Adopt Rails style binary?

[skade]

The rails binary does a clever trick to circumvent the bundle exec-problem. If it detects that it is runs in a Rails project, it basically restarts itself by using script/rails and makes sure it runs in the projects environment. See Details here: http://yehudakatz.com/2011/05/30/gem-versioning-and-bundler-doing-it-right/

Do we want to adopt a similar technique?

[DAddYE]

We use the same way without needs to have a script inside, basically when we load boot.rb we just check Gemfile and deps. Btw thanks for the suggestion!

[skade]

The linked post exactly elaborates why Rails does not do this, as it is not enough. The problem can be easily seen with Padrino as well.

Using the following Gemfile:

# Padrino
gem 'padrino', "0.9.28"

And:

padrino --version #=> Padrino v. 0.9.29

You get the following:

$ padrino start
[ skade Florian-Gilchers-MacBook-Pro ~/Code/padrino-binary/padrino-test ] padrino start
/Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/runtime.rb:31:in `block in setup': You have already activated padrino-core 0.9.29, but your Gemfile requires padrino-core 0.9.28. Consider using bundle exec. (Gem::LoadError)
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `block in each'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/runtime.rb:17:in `setup'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler.rb:107:in `setup'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/bundler-1.0.10/lib/bundler/setup.rb:6:in `<top (required)>'
    from <internal:lib/rubygems/custom_require>:33:in `require'
    from <internal:lib/rubygems/custom_require>:33:in `rescue in require'
    from <internal:lib/rubygems/custom_require>:29:in `require'
    from /Users/skade/Code/padrino-binary/padrino-test/config/boot.rb:7:in `<top (required)>'
    from <internal:lib/rubygems/custom_require>:29:in `require'
    from <internal:lib/rubygems/custom_require>:29:in `require'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/padrino-core-0.9.29/lib/padrino-core/cli/base.rb:23:in `start'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/task.rb:22:in `run'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/invocation.rb:118:in `invoke_task'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor.rb:263:in `dispatch'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/base.rb:389:in `start'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/gems/padrino-core-0.9.29/bin/padrino:8:in `<top (required)>'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/bin/padrino:19:in `load'
    from /Users/skade/.rvm/gems/ruby-1.9.2-p180/bin/padrino:19:in `<main>'

Thats a big hassle for people supporting projects in more than one version of padrino without resorting to .rvmrc-mangling. So some form of self-executing-magic is needed. The question is whether we really want a script/rails-style binary or detect some other magic marker, components for example.