reftracker and idmapfile are highly specific to bzr-fastimport, and probably shouldn't be in this library

[Max Bowsher]

reftracker is some very specific code that implements a particular kind of ref-tracking in exactly the way bzr-fastimport wants it. I think it deserves reconsideration whether it should actually be factored out to a library, with the implicit commitment of maintaining a (relatively) stable API.

idmapfile is also code crafted for bzr-fastimport primarily, and is fairly confusing/meaningless outside that context - exactly what an "id map file" and why you would want one is only determined at the bzr-fastimport layer. (And for further confusion, the "id map file" has coincidentally the exact same formatting as a marks file.)

I think these two files should move back into bzr-fastimport unless there's an established need for something other that bzr-fastimport to do these things, in which case, the APIs of these modules could do with an overhaul and documentation before they go into a release.