Re: Git range merge (cherry-pick a range)

> 
> Playing around with GIT, we encountered the following strange situation for
> which we would
> like to have an answer:
> 
> Scenario
> ========
> 
> We want to merge the range B to D from branch B1 to master
> 
> Master:       o-
>                   \
> Branch B1:      A-B-C-D-E
> 

> 
> Commit B:
> ---------
> FluidSolver::FluidSolver(int argc, char* argv[]) {
>     init(argc, argv);
>     // test edit 1: a + b
> }
> 
> Commit C:
> --------
> FluidSolver::FluidSolver(int argc, char* argv[]) {
>     init(argc, argv);
>     // test edit 1: a + b
>     // test edit 2: a - b
> }
> 
> Commit D:
> --------
> FluidSolver::FluidSolver(int argc, char* argv[]) {
>     init(argc, argv);
>     // test edit 1: a + b
>     // test edit 2: a - b
>     // test edit 3: a * b
> }
> 
> Commit E:
> --------
> FluidSolver::FluidSolver(int argc, char* argv[]) {
>     init(argc, argv);
>     // test edit 1: a + b
>     // test edit 2: a - b
>     // test edit 3: a * b
>     // test edit 4: a / b
> }
> 
> 
> Range merge (the GIT way):
> =========================
> 
> 1) Switch to Branch B1
> 
> 2) Create a temporary branch which does not contain anything beyond commit D
> 
>    $ git checkout -b volatileBranch D
> 
>     Master:                 o-
>                                 \
>     Branch B1:                A-B-C-D-E
>                                                 \
>     Branch volatileBranch:              (A)-(B)-(C)-(D)
> 
> 3) Rebase volatile branch to master from commit (B) to master's HEAD
>    git rebase --onto master (A) 
> 
> 
>     Branch volatileBranch:   (B)-(C)-(D)
>                                      /
>     Master:                      o-
>                                      \
>     Branch B1:                   A-B-C-D-E
>                                        
> 
> Rebasing output:
> ----------------
> 
> First, rewinding head to replay your work on top of it...
> Applying: test edit 2: a - b
> error: patch failed: fluidsolver.cpp:28
> error: fluidsolver.cpp: patch does not apply
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> Auto-merging fluidsolver.cpp
> CONFLICT (content): Merge conflict in fluidsolver.cpp
> Failed to merge in the changes.
> Patch failed at 0001 test edit 2: a - b
> 
> 
> When you have resolved this problem run "git rebase --continue".
> If you would prefer to skip this patch, instead run "git rebase --skip".
> To restore the original branch and stop rebasing run "git rebase --abort".
> 
> 
> Conflicts:
> ----------
> FluidSolver::FluidSolver(int argc, char* argv[]) {
>     init(argc, argv);
> <<<<<<< HEAD:fluidsolver.cpp
> =======
>     // test edit 1: a + b
>     // test edit 2: a - b
>>>>>>>> test edit 2: a - b:fluidsolver.cpp
> }
> 
> 
> After manually resolving the conflict and continuing the rebasing 
> with git rebase --continue, we are finally finished.
> 
> Since we only had updates in branch 1, it is astonishing that we get a
> conflict at all.
> Same situation works like a charme in subversion.

> We would be happy to get an explanation for this merge bahaviour, since 
> many edits in large projects could as a matter of principle result a lot of
> merge conflicts
> which all have to be treated manually.
> 
> We believe that GIT's interface for range merges needs to get more user
> friendly.
> Since steps 1) - 3) use already developed components of GIT, there should be
> a layer above 'em
> which performs a range merge by internally calling 1) - 3).
> 
> Example: git cherry-pick $from_branch@startCommitHash
> $to_branch@endCommitHash 
>