From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Fri, 1 Jul 2016 16:44:47 +0000 (-0400)
Subject: Preserve type for math negation
X-Git-Tag: rel_1_1_0b3~26
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5c60aaefd32a7bdee611fb340911409e0b8223ed;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Preserve type for math negation

Fixed issue in SQL math negation operator where the type of the
expression would no longer be the numeric type of the original.
This would cause issues where the type determined result set
behaviors.

Change-Id: If0e339614a3686e251235fc94b6f59310c4630a5
Fixes: #3735
---

diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index defee6d06e..8a6b6b3703 100644
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -18,6 +18,15 @@
 .. changelog::
     :version: 1.0.14
 
+    .. change::
+        :tags: bug, sql
+        :tickets: 3735
+
+        Fixed issue in SQL math negation operator where the type of the
+        expression would no longer be the numeric type of the original.
+        This would cause issues where the type determined result set
+        behaviors.
+
     .. change::
         :tags: bug, sql
         :tickets: 3728
diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py
index 7630a9821c..827492f10b 100644
--- a/lib/sqlalchemy/sql/default_comparator.py
+++ b/lib/sqlalchemy/sql/default_comparator.py
@@ -192,7 +192,7 @@ def _inv_impl(expr, op, **kw):
 
 def _neg_impl(expr, op, **kw):
     """See :meth:`.ColumnOperators.__neg__`."""
-    return UnaryExpression(expr, operator=operators.neg)
+    return UnaryExpression(expr, operator=operators.neg, type_=expr.type)
 
 
 def _match_impl(expr, op, other, **kw):
diff --git a/test/sql/test_operators.py b/test/sql/test_operators.py
index 5712d8f99e..b6e80de4ba 100644
--- a/test/sql/test_operators.py
+++ b/test/sql/test_operators.py
@@ -1999,6 +1999,12 @@ class NegationTest(fixtures.TestBase, testing.AssertsCompiledSQL):
             "SELECT mytable.myid, mytable.name FROM "
             "mytable WHERE mytable.myid != :myid_1 AND NOT mytable.name")
 
+    def test_negate_operator_type(self):
+        is_(
+            (-self.table1.c.myid).type,
+            self.table1.c.myid.type,
+        )
+
 
 class LikeTest(fixtures.TestBase, testing.AssertsCompiledSQL):
     __dialect__ = 'default'