Re: Best way to generate a git tree containing only a subset of commits from another tree?

Anton Altaparmakov wrote:

git format-patch -k <start-commit>..<end-commit> --stdout | git am -k

Make sure you're on the right branch first, but see below.

I sense some nomenclature confusion here. By "tree", do you happen to mean "branch", or possibly "repository"? I know bk does things with trees that's vaguely git-ish, but a tree in git is, basically, just a simplified directory listing (without depth, although it can contain other trees ad infinitum iiuc).

If you mean "branch" (or repository, it doesn't matter since by then you'll have something like a master branch anyway), as I think you do, then let's assume the Vanilla Linux lives in the "linus" branch.

You would then do

    $ git checkout -b for-linus linus

followed by either multiple
    $ git cherry-pick <commit-ish>

or, if the commits are all in series, an iteration of the following

    $ git format-patch --stdout <start-commit>..<end-commit> | git am -k

If you have several topic branches, one for each series of commits, you 
should be able to do an octopus, like so:
    $ git pull . <topic-branches-to-publish>

If you *don't* have several topic branches, or if some commits aren't in topic-branches, you could try something like this (untested, although it shouldn't break anything except the for-linus branch which you can re-create fairly simply)

   $ for b in <topic-branches-for-linus>; do
       git checkout $b
       git rebase for-linus || (git reset --hard; echo $b >> to-merge)
     done
   # now merge what couldn't be rebased
   $ git checkout for-linus
   $ git pull . $(cat to-merge)

In your "please-pull" mail to Linus, ask him to pull the 'for-linus' 
branch. When he's done so, pull his 'master' branch to your 'linus', 
branch and remove the 'for-linus' branch and re-create it from Linus' 
master branch again. If your vanilla tree is up-to-date and he pulls 
from you before pulling from someone else or adding other commits this 
isn't necessary, although you'll have to do
    $ git checkout linus; git pull . for-linus

to get the vanilla branch up to speed with Linus' HEAD.

That turned out a bit longer than I expected, and with me being slightly off sobriety at the moment it would be good if someone less so could double-check the thinking. Incidentally, this is one of the reasons why topic-branches is such a Good Thing (tm).

I hope so, or I just spent a good 20 minutes not drinking beer for nothing. ;)

It's worth re-iterating: git format-patch --stdout -k <start-commit>..<end-commit> > patch-series git am -k patch-series

It will save you a lot of work.

Hopefully I just supplied one that can be re-used with some text-mangling by someone capable of being legible and making sense at the same time.

For more info, check out the man-pages of the commands above (notably the cherry-pick man-page and the pull command's "merge with local" feature).