[tahoe-dev] notes about DIR2:CHK deep immutability (maybe Tahoe-LAFS v1.6)

[Kevin Reid]

On Oct 21, 2009, at 1:27, Zooko Wilcox-O'Hearn wrote:

> When you create a DIR2:IMM, giving it a set of (childname, childcap)
> tuples, it should raise an exception if any childcap is not
> immutable.  The immutable childcaps are "CHK" (perhaps renamed to
> "IMM"), LIT, and DIR2:CHK (or "DIR2:IMM").


This seems overly restrictive. For example, I can't create a dircap  
which demonstrably permanently refers to a given file, and also to a  
mutable directory. I don't have any use-cases offhand, though.

Even if that isn't relevant, IMO there should be at least a utility  
which is "give me either a deep-immutable directory if possible, or a  
mutable directory to which the write key has been discarded" so that  
one can bundle a given set of caps without worrying about what their  
types are.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>