memoize current options and joins w with_entities/with_only_cols

Fixed further regressions in the same area as that of :ticket:`6052` where
loader options as well as invocations of methods like
:meth:`_orm.Query.join` would fail if the left side of the statement for
which the option/join depends upon were replaced by using the
:meth:`_orm.Query.with_entities` method, or when using 2.0 style queries
when using the :meth:`_sql.Select.with_only_columns` method. A new set of
state has been added to the objects which tracks the "left" entities that
the options / join were made against which is memoized when the lead
entities are changed.

Fixes: #6503
Fixes: #6253
Change-Id: I211b2af98b0b20d1263fb15dc513884dcc5de6a4

1 files changed, 23 insertions, 0 deletions

diff --git a/test/sql/test_external_traversal.py b/test/sql/test_external_traversal.py
index 3469dcb37..c7e51c807 100644
--- a/test/sql/test_external_traversal.py
+++ b/test/sql/test_external_traversal.py
@@ -1747,6 +1747,29 @@ class ClauseAdapterTest(fixtures.TestBase, AssertsCompiledSQL):
             "addresses.user_id",
         )
 
+    def test_prev_entities_adapt(self):
+        """test #6503"""
+
+        m = MetaData()
+        users = Table("users", m, Column("id", Integer, primary_key=True))
+        addresses = Table(
+            "addresses",
+            m,
+            Column("id", Integer, primary_key=True),
+            Column("user_id", ForeignKey("users.id")),
+        )
+
+        ualias = users.alias()
+
+        s = select(users).join(addresses).with_only_columns(addresses.c.id)
+        s = sql_util.ClauseAdapter(ualias).traverse(s)
+
+        self.assert_compile(
+            s,
+            "SELECT addresses.id FROM users AS users_1 "
+            "JOIN addresses ON users_1.id = addresses.user_id",
+        )
+
     @testing.combinations((True,), (False,), argnames="use_adapt_from")
     def test_table_to_alias_1(self, use_adapt_from):
         t1alias = t1.alias("t1alias")