establish mypy / typing approach for v2.0

large patch to get ORM / typing efforts started.
this is to support adding new test cases to mypy,
support dropping sqlalchemy2-stubs entirely from the
test suite, validate major ORM typing reorganization
to eliminate the need for the mypy plugin.

* New declarative approach which uses annotation
  introspection, fixes: #7535
* Mapped[] is now at the base of all ORM constructs
  that find themselves in classes, to support direct
  typing without plugins
* Mypy plugin updated for new typing structures
* Mypy test suite broken out into "plugin" tests vs.
  "plain" tests, and enhanced to better support test
  structures where we assert that various objects are
  introspected by the type checker as we expect.
  as we go forward with typing, we will
  add new use cases to "plain" where we can assert that
  types are introspected as we expect.
* For typing support, users will be much more exposed to the
  class names of things.  Add these all to "sqlalchemy" import
  space.
* Column(ForeignKey()) no longer needs to be `@declared_attr`
  if the FK refers to a remote table
* composite() attributes mapped to a dataclass no longer
  need to implement a `__composite_values__()` method
* with_variant() accepts multiple dialect names

Change-Id: I22797c0be73a8fbbd2d6f5e0c0b7258b17fe145d
Fixes: #7535
Fixes: #7551
References: #6810

1 files changed, 14 insertions, 33 deletions

diff --git a/lib/sqlalchemy/pool/__init__.py b/lib/sqlalchemy/pool/__init__.py
index 38059856e..bc2f93d57 100644
--- a/lib/sqlalchemy/pool/__init__.py
+++ b/lib/sqlalchemy/pool/__init__.py
@@ -22,36 +22,17 @@ from .base import _AdhocProxiedConnection
 from .base import _ConnectionFairy
 from .base import _ConnectionRecord
 from .base import _finalize_fairy
-from .base import Pool
-from .base import PoolProxiedConnection
-from .base import reset_commit
-from .base import reset_none
-from .base import reset_rollback
-from .impl import AssertionPool
-from .impl import AsyncAdaptedQueuePool
-from .impl import FallbackAsyncAdaptedQueuePool
-from .impl import NullPool
-from .impl import QueuePool
-from .impl import SingletonThreadPool
-from .impl import StaticPool
-
-
-__all__ = [
-    "Pool",
-    "PoolProxiedConnection",
-    "reset_commit",
-    "reset_none",
-    "reset_rollback",
-    "clear_managers",
-    "manage",
-    "AssertionPool",
-    "NullPool",
-    "QueuePool",
-    "AsyncAdaptedQueuePool",
-    "FallbackAsyncAdaptedQueuePool",
-    "SingletonThreadPool",
-    "StaticPool",
-]
-
-# as these are likely to be used in various test suites, debugging
-# setups, keep them in the sqlalchemy.pool namespace
+from .base import Pool as Pool
+from .base import PoolProxiedConnection as PoolProxiedConnection
+from .base import reset_commit as reset_commit
+from .base import reset_none as reset_none
+from .base import reset_rollback as reset_rollback
+from .impl import AssertionPool as AssertionPool
+from .impl import AsyncAdaptedQueuePool as AsyncAdaptedQueuePool
+from .impl import (
+    FallbackAsyncAdaptedQueuePool as FallbackAsyncAdaptedQueuePool,
+)
+from .impl import NullPool as NullPool
+from .impl import QueuePool as QueuePool
+from .impl import SingletonThreadPool as SingletonThreadPool
+from .impl import StaticPool as StaticPool