Git Dig (find deleted files whose content matches a regex)

git_dig.rb

#!/usr/bin/env ruby

require 'optparse'
require 'open3'

def files_with_search_query(sha, search_query)
  `git show --format="" --name-only #{sha} -i --pickaxe-regex -S #{search_query}`.split("\n")
end

def grep_over_file(sha, file, search_query)
  git_show_cmd = "git show --format='' -p #{sha} -- '#{file}'"
  grep_cmd = "grep -i --color=always -E #{search_query}"
  `#{git_show_cmd} | #{grep_cmd}`
end

def git_pickaxe_search(search_query, options, &block)
  git_log_cmd = "git log --no-merges --format=%h"
  git_log_cmd += " --after=\"#{options[:after]}\"" if options[:after]
  git_log_cmd += " --before=\"#{options[:before]}\"" if options[:before]
  git_log_cmd += " -i --pickaxe-regex -S #{search_query}"

  Open3.popen3(git_log_cmd) do |stdin, stdout, stderr, thread|
    yield(stdout)
  end
end

def git_commit_info(sha)
  `git show --no-patch #{sha}`
end

def find_root_dir
  current_dir = Dir.pwd

  until Dir.exist?([current_dir, ".git"].join(File::SEPARATOR)) do
    parent_dir = File.dirname(current_dir)

    if parent_dir == current_dir
      puts "No .git repo found in path (or parent paths)."
      exit
    end

    current_dir = parent_dir
  end

  current_dir
end

# Handle options
options = {}
OptionParser.new do |opts|
  opts.banner = "Usage: git-dig [options] [regex query]"

  opts.on("--after=DATE", "Only searches commits more recent than the specific date.") do |v|
    options[:after] = v
  end

  opts.on("--before=DATE", "Only searches commits older recent than the specific date.") do |v|
    options[:before] = v
  end

  opts.on("-h", "--help", "Prints this help") do
    puts opts
    exit
  end
end.parse!

# Get search query
search_query = "\"#{ARGV.first}\""
if search_query == '""' # empty search as it would just be a pair of quotes
  puts "You need to pass a search term as input."
  exit
end

puts "Searching for any commits with any 'additions/removals'"
puts "  Matching regex: #{search_query}"
if options[:after] || options[:before]
  puts "  With search options: #{options}"
end
puts ""

# Get SHAs of all commits which had some 'addition/removal' of the search term
git_pickaxe_search(search_query, options) do |stdout|
  while line = stdout.gets
    exit if line.nil?

    sha = line.strip

    puts git_commit_info(sha)
    puts ""

    # Print diff of files which have search term
    files_with_search_query(sha, search_query).each do |file|
      puts "FILE -> #{file}"
      puts grep_over_file(sha, file, search_query)
      puts ""
    end

    puts "-"*80
    puts ""
  end
end

Very useful, thank you!