Remove threadlocal engine strategy, engine strategies pool threadlocal

The "threadlocal" execution strategy, deprecated in 1.3, has been
removed for 1.4, as well as the concept of "engine strategies" and the
``Engine.contextual_connect`` method.  The "strategy='mock'" keyword
argument is still accepted for now with a deprecation warning; use
:func:`.create_mock_engine` instead for this use case.

Fixes: #4632
Change-Id: I8a351f9fa1f7dfa2a56eec1cd2d1a4b9d65765a2
(cherry picked from commit b368c49b44c5716d93c7428ab22b6761c6ca7cf5)

1 files changed, 0 insertions, 24 deletions

diff --git a/lib/sqlalchemy/engine/interfaces.py b/lib/sqlalchemy/engine/interfaces.py
index aadadb845..4a63e3d84 100644
--- a/lib/sqlalchemy/engine/interfaces.py
+++ b/lib/sqlalchemy/engine/interfaces.py
@@ -1125,30 +1125,6 @@ class Connectable(object):
     """
 
     @util.deprecated(
-        "1.3",
-        "The :meth:`.Engine.contextual_connect` and "
-        ":meth:`.Connection.contextual_connect` methods are deprecated.  This "
-        "method is an artifact of the threadlocal engine strategy which is "
-        "also to be deprecated.   For explicit connections from an "
-        ":class:`.Engine`, use the :meth:`.Engine.connect` method.",
-    )
-    def contextual_connect(self, *arg, **kw):
-        """Return a :class:`.Connection` object which may be part of an ongoing
-        context.
-
-        Depending on context, this may be ``self`` if this object
-        is already an instance of :class:`.Connection`, or a newly
-        procured :class:`.Connection` if this object is an instance
-        of :class:`.Engine`.
-
-        """
-
-        return self._contextual_connect(*arg, **kw)
-
-    def _contextual_connect(self):
-        raise NotImplementedError()
-
-    @util.deprecated(
         "0.7",
         "The :meth:`.Connectable.create` method is deprecated and will be "
         "removed in a future release.  Please use the ``.create()`` method "