How do you hook up git to emerge through emacsclient?

Question

I previously had the following script in a file called .emacs.d/emerge-for-git:

#!/bin/sh
emacs -Q $*

And In my .gitconfig:

[merge]
  tool = emerge
[mergetool "emerge"]
  path = /home/rovanion/.emacs.d/emerge-for-git

But wishing to improve upon that so that it would connect to the already running emacsclient I ended up with the following lines:

#!/bin/sh
emacsclient -nw  --eval "(emerge-files nil \"$3\" \"$4\" \"${4}.out\")""\")"

But that ended up saving the merged file to source/path/path instead of source/path. So to save myself some grey hairs, and posterity of course, I decided to ask you instead:

How do you hook up git to your emacsclient?

Answer 1

I got a somewhat working solution going. In my .gitconfig I have:

[mergetool "emerge"]
    prompt = false
    cmd = emerge "$LOCAL" "$REMOTE" "$BASE" "$MERGED"
trustExitCode = true

And in .local/bin/emerge

#!/bin/bash
set -e

local=$(readlink -f "$1")
remote=$(readlink -f "$2")
base=$(readlink -f "$3")
merged=$(readlink -f "$4")

emacsclient -nw --eval "(emerge-files-with-ancestor nil \"$local\" \"$remote\" \"$base\" \"$merged\")"

! egrep -q '^(<<<<<<<|=======$|>>>>>>>|####### Ancestor)' "$merged"

The remaining issue is that the emacsclient is not automatically killed when q is pressed.