Deprecate connection branching

The :meth:`.Connection.connect` method is deprecated as is the concept of
"connection branching", which copies a :class:`.Connection` into a new one
that has a no-op ".close()" method.  This pattern is oriented around the
"connectionless execution" concept which is also being removed in 2.0.

As part of this change we begin to move the internals away from
"connectionless execution" overall.   Remove the "connectionless
execution" concept from the reflection internals and replace with
explicit patterns at the Inspector level.

Fixes: #5131
Change-Id: Id23d28a9889212ac5ae7329b85136157815d3e6f

3 files changed, 6 insertions, 2 deletions

diff --git a/lib/sqlalchemy/testing/__init__.py b/lib/sqlalchemy/testing/__init__.py
index ab1198da8..582901579 100644
--- a/lib/sqlalchemy/testing/__init__.py
+++ b/lib/sqlalchemy/testing/__init__.py
@@ -20,6 +20,7 @@ from .assertions import eq_  # noqa
 from .assertions import eq_ignore_whitespace  # noqa
 from .assertions import eq_regex  # noqa
 from .assertions import expect_deprecated  # noqa
+from .assertions import expect_deprecated_20  # noqa
 from .assertions import expect_warnings  # noqa
 from .assertions import in_  # noqa
 from .assertions import is_  # noqa
diff --git a/lib/sqlalchemy/testing/assertions.py b/lib/sqlalchemy/testing/assertions.py
index c74259bdf..d055ba86e 100644
--- a/lib/sqlalchemy/testing/assertions.py
+++ b/lib/sqlalchemy/testing/assertions.py
@@ -81,6 +81,10 @@ def expect_deprecated(*messages, **kw):
     return _expect_warnings(sa_exc.SADeprecationWarning, messages, **kw)
 
 
+def expect_deprecated_20(*messages, **kw):
+    return _expect_warnings(sa_exc.RemovedIn20Warning, messages, **kw)
+
+
 def emits_warning_on(db, *messages):
     """Mark a test as emitting a warning on a specific dialect.
 
diff --git a/lib/sqlalchemy/testing/suite/test_reflection.py b/lib/sqlalchemy/testing/suite/test_reflection.py
index f9ff46492..d375f0279 100644
--- a/lib/sqlalchemy/testing/suite/test_reflection.py
+++ b/lib/sqlalchemy/testing/suite/test_reflection.py
@@ -21,7 +21,6 @@ from ... import MetaData
 from ... import String
 from ... import testing
 from ... import types as sql_types
-from ...engine.reflection import Inspector
 from ...schema import DDL
 from ...schema import Index
 from ...sql.elements import quoted_name
@@ -661,7 +660,7 @@ class ComponentReflectionTest(fixtures.TablesTest):
     def test_deprecated_get_primary_keys(self):
         meta = self.metadata
         users = self.tables.users
-        insp = Inspector(meta.bind)
+        insp = inspect(meta.bind)
         assert_raises_message(
             sa_exc.SADeprecationWarning,
             r".*get_primary_keys\(\) method is deprecated",