From 337d8803050e77e88bc73547f2e862cdb80dd188 Mon Sep 17 00:00:00 2001
From: David Szotten <davidszotten@gmail.com>
Date: Fri, 17 Jun 2016 12:54:57 -0400
Subject: [PATCH] Include DateTime.timezone in autogen type comparisons

Change-Id: I2e5b380625ec45d5ebc0bc74daf9cf9e05f0155a
Pull-request: https://github.com/zzzeek/alembic/pull/26
---
 alembic/ddl/impl.py         | 10 +++++++++-
 docs/build/changelog.rst    |  7 +++++++
 tests/test_autogen_diffs.py | 10 ++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/alembic/ddl/impl.py b/alembic/ddl/impl.py
index d87a2fcb..56b4d59c 100644
--- a/alembic/ddl/impl.py
+++ b/alembic/ddl/impl.py
@@ -350,8 +350,16 @@ def _integer_compare(t1, t2):
     )
     return t1_small_or_big != t2_small_or_big
 
+
+def _datetime_compare(t1, t2):
+    return (
+        t1.timezone != t2.timezone
+    )
+
+
 _type_comparators = {
     sqltypes.String: _string_compare,
     sqltypes.Numeric: _numeric_compare,
-    sqltypes.Integer: _integer_compare
+    sqltypes.Integer: _integer_compare,
+    sqltypes.DateTime: _datetime_compare,
 }
diff --git a/docs/build/changelog.rst b/docs/build/changelog.rst
index ebd54fda..cd9ce411 100644
--- a/docs/build/changelog.rst
+++ b/docs/build/changelog.rst
@@ -15,6 +15,13 @@ Changelog
       :paramref:`.op.alter_column.postgresql_using`
       parameter.  Pull request courtesy Frazer McLean.
 
+    .. change:
+      :tags: feature, autogenerate
+
+      Autogenerate with type comparison enabled will pick up on the timezone
+      setting changing between DateTime types.   Pull request courtesy
+      David Szotten.
+
 .. changelog::
     :version: 0.8.7
     :released: July 26, 2016
diff --git a/tests/test_autogen_diffs.py b/tests/test_autogen_diffs.py
index c2c385de..04c9e967 100644
--- a/tests/test_autogen_diffs.py
+++ b/tests/test_autogen_diffs.py
@@ -630,6 +630,16 @@ class CompareTypeSpecificityTest(TestBase):
         is_(impl.compare_type(Column('x', t5), Column('x', t2)), True)
         is_(impl.compare_type(Column('x', t1), Column('x', t4)), True)
 
+    def test_datetime(self):
+        t1 = DateTime()
+        t2 = DateTime(timezone=False)
+        t3 = DateTime(timezone=True)
+
+        impl = self._fixture()
+        is_(impl.compare_type(Column('x', t1), Column('x', t2)), False)
+        is_(impl.compare_type(Column('x', t1), Column('x', t3)), True)
+        is_(impl.compare_type(Column('x', t2), Column('x', t3)), True)
+
 
 class AutogenerateCustomCompareTypeTest(AutogenTest, TestBase):
     __only_on__ = 'sqlite'
-- 
2.47.2