From: John Passaro <john.a.passaro@gmail.com>
Date: Mon, 19 Sep 2016 19:43:46 +0000 (-0400)
Subject: Exclude eq and ne from associative operators
X-Git-Tag: rel_1_1_0~25^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c4119d1eb9e231676bf4facedf46849970b8253;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Exclude eq and ne from associative operators

The "eq" and "ne" operators are no longer part of the list of
"associative" operators, while they remain considered to be
"commutative".  This allows an expression like ``(x == y) == z``
to be maintained at the SQL level with parenthesis.  Pull request
courtesy John Passaro.

Fixes: #3799
Change-Id: I3759d8987b35649d7418b6524316c9e70c857e68
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/308
---

diff --git a/doc/build/changelog/changelog_11.rst b/doc/build/changelog/changelog_11.rst
index a097034891..4693eda29b 100644
--- a/doc/build/changelog/changelog_11.rst
+++ b/doc/build/changelog/changelog_11.rst
@@ -21,6 +21,16 @@
 .. changelog::
     :version: 1.1.0
 
+    .. change::
+        :tags: bug, sql
+        :tickets: 3799
+
+        The "eq" and "ne" operators are no longer part of the list of
+        "associative" operators, while they remain considered to be
+        "commutative".  This allows an expression like ``(x == y) == z``
+        to be maintained at the SQL level with parenthesis.  Pull request
+        courtesy John Passaro.
+
     .. change::
         :tags: bug, orm
         :tickets: 3788
diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index bf470710db..1426066804 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -917,7 +917,7 @@ def mirror(op):
     return _mirror.get(op, op)
 
 
-_associative = _commutative.union([concat_op, and_, or_])
+_associative = _commutative.union([concat_op, and_, or_]).difference([eq, ne])
 
 _natural_self_precedent = _associative.union([
     getitem, json_getitem_op, json_path_getitem_op])
diff --git a/test/sql/test_operators.py b/test/sql/test_operators.py
index b6e80de4ba..99f8a10ca3 100644
--- a/test/sql/test_operators.py
+++ b/test/sql/test_operators.py
@@ -1538,6 +1538,14 @@ class OperatorAssociativityTest(fixtures.TestBase, testing.AssertsCompiledSQL):
         f = column('f')
         self.assert_compile(f / (f / (f - f)), "f / (f / (f - f))")
 
+    def test_associativity_22(self):
+        f = column('f')
+        self.assert_compile((f==f) == f, '(f = f) = f')
+
+    def test_associativity_23(self):
+        f = column('f')
+        self.assert_compile((f!=f) != f, '(f != f) != f')
+
 
 class IsDistinctFromTest(fixtures.TestBase, testing.AssertsCompiledSQL):
     __dialect__ = 'default'