A Day In The Lyf

…the lyf so short, the craft so longe to lerne

Auto-merging fixes

Paul Gross recently blogged about a rake task to automatically merge changes to the trunk if the change was made in a branch. This seemed like a useful feature, even though we don’t use rake.

Fixing productions bugs and merging is no fun, but why not take some of the pain out of the process? Depending on the developer and their mood, we either fix the bug in the trunk and merge to the branch, or fix it it the branch and merge to the trunk. Where it really gets ugly is when we have to merge two release branches back, because we make our release branch a few days before actually pushing it to production. Any urgent bug fix requiring a merge during that time has to be merged both to the new release branch as well as to the release branch currently in production.

Using Paul’s code as a base, I wrote automerge.rb, which, by default, either merges to the trunk (if you’re in a branch), or merges to the latest release branch (if you’re in the trunk). Alternatively, you can pass a release number, and automerge.rb will merge to that release branch. In all cases, you have to have the working copy checked out on your machine, and, if you’re on Windows, you need to make sure to put patch in your path.

The script assumes that your directory structure looks something like the following:

/trunk
 /branches
   /Release-2.8
   /Release-2.9

The Release-major-minor format is just our branch naming standard; it’s easy to change.

if !ARGV[0].nil?
  dest_dir = "branches/Release-#{ARGV[0]}"
  replace_pattern = /(trunk|branches).*$/i
elsif %x[svn info].include? "branches"
  dest_dir = "trunk"
  replace_pattern = /branches.*$/i
elsif %x[svn info].include? "trunk"
  pattern = /^Release-(\d+).(\d+)\/$/

  branches = %x[svn list http://devtools01:8080/svn/lazarus/branches]
  releases = branches.split.find_all {|branch| branch =~ pattern}

  # sort them in reverse order by major, minor
  releases.sort! do |first, second|
    first_major, first_minor = pattern.match(first)[1..2]
    second_major, second_minor = pattern.match(second)[1..2]

    if first_major != second_major
      second_major.to_i <=> first_major.to_i
    else
      second_minor.to_i <=> first_minor.to_i
    end
  end

  dest_dir = "branches/#{releases[0]}"
  replace_pattern = /trunk/
end

puts "Merging changes into #{dest_dir}.  Don't forget to check these in."
dest_path = Dir.pwd.gsub(replace_pattern, dest_dir)
puts dest_path
system "svn diff | patch -p0 -d #{dest_path}"

The only tricky part here is figuring out the latest release branch, which is done by using the svn list command followed by a custom sort.

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Written by Brandon Byars

October 22, 2007 at 8:06 pm

Posted in Configuration Management, Ruby

Tagged with ,

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