[elephant-devel] (FIXED) Bug where btree/dup-btrees are "oid: nil" in SBCL/BDB

[Ian Eslick]

Alex's recent question about why dup-btrees were persistent-metaclass  
along with a project of my own led me to the previously reported bug  
about deserializing btrees that had a nil in the oid slot.  This is  
related to the reason that dup-btrees were originally persistent- 
metaclass.

The class recreation protocol involves a generic function that  
dispatches on the class, not the instance, of the object to be  
recreated.  This means that 'persistent' vs. non-persistent isn't the  
easiest distinction to make.  The recreation function calls a special  
initialization for persistent-metaclass instances (i.e. oid & spec)  
which wasn't getting called for btree and dup-btree.

For now, I've added a call to initialize persistent in the controller  
recreation protocol to handle persistent-collections properly.  (for  
indexes and indexed-btrees this will get called twice).  I probably  
need to think through how to make this protocol cleaner since we  
really want to dispatch on (subtypep class 'persistent) at recreation  
time.

Anyway, this case is what led to the bug about oid:nil in btrees  
reported by Leslie and others earlier and the fix I just pushed should  
take care of that bug (which means Leslie should be able to start his  
testing of elephant-unstable again).

Ian