy/sql/_selectable_constructors.py
+++ b/lib/sqlalchemy/sql/_selectable_constructors.py
@@ -5,6 +5,8 @@
 # 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 typing import Any
 from typing import Union
 
diff --git a/lib/sqlalchemy/sql/_typing.py b/lib/sqlalchemy/sql/_typing.py
index 4d2dd2688..7d8b9ee5c 100644
--- a/lib/sqlalchemy/sql/_typing.py
+++ b/lib/sqlalchemy/sql/_typing.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from typing import Any
 from typing import Mapping
 from typing import Sequence
diff --git a/lib/sqlalchemy/sql/annotation.py b/lib/sqlalchemy/sql/annotation.py
index c879bfc2d..b76393ad6 100644
--- a/lib/sqlalchemy/sql/annotation.py
+++ b/lib/sqlalchemy/sql/annotation.py
@@ -11,6 +11,8 @@ associations.
 
 """
 
+from __future__ import annotations
+
 from . import operators
 from .base import HasCacheKey
 from .traversals import anon_map
diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py
index 5828f9369..3936ed9c6 100644
--- a/lib/sqlalchemy/sql/base.py
+++ b/lib/sqlalchemy/sql/base.py
@@ -10,6 +10,8 @@
 """
 
 
+from __future__ import annotations
+
 import collections.abc as collections_abc
 from functools import reduce
 import itertools
diff --git a/lib/sqlalchemy/sql/cache_key.py b/lib/sqlalchemy/sql/cache_key.py
index 42bd60353..49f1899d5 100644
--- a/lib/sqlalchemy/sql/cache_key.py
+++ b/lib/sqlalchemy/sql/cache_key.py
@@ -5,6 +5,8 @@
 # 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 collections import namedtuple
 import enum
 from itertools import zip_longest
diff --git a/lib/sqlalchemy/sql/coercions.py b/lib/sqlalchemy/sql/coercions.py
index d5a75a165..d616417ab 100644
--- a/lib/sqlalchemy/sql/coercions.py
+++ b/lib/sqlalchemy/sql/coercions.py
@@ -5,6 +5,8 @@
 # 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
+
 import collections.abc as collections_abc
 import numbers
 import re
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index bf78b4231..4a169f719 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -22,6 +22,8 @@ To generate user-defined SQL strings, see
 :doc:`/ext/compiler`.
 
 """
+from __future__ import annotations
+
 import collections
 import collections.abc as collections_abc
 import contextlib
diff --git a/lib/sqlalchemy/sql/crud.py b/lib/sqlalchemy/sql/crud.py
index 4a0555bf4..4292aa916 100644
--- a/lib/sqlalchemy/sql/crud.py
+++ b/lib/sqlalchemy/sql/crud.py
@@ -9,6 +9,8 @@
 within INSERT and UPDATE statements.
 
 """
+from __future__ import annotations
+
 import functools
 import operator
 
diff --git a/lib/sqlalchemy/sql/ddl.py b/lib/sqlalchemy/sql/ddl.py
index f622023b0..7acb69beb 100644
--- a/lib/sqlalchemy/sql/ddl.py
+++ b/lib/sqlalchemy/sql/ddl.py
@@ -9,6 +9,8 @@ Provides the hierarchy of DDL-defining schema items as well as routines
 to invoke them for a create/drop call.
 
 """
+from __future__ import annotations
+
 import typing
 from typing import Callable
 from typing import List
diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py
index 1759e686e..001710d7b 100644
--- a/lib/sqlalchemy/sql/default_comparator.py
+++ b/lib/sqlalchemy/sql/default_comparator.py
@@ -8,6 +8,8 @@
 """Default implementation of SQL comparison operations.
 """
 
+from __future__ import annotations
+
 import typing
 from typing import Any
 from typing import Callable
diff --git a/lib/sqlalchemy/sql/dml.py b/lib/sqlalchemy/sql/dml.py
index 33dca66cd..5aded307b 100644
--- a/lib/sqlalchemy/sql/dml.py
+++ b/lib/sqlalchemy/sql/dml.py
@@ -9,6 +9,8 @@ Provide :class:`_expression.Insert`, :class:`_expression.Update` and
 :class:`_expression.Delete`.
 
 """
+from __future__ import annotations
+
 import collections.abc as collections_abc
 import typing
 
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index d14521ba7..0c532a135 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -10,6 +10,8 @@
 
 """
 
+from __future__ import annotations
+
 import itertools
 import operator
 import re
diff --git a/lib/sqlalchemy/sql/events.py b/lib/sqlalchemy/sql/events.py
index c42578986..1a1fc4c41 100644
--- a/lib/sqlalchemy/sql/events.py
+++ b/lib/sqlalchemy/sql/events.py
@@ -5,6 +5,8 @@
 # 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 .base import SchemaEventTarget
 from .. import event
 
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 22195cd7c..36ddbf309 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -11,6 +11,8 @@
 """
 
 
+from __future__ import annotations
+
 from ._dml_constructors import delete as delete
 from ._dml_constructors import insert as insert
 from ._dml_constructors import update as update
diff --git a/lib/sqlalchemy/sql/functions.py b/lib/sqlalchemy/sql/functions.py
index 2e6d64c55..eb3d17ee4 100644
--- a/lib/sqlalchemy/sql/functions.py
+++ b/lib/sqlalchemy/sql/functions.py
@@ -9,6 +9,8 @@
 
 """
 
+from __future__ import annotations
+
 from typing import Any
 from typing import TypeVar
 
diff --git a/lib/sqlalchemy/sql/lambdas.py b/lib/sqlalchemy/sql/lambdas.py
index ae7358870..9d011ef53 100644
--- a/lib/sqlalchemy/sql/lambdas.py
+++ b/lib/sqlalchemy/sql/lambdas.py
@@ -5,6 +5,8 @@
 # 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
+
 import collections.abc as collections_abc
 import inspect
 import itertools
diff --git a/lib/sqlalchemy/sql/naming.py b/lib/sqlalchemy/sql/naming.py
index 15a1566a6..9b6fcdbae 100644
--- a/lib/sqlalchemy/sql/naming.py
+++ b/lib/sqlalchemy/sql/naming.py
@@ -10,6 +10,8 @@
 
 """
 
+from __future__ import annotations
+
 import re
 
 from . import events  # noqa
diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index 255e77b7f..d4fa8042d 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -10,6 +10,8 @@
 
 """Defines operators used in SQL expressions."""
 
+from __future__ import annotations
+
 from operator import add as _uncast_add
 from operator import and_ as _uncast_and_
 from operator import contains as _uncast_contains
diff --git a/lib/sqlalchemy/sql/roles.py b/lib/sqlalchemy/sql/roles.py
index b41ef7a5d..64bd4b951 100644
--- a/lib/sqlalchemy/sql/roles.py
+++ b/lib/sqlalchemy/sql/roles.py
@@ -4,6 +4,8 @@
 #
 # 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
+
 import typing
 
 from sqlalchemy.util.langhelpers import TypingOnly
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index 9387ae030..528691795 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -28,6 +28,8 @@ Since these objects are part of the SQL expression language, they are usable
 as components in SQL expressions.
 
 """
+from __future__ import annotations
+
 import collections
 import typing
 from typing import Any
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index b0985f75d..7f6360edb 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -11,6 +11,8 @@ SQL tables and derived rowsets.
 
 """
 
+from __future__ import annotations
+
 import collections
 from enum import Enum
 import itertools
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index 0ec771cb4..819f1dc9a 100644
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -8,6 +8,8 @@
 """SQL specific types.
 
 """
+from __future__ import annotations
+
 import collections.abc as collections_abc
 import datetime as dt
 import decimal
diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py
index 18fd1d4b8..4fa23d370 100644
--- a/lib/sqlalchemy/sql/traversals.py
+++ b/lib/sqlalchemy/sql/traversals.py
@@ -5,6 +5,8 @@
 # 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 collections import deque
 import collections.abc as collections_abc
 import itertools
diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index 6b878dc70..f76b4e462 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -9,6 +9,8 @@
 
 """
 
+from __future__ import annotations
+
 import typing
 from typing import Any
 from typing import Callable
diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py
index c0de1902f..e3e358cdb 100644
--- a/lib/sqlalchemy/sql/util.py
+++ b/lib/sqlalchemy/sql/util.py
@@ -8,6 +8,8 @@
 """High level utilities which build upon other modules here.
 
 """
+from __future__ import annotations
+
 from collections import deque
 from itertools import chain
 import typing
diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py
index 640c07d61..523426d09 100644
--- a/lib/sqlalchemy/sql/visitors.py
+++ b/lib/sqlalchemy/sql/visitors.py
@@ -23,6 +23,8 @@ https://techspot.zzzeek.org/2008/01/23/expression-transformations/ .
 
 """
 
+from __future__ import annotations
+
 from collections import deque
 import itertools
 import operator