Will re-basing support be added into Bazaar core ?

[Stephen J. Turnbull]

Ben Finney writes:

 > As fasr as I can tell from what you're saying, the design of Bazaar's
 > loom *is* to provide "every commit is (able to be) tested" and
 > "revise patches for upstream changes" simultaneously. So, since you
 > say you can't see how that's possible, I would direct you that way.

What Linus pointed out is that if you have a divergent pair of
branches where C (the common ancestor) is tested and the branches A
and B have both been tested, it's easy to forget that when you rebase
B on top of A, all of your tests for A, B, and C have been invalidated
and you have to run the whole suite again.[1]

This is just as true of looms but worse, because of the combinatorial
explosion of "realizations" of the loom.  (By "realization" I mean a
workspace containing a specific list of threads in their various
states.)

Footnotes: 
[1]  Not entirely true.  Of course you don't need to run unit tests
for other modules again, but you do have to run the unit tests for all
modules that are not identical in A and B.  And of course all
integration tests must be run.