Remove 3.6 support

Author: SimonCW

pyproject.toml

@@ -49,8 +49,6 @@ fastapi = "^0.68.1"
 requests = "^2.26.0"
 autoflake = "^1.4"
 isort = "^5.9.3"
-async_generator = {version = "*", python = "~3.6"}
-async-exit-stack = {version = "*", python = "~3.6"}
 
 [build-system]
 requires = ["poetry-core"]

sqlmodel/sql/expression.py.jinja2

@@ -22,37 +22,15 @@ from sqlalchemy.sql.expression import Select as _Select
 
 _TSelect = TypeVar("_TSelect")
 
-# Workaround Generics incompatibility in Python 3.6
-# Ref: https://github.com/python/typing/issues/449#issuecomment-316061322
-if sys.version_info.minor >= 7:
-
-    class Select(_Select, Generic[_TSelect]):
-        inherit_cache = True
-
-    # This is not comparable to sqlalchemy.sql.selectable.ScalarSelect, that has a different
-    # purpose. This is the same as a normal SQLAlchemy Select class where there's only one
-    # entity, so the result will be converted to a scalar by default. This way writing
-    # for loops on the results will feel natural.
-    class SelectOfScalar(_Select, Generic[_TSelect]):
-        inherit_cache = True
-
-else:
-    from typing import GenericMeta  # type: ignore
-
-    class GenericSelectMeta(GenericMeta, _Select.__class__):  # type: ignore
-        pass
-
-    class _Py36Select(_Select, Generic[_TSelect], metaclass=GenericSelectMeta):
-        inherit_cache = True
-
-    class _Py36SelectOfScalar(_Select, Generic[_TSelect], metaclass=GenericSelectMeta):
-        inherit_cache = True
-
-    # Cast them for editors to work correctly, from several tricks tried, this works
-    # for both VS Code and PyCharm
-    Select = cast("Select", _Py36Select)  # type: ignore
-    SelectOfScalar = cast("SelectOfScalar", _Py36SelectOfScalar)  # type: ignore
-
+class Select(_Select, Generic[_TSelect]):
+    inherit_cache = True
+
+# This is not comparable to sqlalchemy.sql.selectable.ScalarSelect, that has a different
+# purpose. This is the same as a normal SQLAlchemy Select class where there's only one
+# entity, so the result will be converted to a scalar by default. This way writing
+# for loops on the results will feel natural.
+class SelectOfScalar(_Select, Generic[_TSelect]):
+    inherit_cache = True
 
 if TYPE_CHECKING:  # pragma: no cover
     from ..main import SQLModel