Re: [RFC] Rebasing merges: a jorney to the ultimate solution (Road Clear)

[Igor Djordjevic <igor.d.djordjevic@gmail.com>]

Hi Dscho,

On 27/02/2018 17:21, Johannes Schindelin wrote:
> 
> Do you have any way to describe the idea in a simple, 3-5 lines long 
> paragraph?
> 
> So far, I just know that it is some sort of confusing criss-cross 
> cherry-picking and merging and stuff, but nothing in those steps
> shouts out to me what the *idea* is.
> 
> If it would be something like "recreate the old merge, with merge 
> conflicts and all, then generate the diff to the actual tree of the
> merge commit, then apply that to the newly-generated merge", I would
> understand.

It would be more along the lines of "(1) rebase old merge commit parents, 
(2) generate separate diff between old merge commit and each of its 
parents, (3) apply each diff to their corresponding newly rebased 
parent respectively (as a temporary commit, one per rebased parent), 
(4) merge these temporary commits to generate 'rebased' merge commit, 
(5) drop temporary commits, recording their parents as parents of 
'rebased' merge commit (instead of dropped temporary commits)".

Implementation wise, steps (2) and (3) could also be done by simply 
copying old merge commit _snapshot_ on top of each of its parents as 
a temporary, non-merge commit, then rebasing (cherry-picking) these 
temporary commits on top of their rebased parent commits to produce 
rebased temporary commits (to be merged for generating 'rebased' 
merge commit in step (4)).

Regards, Buga