Repair clauselist comparison to account for clause ordering

Fixed bug where the "simple many-to-one" condition that allows  lazy
loading to use get() from identity map would fail to be  invoked if the
primaryjoin of the relationship had multiple clauses separated by AND
which were not in the same order as that of the primary key columns
being compared in each clause. This ordering
difference occurs for a composite foreign key where the table-bound
columns on the referencing side were not in the same order in the .c
collection as the primary key columns on the referenced side....which
in turn occurs a lot if one is using declarative mixins and/or
declared_attr to set up columns.

Change-Id: I66cce74f614c04ed693dc0d58ac8c952b2f8ae54
Fixes: #3788

1 files changed, 78 insertions, 0 deletions

diff --git a/test/sql/test_utils.py b/test/sql/test_utils.py
new file mode 100644
index 000000000..09d7e98af
--- /dev/null
+++ b/test/sql/test_utils.py
@@ -0,0 +1,78 @@
+from sqlalchemy.testing import fixtures, is_true, is_false
+from sqlalchemy import MetaData, Table, Column, Integer
+from sqlalchemy import and_, or_
+from sqlalchemy.sql.elements import ClauseList
+from sqlalchemy.sql import operators
+
+
+class CompareClausesTest(fixtures.TestBase):
+    def setup(self):
+        m = MetaData()
+        self.a = Table(
+            'a', m,
+            Column('x', Integer),
+            Column('y', Integer)
+        )
+
+        self.b = Table(
+            'b', m,
+            Column('y', Integer),
+            Column('z', Integer)
+        )
+
+    def test_compare_clauselist_associative(self):
+
+        l1 = and_(
+            self.a.c.x == self.b.c.y,
+            self.a.c.y == self.b.c.z
+        )
+
+        l2 = and_(
+            self.a.c.y == self.b.c.z,
+            self.a.c.x == self.b.c.y,
+        )
+
+        l3 = and_(
+            self.a.c.x == self.b.c.z,
+            self.a.c.y == self.b.c.y
+        )
+
+        is_true(l1.compare(l1))
+        is_true(l1.compare(l2))
+        is_false(l1.compare(l3))
+
+    def test_compare_clauselist_not_associative(self):
+
+        l1 = ClauseList(
+            self.a.c.x, self.a.c.y, self.b.c.y, operator=operators.sub)
+
+        l2 = ClauseList(
+            self.b.c.y, self.a.c.x, self.a.c.y, operator=operators.sub)
+
+        is_true(l1.compare(l1))
+        is_false(l1.compare(l2))
+
+    def test_compare_clauselist_assoc_different_operator(self):
+
+        l1 = and_(
+            self.a.c.x == self.b.c.y,
+            self.a.c.y == self.b.c.z
+        )
+
+        l2 = or_(
+            self.a.c.y == self.b.c.z,
+            self.a.c.x == self.b.c.y,
+        )
+
+        is_false(l1.compare(l2))
+
+    def test_compare_clauselist_not_assoc_different_operator(self):
+
+        l1 = ClauseList(
+            self.a.c.x, self.a.c.y, self.b.c.y, operator=operators.sub)
+
+        l2 = ClauseList(
+            self.a.c.x, self.a.c.y, self.b.c.y, operator=operators.div)
+
+        is_false(l1.compare(l2))
+