Per-branch Gemfile.lock

post-checkout.sh

#!/bin/bash

if [ "$3" = 1 ]; then
  old_branch="`git name-rev --name-only --no-undefined "$1" | cut -d'~' -f1`"
  new_branch="`git name-rev --name-only --no-undefined "$2" | cut -d'~' -f1`"

  if [ "$old_branch" != "$new_branch" ]; then
    mv -f "Gemfile.lock" ".Gemfile/lock.$old_branch"
    if [ -f ".Gemfile/lock.$new_branch" ]; then
      mv -f ".Gemfile/lock.$new_branch" "Gemfile.lock"
    else
      closest_match="$old_branch"
      cp -f ".Gemfile/lock.$closest_match" "Gemfile.lock"
    fi
  fi
fi