[Kde-scm-interest] Git roadmap

[Paolo Capriotti]

On Tuesday 18 September 2007 13:09:06 Johannes Sixt wrote:
> >> I think there's a third possibility: actual copies with history across
> >> modules.
> >
> > more input, please.
>
> filter-branch --subdirectory followed by git merge -s subtree.
> See my other posts.

I did some tests, and this doesn't seem to work well, at least afaict. I'm no 
git expert, so please excuse me if I'm missing something obvious.
There are two problems:
1) When I do a git-merge -s subtree of a branch, git tries to guess how to 
shift the branch tree to fit in the current head, but inevitably fails if 
this is the first merge, i.e. the directory is not yet in the target 
repository. Since we just want to do the move (we don't need to merge further 
from the source branch) this means that the subtree strategy is not the right 
tool to use. Instead, following the git-gui merge thread on the git mailing 
list, I've found a neat trick to do such a move.
Suppose you want to move kapp from kdereview (where it is a submodule) to 
kdebase. You can do, inside the kdebase repository:
git remote add kapp /path/to/kapp/repo
git fetch kapp
git read-tree --prefix=kapp/ kapp/master
git checkout kapp
git rev-parse kapp/master > .git/MERGE_HEAD
git commit
If I understand it correctly, this should be more or less a manual merge where 
we overwrite kapp's content into the current head (no problem, because we're 
doing it on an empty dir). However, this way we can specify the target 
directory.
2) git-rev-list doesn't seem to follow changes to files in the merged subtree. 
If I do a "git rev-list HEAD -- kapp/main.cpp" I only get the subtree merge 
commit. What's the reason for this?

Paolo Capriotti