Ruby subversion pre-commit hook to prevent conflicting Rails migrations

conorh (Conor Hunt) — Thu, 26 Oct 2006 18:19:51 GMT

This is a subversion pre-commit hook that prevents a Ruby on Rails migration being committed that has the same version as an existing migration. To install you place this in a file called pre-commit in the hooks directory of your subversion repository. You can read about hooks here: http://svnbook.red-bean.com/en/1.0/ch05s02.html



#!/usr/bin/env ruby



repo_path = ARGV[0]

transaction = ARGV[1]

svnlook = '/usr/bin/svnlook'



commit_dirs_changed = `#{svnlook} dirs-changed #{repo_path} -t #{transaction}`

commit_changed = `#{svnlook} changed #{repo_path} -t #{transaction}`

#commit_author = `#{svnlook} author #{repo_path} -t #{transaction}`.chop

commit_log = `#{svnlook} log #{repo_path} -t #{transaction}`

#commit_diff = `#{svnlook} diff #{repo_path} -t #{transaction}`

#commit_date = `#{svnlook} date #{repo_path} -t #{transaction}`



# ******* Migration check ********

# if this is a migration then check that there is not already a migration with the same version number in the repository

files = commit_changed.split(/\n/)

current_migrations = nil

for file in files

  if(file =~ /A\s*(.*?\/migrate\/)(\d+)(.*)/)

    migration_path = $1

    migration_version = $2

    

    if(current_migrations == nil)

      current_migrations = {}

      migration_files = `#{svnlook} tree #{repo_path} #{migration_path}`

      for migration in migration_files

        current_migrations[$1] = true if(migration =~ /\s*(\d+)_(.*)/)

      end

    end

    

    if(current_migrations[migration_version])

     STDERR.puts("The is a pre-existing migration with version #{migration_version} in #{migration_path}")

     exit(1)

    end

  end

end

Example of Detecting Subclasses

jimweirich (Jim Weirich) — Wed, 13 Apr 2005 11:03:57 GMT

class A
def A.inherited(clazz)
puts "Hey, #{clazz} is subclassing me"
end
end

class B < A; end

Produces:

$ ruby x.rb
Hey, B is subclassing me

DZone Snippets: hook code

Ruby subversion pre-commit hook to prevent conflicting Rails migrations

Example of Detecting Subclasses