Improve rendering of core statements w/ ORM elements

This patch contains a variety of ORM and expression layer
tweaks to support ORM constructs in select() statements,
without the 1.3.x requiremnt in Query that a full
_compile_context() + new select() is needed in order to
get a working statement object.

Includes such tweaks as the ability to implement
aliased class of an aliased class,
as we are looking to fully support ACs against subqueries,
as well as the ability to access anonymously-labeled
ColumnProperty expressions within subqueries by
naming the ".key" of the label after the property
key.   Some tuning to query.join() as well
as ORMJoin internals to allow things to work more
smoothly.

Change-Id: Id810f485c5f7ed971529489b84694e02a3356d6d

1 files changed, 41 insertions, 0 deletions

diff --git a/test/sql/test_utils.py b/test/sql/test_utils.py
index 4e713dd28..d68a74475 100644
--- a/test/sql/test_utils.py
+++ b/test/sql/test_utils.py
@@ -4,8 +4,11 @@ from sqlalchemy import MetaData
 from sqlalchemy import select
 from sqlalchemy import String
 from sqlalchemy import Table
+from sqlalchemy.sql import base as sql_base
 from sqlalchemy.sql import util as sql_util
 from sqlalchemy.sql.elements import ColumnElement
+from sqlalchemy.testing import assert_raises
+from sqlalchemy.testing import assert_raises_message
 from sqlalchemy.testing import eq_
 from sqlalchemy.testing import fixtures
 
@@ -48,3 +51,41 @@ class MiscTest(fixtures.TestBase):
             set(sql_util.find_tables(subset_select, include_aliases=True)),
             {common, calias, subset_select},
         )
+
+    def test_options_merge(self):
+        class opt1(sql_base.CacheableOptions):
+            _cache_key_traversal = []
+
+        class opt2(sql_base.CacheableOptions):
+            _cache_key_traversal = []
+
+            foo = "bar"
+
+        class opt3(sql_base.CacheableOptions):
+            _cache_key_traversal = []
+
+            foo = "bar"
+            bat = "hi"
+
+        o2 = opt2.safe_merge(opt1)
+        eq_(o2.__dict__, {})
+        eq_(o2.foo, "bar")
+
+        assert_raises_message(
+            TypeError,
+            r"other element .*opt2.* is not empty, is not of type .*opt1.*, "
+            r"and contains attributes not covered here .*'foo'.*",
+            opt1.safe_merge,
+            opt2,
+        )
+
+        o2 = opt2 + {"foo": "bat"}
+        o3 = opt2.safe_merge(o2)
+
+        eq_(o3.foo, "bat")
+
+        o4 = opt3.safe_merge(o2)
+        eq_(o4.foo, "bat")
+        eq_(o4.bat, "hi")
+
+        assert_raises(TypeError, opt2.safe_merge, o4)