From 1c67b1ab8c6fe273d4e175a14f0df5d3cbbd0edc Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 2 Sep 2015 21:52:33 -0400
Subject: [PATCH] - Fixed issue in PG server default comparison where
 model-side defaults configured with Python unicode literals would leak the
 "u" character from a ``repr()`` into the SQL used for comparison, creating an
 invalid SQL expression, as the server-side comparison feature in PG currently
 repurposes the autogenerate Python rendering feature to get a quoted version
 of a plain string default. fixes #324

---
 alembic/__init__.py       |  2 +-
 alembic/ddl/postgresql.py |  3 ++-
 docs/build/changelog.rst  | 15 +++++++++++++++
 tests/test_postgresql.py  | 15 +++++++++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/alembic/__init__.py b/alembic/__init__.py
index 5645f100..bbd3e47f 100644
--- a/alembic/__init__.py
+++ b/alembic/__init__.py
@@ -1,6 +1,6 @@
 from os import path
 
-__version__ = '0.8.2'
+__version__ = '0.8.3'
 
 package_dir = path.abspath(path.dirname(__file__))
 
diff --git a/alembic/ddl/postgresql.py b/alembic/ddl/postgresql.py
index 5109b11f..39c380d1 100644
--- a/alembic/ddl/postgresql.py
+++ b/alembic/ddl/postgresql.py
@@ -47,7 +47,8 @@ class PostgresqlImpl(DefaultImpl):
                 not isinstance(inspector_column.type, Numeric):
                 # don't single quote if the column type is float/numeric,
                 # otherwise a comparison such as SELECT 5 = '5.0' will fail
-            rendered_metadata_default = "'%s'" % rendered_metadata_default
+            rendered_metadata_default = re.sub(
+                r"^u?'?|'?$", "'", rendered_metadata_default)
 
         return not self.connection.scalar(
             "SELECT %s = %s" % (
diff --git a/docs/build/changelog.rst b/docs/build/changelog.rst
index 27006da5..96fdabce 100644
--- a/docs/build/changelog.rst
+++ b/docs/build/changelog.rst
@@ -3,6 +3,21 @@
 Changelog
 ==========
 
+.. changelog::
+    :version: 0.8.3
+
+    .. change::
+      :tags: bug, autogenerate, postgresql
+      :tickets: 324
+
+      Fixed issue in PG server default comparison where model-side defaults
+      configured with Python unicode literals would leak the "u" character
+      from a ``repr()`` into the SQL used for comparison, creating an invalid
+      SQL expression, as the server-side comparison feature in PG currently
+      repurposes the autogenerate Python rendering feature to get a quoted
+      version of a plain string default.
+
+
 .. changelog::
     :version: 0.8.2
     :released: August 25, 2015
diff --git a/tests/test_postgresql.py b/tests/test_postgresql.py
index 576d957a..21ba6b9e 100644
--- a/tests/test_postgresql.py
+++ b/tests/test_postgresql.py
@@ -331,6 +331,21 @@ class PostgresqlDefaultCompareTest(TestBase):
             diff_expected=False
         )
 
+    def test_compare_unicode_literal(self):
+        self._compare_default_roundtrip(
+            String(),
+            u'im a default'
+        )
+
+    # TOOD: will need to actually eval() the repr() and
+    # spend more effort figuring out exactly the kind of expression
+    # to use
+    def _TODO_test_compare_character_str_w_singlequote(self):
+        self._compare_default_roundtrip(
+            String(),
+            "hel''lo",
+        )
+
     def test_compare_character_str(self):
         self._compare_default_roundtrip(
             String(),
-- 
2.47.2