[Sqlalchemy-tickets] [sqlalchemy] #2773: error when accessing history w/ backref + make_transient object

[sqlalchemy <mi...@zz...>]

#2773: error when accessing history w/ backref + make_transient object
--------------------+------------------------------------
 Reporter:  zzzeek  |           Owner:  zzzeek
     Type:  defect  |          Status:  new
 Priority:  high    |       Milestone:  0.8.xx
Component:  orm     |        Severity:  major - 1-3 hours
 Keywords:          |  Progress State:  in progress
--------------------+------------------------------------
 {{{
 #!python
 from sqlalchemy.orm import attributes, instrumentation
 from sqlalchemy.testing.assertions import eq_
 from mock import Mock

 class Post(object):
     def __init__(self, name):
         self.name = name
     __hash__ = None
     def __eq__(self, other):
         return other is not None and other.name == self.name

 class Blog(object):
     def __init__(self, name):
         self.name = name
     __hash__ = None
     def __eq__(self, other):
         return other is not None and other.name == self.name

 lazy_posts = Mock()

 instrumentation.register_class(Post)
 instrumentation.register_class(Blog)
 attributes.register_attribute(Post, 'blog', uselist=False,
         backref='posts', trackparent=True, useobject=True)
 attributes.register_attribute(Blog, 'posts', uselist=True,
         backref='blog', callable_=lazy_posts, trackparent=True,
         useobject=True)

 lazy_posts.return_value = attributes.PASSIVE_NO_RESULT

 b = Blog("blog 1")
 p = Post("post 1")

 state, dict_ = attributes.instance_state(b), attributes.instance_dict(b)

 # this sets up NEVER_SET on b.posts
 p.blog = b

 eq_(state.committed_state, {"posts": attributes.NEVER_SET})
 assert 'posts' not in dict_

 # then suppose the object was made transient again,
 # the lazy loader would return this
 lazy_posts.return_value = attributes.ATTR_EMPTY

 p2 = Post('asdf')
 p2.blog = b

 eq_(state.committed_state, {"posts": attributes.NEVER_SET})
 eq_(dict_['posts'], [p2])

 # then this would fail.
 eq_(
     Blog.posts.impl.get_history(state, dict_, passive=True),
     ([p2], [], [])
 )

 eq_(
     Blog.posts.impl.get_all_pending(state, dict_),
     [(attributes.instance_state(p2), p2)]
 )
 }}}

 {{{
 Traceback (most recent call last):
   File "test.py", line 54, in <module>
     Blog.posts.impl.get_history(state, dict_, passive=True),
   File "/Users/classic/dev/sqlalchemy/lib/sqlalchemy/orm/attributes.py",
 line 876, in get_history
     return History.from_collection(self, state, current)
   File "/Users/classic/dev/sqlalchemy/lib/sqlalchemy/orm/attributes.py",
 line 1345, in from_collection
     for c in original
 TypeError: 'symbol' object is not iterable
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2773>
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