From 389325099d4d8c0ce42a5a0d5395fbe3ead15af5 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Mon, 22 Oct 2012 13:54:39 -0400
Subject: [PATCH] - fix regression from 0.7 where calling get_history with
 passive on a never-set collection would fail; made this act just like scalars
 for now and added tests.  I would think that HISTORY_BLANK would be more
 appropriate here but it's too late in the game to mess with that.

---
 lib/sqlalchemy/orm/attributes.py |  4 ++++
 test/orm/test_attributes.py      | 22 ++++++++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index eec72b5f33..86da9a61d1 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -1216,6 +1216,10 @@ class History(History):
     @classmethod
     def from_collection(cls, attribute, state, current):
         original = state.committed_state.get(attribute.key, _NO_HISTORY)
+
+        if current is NO_VALUE or current is NEVER_SET:
+            return cls((), (), ())
+
         current = getattr(current, '_sa_adapter')
         if original is NO_VALUE:
             return cls(list(current), (), ())
diff --git a/test/orm/test_attributes.py b/test/orm/test_attributes.py
index 46b1a6c3b0..1fc70fd77b 100644
--- a/test/orm/test_attributes.py
+++ b/test/orm/test_attributes.py
@@ -1382,10 +1382,10 @@ class HistoryTest(fixtures.TestBase):
                 useobject=True)
         return Foo, Bar
 
-    def _someattr_history(self, f):
+    def _someattr_history(self, f, **kw):
         return attributes.get_state_history(
                     attributes.instance_state(f),
-                    'someattr')
+                    'someattr', **kw)
 
     def _commit_someattr(self, f):
         attributes.instance_state(f)._commit(attributes.instance_dict(f),
@@ -1553,6 +1553,24 @@ class HistoryTest(fixtures.TestBase):
         assert 'someattr' not in f.__dict__
         assert 'someattr' not in attributes.instance_state(f).committed_state
 
+    def test_collection_never_set(self):
+        Foo = self._fixture(uselist=True, useobject=True,
+                                active_history=True)
+        f = Foo()
+        eq_(self._someattr_history(f, passive=True), ((), (), ()))
+
+    def test_scalar_obj_never_set(self):
+        Foo = self._fixture(uselist=False, useobject=True,
+                                active_history=True)
+        f = Foo()
+        eq_(self._someattr_history(f, passive=True), ((), (), ()))
+
+    def test_scalar_never_set(self):
+        Foo = self._fixture(uselist=False, useobject=False,
+                                active_history=True)
+        f = Foo()
+        eq_(self._someattr_history(f, passive=True), ((), (), ()))
+
     def test_scalar_active_set(self):
         Foo = self._fixture(uselist=False, useobject=False,
                                 active_history=True)
-- 
2.47.3