From cad2dafa730f0d33a57a6f7483f8f08b297f277c Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 29 Jun 2016 16:22:24 -0400
Subject: [PATCH] Don't remove None for default schema of None

Fixed bug in autogen where if the DB connection sends the default
schema as "None", this "None" would be removed from the list of
schemas to check if include_schemas were set.  This could possibly
impact using include_schemas with SQLite.

Change-Id: I553cdbbe2cfaa5228d86019e14f7c9f56231f295
---
 alembic/autogenerate/compare.py |  2 +-
 docs/build/changelog.rst        |  8 ++++++++
 tests/test_autogen_diffs.py     | 31 ++++++++++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/alembic/autogenerate/compare.py b/alembic/autogenerate/compare.py
index a4e5f7bd..1b721b03 100644
--- a/alembic/autogenerate/compare.py
+++ b/alembic/autogenerate/compare.py
@@ -39,8 +39,8 @@ def _produce_net_changes(autogen_context, upgrade_ops):
         # replace default schema name with None
         schemas.discard("information_schema")
         # replace the "default" schema with None
-        schemas.add(None)
         schemas.discard(default_schema)
+        schemas.add(None)
     else:
         schemas = [None]
 
diff --git a/docs/build/changelog.rst b/docs/build/changelog.rst
index ed4e29d5..1308a293 100644
--- a/docs/build/changelog.rst
+++ b/docs/build/changelog.rst
@@ -6,6 +6,14 @@ Changelog
 .. changelog::
     :version: 0.8.7
 
+    .. change::
+      :tags: bug, autogenerate
+
+      Fixed bug in autogen where if the DB connection sends the default
+      schema as "None", this "None" would be removed from the list of
+      schemas to check if include_schemas were set.  This could possibly
+      impact using include_schemas with SQLite.
+
     .. change::
       :tags: bug, batch
 
diff --git a/tests/test_autogen_diffs.py b/tests/test_autogen_diffs.py
index 6887058f..c2c385de 100644
--- a/tests/test_autogen_diffs.py
+++ b/tests/test_autogen_diffs.py
@@ -14,7 +14,7 @@ from alembic.migration import MigrationContext
 from alembic.testing import TestBase
 from alembic.testing import config
 from alembic.testing import assert_raises_message
-from alembic.testing.mock import Mock
+from alembic.testing.mock import Mock, patch
 from alembic.testing import eq_, is_, is_not_
 from alembic.util import CommandError
 from ._autogen_fixtures import AutogenTest, AutogenFixtureTest
@@ -188,6 +188,35 @@ class AutogenDefaultSchemaTest(AutogenFixtureTest, TestBase):
         eq_(diffs[0][1].c.keys(), ['x'])
 
 
+class AutogenDefaultSchemaIsNoneTest(AutogenFixtureTest, TestBase):
+    __only_on__ = 'sqlite'
+
+    def setUp(self):
+        super(AutogenDefaultSchemaIsNoneTest, self).setUp()
+
+        # prerequisite
+        eq_(self.bind.dialect.default_schema_name, None)
+
+    def test_no_default_schema(self):
+
+        m1 = MetaData()
+        m2 = MetaData()
+
+        Table('a', m1, Column('x', String(50)))
+        Table('a', m2, Column('x', String(50)))
+
+        def _include_object(obj, name, type_, reflected, compare_to):
+            if type_ == "table":
+                return name in 'a' and obj.schema != 'main'
+            else:
+                return True
+
+        diffs = self._fixture(
+            m1, m2, include_schemas=True,
+            object_filters=_include_object)
+        eq_(len(diffs), 0)
+
+
 class ModelOne(object):
     __requires__ = ('unique_constraint_reflection', )
 
-- 
2.47.2