[Gnu-arch-users] merging use-case

[Robert Anderson]

I am collaborating with a group who is extending some software of
mine.

They are adding features that only _may_ be merged back into my
mainline, and I certainly don't want them futzing with it in my
mainline branch while they develop.

So they have their own branch.  I have read access to this
branch, but I do not have write access because I am not on that
project.

However, they want to stay up-to-date with the progression of the
mainline (my project.)

They have done some development which textually conflicts with
mine.  We are up to a point where they want to merge my latest
changes, but this merge will involve conflicts that I understand
how to fix easily, but they don't.  Therefore, I want to fix up
the conflicts for them, to make the merge as painless as possible
for them.

Is there some kind of "integration branch" process I can use here
that will generate a painless one-step conflictless merge for
them, that will also leave their tree in such a state that
further non-conflicting changes on my mainline will merge cleanly
for them using star-merge?

My thought here is to tag their latest, star-merge my changes
from mainline, fix up the conflicts, commit, then have them
star-merge that branch.  I'm just not sure if that leaves their
tree in the desired state:  the requirement is that further
commits to the mainline should be cleanly star-merge'able into
their branch.

Sanity check?

Bob