Any plans/needs to extend the fast-import format?

[Eric Siegerman]

Ian Clatworthy wrote:
> feature basis-for-changes = (last-commit|last-command)

Nice, except that "last-commit" and "last-command" are
confusingly similar (only varying in the last 2-3 characters).
How about "last-commit" and "incremental"?

In a different message, Ian wrote:
> Nevertheless, the sad reality is that *every* tool generating a
> fast-import stream with renames or copies needs to be mega careful
about
> ordering FileCommands currently. 

And:
> [without "incremental"] The code in bzr
> fast-import would half in complexity as well.

implies that there's grief for importer tools as well.

I wonder whether a lot of the pain couldn't be factored out into
a pair of external filters, for converting fast-import streams
from last-commit to incremental and vice versa.  bzr-fast-export
and bzr-fast-import, for e.g., could drop support for 
"incremental" semantics, but still interact via the filters with
tools that required those.

  - Eric