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, 60 insertions, 0 deletions

diff --git a/test/sql/test_selectable.py b/test/sql/test_selectable.py
index e509c9f95..d53ee3385 100644
--- a/test/sql/test_selectable.py
+++ b/test/sql/test_selectable.py
@@ -147,6 +147,66 @@ class SelectableTest(
         assert s1.corresponding_column(scalar_select) is s1.c.foo
         assert s2.corresponding_column(scalar_select) is s2.c.foo
 
+    def test_labels_name_w_separate_key(self):
+        label = select([table1.c.col1]).label("foo")
+        label.key = "bar"
+
+        s1 = select([label])
+        assert s1.corresponding_column(label) is s1.selected_columns.bar
+
+        # renders as foo
+        self.assert_compile(
+            s1, "SELECT (SELECT table1.col1 FROM table1) AS foo"
+        )
+
+    def test_labels_anon_w_separate_key(self):
+        label = select([table1.c.col1]).label(None)
+        label.key = "bar"
+
+        s1 = select([label])
+
+        # .bar is there
+        assert s1.corresponding_column(label) is s1.selected_columns.bar
+
+        # renders as anon_1
+        self.assert_compile(
+            s1, "SELECT (SELECT table1.col1 FROM table1) AS anon_1"
+        )
+
+    def test_labels_anon_w_separate_key_subquery(self):
+        label = select([table1.c.col1]).label(None)
+        label.key = label._key_label = "bar"
+
+        s1 = select([label])
+
+        subq = s1.subquery()
+
+        s2 = select([subq]).where(subq.c.bar > 5)
+        self.assert_compile(
+            s2,
+            "SELECT anon_2.anon_1 FROM (SELECT (SELECT table1.col1 "
+            "FROM table1) AS anon_1) AS anon_2 "
+            "WHERE anon_2.anon_1 > :param_1",
+            checkparams={"param_1": 5},
+        )
+
+    def test_labels_anon_generate_binds_subquery(self):
+        label = select([table1.c.col1]).label(None)
+        label.key = label._key_label = "bar"
+
+        s1 = select([label])
+
+        subq = s1.subquery()
+
+        s2 = select([subq]).where(subq.c[0] > 5)
+        self.assert_compile(
+            s2,
+            "SELECT anon_2.anon_1 FROM (SELECT (SELECT table1.col1 "
+            "FROM table1) AS anon_1) AS anon_2 "
+            "WHERE anon_2.anon_1 > :param_1",
+            checkparams={"param_1": 5},
+        )
+
     def test_select_label_grouped_still_corresponds(self):
         label = select([table1.c.col1]).label("foo")
         label2 = label.self_group()