合并来自另一个存储库的文件夹更改

Question

We have a git repository ProjA with a plugin stored in /plugins/foo . After this project was completed, a second repository ProjB was started. Somewhere along the line foo was added to the repo like so

cp ../ProjA/plugins/foo plugins/foo
git add .
git commit -m "Added Foo Plugin"

followed immediately by

git mv plugins/foo plugins/foobar
git commit -m "Fixed naming conflict with Foo"

Then a bunch of work was done.

How do I merge all the changes (and more importantly history) to ProjB/plugins/foobar into ProjA/plugins/foo without any of the other changes in ProjB/ ?
I've tried creating a subtree and merge it in but all the changes were in / and there were no common ancestors to merge with.
Then I tried using git format-patch but I couldn't work out how to make it only apply to a subdirectory.
My best guess is to somehow combine the two actions but I don't know how to deal with the paths.

Answer 1

I managed to sort out the paths using --src-prefix and --dst-prefix on git format-patch .
There were a few problems involving merges that I had to sort out manually during the 200+ commits imported, but other than that it seems to have worked.

My end workflow was something like this:

cd ProjB
git subtree split --prefix=plugins --branch=plugins-only
mkdir ../ProjBPlugins
cd ../ProjBPlugins
git init .
git pull ../ProjB plugins-only
git format-patch --stdout --src-prefix=a/plugins/ --dst-prefix=b/plugins/ e2f0732f92078a83fd210d415b659b41817a865f > foo.patch
cp foo.patch ../ProjA/
cd ../ProjA
git am foo.patch