- assorted fixes raised by pypy 2.1beta2, but all of which are good

ideas in general:
  - pypy2.1 w/ sqlite3 is the first DBAPI we're seeing returning
    unicode in cursor.description without being py3k.  add a new on-connect
    check for this, if we get back a u"", just don't do description decoding,
    should be OK for now.
  - the set tests in test_collection were assuming the two sets would be ordered
    the same when it tested pop(), can't really assume that.
  - test_serializer gets worse and worse, pickle is just not really viable here,
    ding out pypy
  - pypy2.1b2 seems to allow cursor.lastrowid to work (or we changed something?)
  - pool._threadconns.current() is a weakref, it can be None
  - another one of those logging.handlers imports

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 3e8e96a42..b8c3768a8 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -191,6 +191,10 @@ class DefaultDialect(interfaces.Dialect):
 
         self.returns_unicode_strings = self._check_unicode_returns(connection)
 
+        if self.description_encoding is not None and \
+            self._check_unicode_description(connection):
+            self._description_decoder = self.description_encoding = None
+
         self.do_rollback(connection.connection)
 
     def on_connect(self):
@@ -248,6 +252,26 @@ class DefaultDialect(interfaces.Dialect):
         else:
             return unicode_for_varchar
 
+    def _check_unicode_description(self, connection):
+        # all DBAPIs on Py2K return cursor.description as encoded,
+        # until pypy2.1beta2 with sqlite, so let's just check it -
+        # it's likely others will start doing this too in Py2k.
+
+        if util.py2k and not self.supports_unicode_statements:
+            cast_to = util.binary_type
+        else:
+            cast_to = util.text_type
+
+        cursor = connection.connection.cursor()
+        cursor.execute(
+            cast_to(
+                expression.select([
+                    expression.literal_column("'x'").label("some_label")
+                ]).compile(dialect=self)
+            )
+        )
+        return isinstance(cursor.description[0][0], util.text_type)
+
     def type_descriptor(self, typeobj):
         """Provide a database-specific :class:`.TypeEngine` object, given
         the generic object which comes from the types module.