emberjs/data — pull request #340 by lukemelia (2012-07-22 06:37:47+00:00)
Title: Dirty relationships correctly when modifying belongsTo side of a belongsTo-hasMany relationship

Here's a first pass at this, base on my conversation with @wycats today.

In our app, this change (in combination with implementing shouldCommit on our adapter) makes setting a belongsTo attribute work as expected, except... the record that gets updated via the API never gets removed from the transaction. That results in an error the next time I try to add it to a transaction, since a record can only be a member of one transaction at a time.