Using GitKraken I want to compare 2 branches from 2 different repositories, however I can only see how to compare branches within the same repository.
Both of these repositories are pulled locally.
On
You can add the object databases as alternate sources and compare the tips by id. To do it temporarily, without affecting the originals at all, do it in a scratch clone:
git clone -s --bare /path/to/repo/a `mktemp -d`; cd $_
echo >>objects/info/alternates \
$(cd /path/to/repo/b; cd $(git rev-parse --git-path objects); pwd)
git diff \
$(git -C /path/to/repo/a rev-parse abranch) \
$(git -C /path/to/repo/b rev-parse anotherbranch)
or if you want the refs appearing in your scratch clone you can remap the prefixes like
git fetch /path/to/repo/a refs/heads/*:refs/heads/repoa/*
git fetch /path/to/repo/b refs/heads/*:refs/heads/repob/*
which will copy nothing since all the objects are already accessible, and you can then
git diff repoa/main repob/feature
or whatever.
Meldwas what I used for this and it works fantastically.http://meldmerge.org/