[RFC] dirstate design update

[Andrew Bennetts]

Robert Collins wrote:
[...]
> 
> I think we should modify dirstate to be roughly the following for each
> line in the state file: Make the tuple (dirname, basename, fileid) be
> the unique key (rather than (dirname, basename, fileid).

Robert tells me he meant this to be:

"Make the tuple (dirname, basename, fileid) be the unique key (rather than
(dirname, basename))."

-Andrew.