Question

Is it possible to setup deployment script so that vendors would only update if deps file has changed since the last update?

Answer 1

I struggled with the same problem one week ago and I found the solution.
The file symfony2.rb (at my server located under /var/lib/gems/1.8/gems/capifony-2.1.4/lib) has the following ruby-code at the very end:

case vendors_mode
  when "upgrade" then symfony.vendors.upgrade
  when "install" then symfony.vendors.install
  when "reinstall" then symfony.vendors.reinstall
end

Also at the very top of the same file you can see the default value for vendors_mode:

set :vendors_mode, "reinstall"

Now in my deploy.rb I used the following:

set :vendors_mode, "install"

With this setting vendors are only installed if they don’t exist yet in the target-version of the deps-file!