Compare old and new versions of force-pushed GitHub pull request

Question

Frequently, my colleagues will make some changes to an open pull request, rebase their local branch against the base branch - often squashing their changes into previous commits

Answer 1

The following works, but is inefficient for large repos because the whole repo worktrees are downloaded:

repo=rossant/awesome-math
a=61e250
b=2b53ad
tmp=$(mktemp -d -p /tmp)
mkdir -p $tmp/{a,b}
curl -SL https://github.com/$repo/archive/$a.tar.gz | tar xz --strip-components=1 -C $tmp/a
curl -SL https://github.com/$repo/archive/$b.tar.gz | tar xz --strip-components=1 -C $tmp/b
git diff --no-index $tmp/{a,b}
rm -r $tmp

This could be much simpler and leaner if Github would allow git fetching revs by their SHA1, but that's not the case yet.