git cherry-pick or merge specific directory from another branch

Question

I've seen different posts on StackOverflow that explain cherry picking a bit, but the comments in their code aren't very specific as to what's a branch and what's a directory. Example git checkout A -- X Y doesn't tell me much.

Basically I want this:

• Create new branch featureA off of master
• Merge directory /tools/my-tool from branch dev into featureA

Answer 1

To answer the original question about how to cherry-pick some directories (as commits instead of a brute-force checkout), this is possible. Imagine that featureA has diverged from master and you want to bring over the tools/my-tool commits.

Assuming that you never made any commits that contain both stuff from /tools/my-tool and stuff from other directories

This will get you the list of commits to master in tools/my-tool (that are not already in featureA), in reverse-chronological order:

git log --no-merges featureA...master tools/my-tool 

To say it another way:

git log --no-merges source_branch...dest_branch my/firstpath my/secondpath [...] 

To get just the commits you need in chronological order, you need to first reverse the order of the input lines (such as with tail -r or tac), then isolate the column for the commit hash (such as with cut):

git log --format=oneline --no-merges featureA...master tools/my-tool \     | tail -r \     | cut -d " " -f 1 

And to do the whole operation at once, do this:

git cherry-pick $(git log --format=oneline --no-merges featureA...master tools/my-tool | tail -r | cut -d " " -f 1) 

Answer 2

Here is the right way to cherry-pick commits from another branch for one folder:

git format-patch -k --stdout master...featureA -- tools/mytool | git am -3 -k

This will apply the patches to the "tools/mytool" files only, in order.

If you have a merge conflict on any commit, it will pause for you to fix it. git am --continue will resume where it left off.