gistfile1.txt

#!/bin/env ruby

pwd = Dir.pwd

puts "Working out of directory #{pwd}"

upstream_dir=File.join(pwd, 'upstream')
downstream_dir=File.join(pwd, 'downstream')

def system_cmd (cmd, print_output=false)
  puts "Running cmd: #{cmd}"
  output = `#{cmd}`.split("\n")
  if print_output
    puts output
  else
    #puts output
  end
  #raise(StandardError, "Cmd #{cmd} failed") unless $?.success?
  [output, $?.success?]
end

def get_rev_list(dir, opts='--no-merges')
  rev_list=[]
  Dir.chdir(dir) do
    rev_list=`git rev-list #{opts} HEAD`.split("\n")
  end
  rev_list
end

def checkout(dir, commit, opts='')
  puts "Checking out upstream: #{commit}"
  Dir.chdir(dir) do
    output=`git checkout #{commit} #{opts}`
    puts output
  end
end

# start from origin/master
checkout(downstream_dir, 'origin/master')
checkout(upstream_dir, 'origin/master')

# get all revisions
rev_list_down=get_rev_list(downstream_dir)
rev_list_up=get_rev_list(upstream_dir)
puts "UP revs count #{rev_list_up.size}"


# start with first commit from downstream
#rev_list_down.reverse.each do |ref|
output_size={}
ref = rev_list_down.reverse.first
  checkout(downstream_dir, ref)
  rev_list_up.each do |ref2|
    checkout(upstream_dir, ref2)
    t out = system_cmd('diff -r --exclude=.svn --exclude=.git upstream downstream')
    if out[1]
      puts "Upstream #{ref} matches downstream #{ref2}"
      exit 0
    else
      output_size[out[0].size] ||= {}
      output_size[out[0].size]["#{ref}_#{ref2}"] = out[0]
    end
  end
#end

puts "Could not find any common anscestor"
smallest = output_size.keys.sort.first
puts smallest
puts output_size[smallest].size
puts output_size[smallest].values.first.join("\n")
#puts output_size[output_size.keys.sort.first].inspect