Problems with heroku deployment, DateTime and strftime

Question

I'm having trouble to deploy my rails application to Heroku. I did it just as normally, but this time I got these errors on the console.

I wonder how they can appear, because I don't even have gsub! used in here.

In my normal production environment it worked just fine, so what did I forget to think about in this case?

Thanks for your help!

The Error prompts: (by the way, the database content isn't nil or something like that)

Started GET "/tournaments" for XXX at 2012-11-29 17:14:18 +0000
Processing by TournamentsController#index as HTML
  Rendered tournaments/index.html.erb within layouts/application (74.9ms)
Completed 500 Internal Server Error in 193ms

    31:     <td><%= raw tournament.address.split(", ").join("<br />") %></td>
    33:     <td><%= DateTime.parse(tournament.date).strftime("%H:%M") %></td>
ActionView::Template::Error (undefined method `gsub!' for 2012-12-08 15:00:00 UTC:Time):
    30:     <td><%= tournament.place %> von <%= tournament.participants %></td>
    35:     <td><%= link_to 'Show', tournament %></td>
  app/views/tournaments/index.html.erb:32:in `block in _app_views_tournaments_index_html_erb___1016767371206226983_23066580'
  app/views/tournaments/index.html.erb:26:in `each'
  app/views/tournaments/index.html.erb:26:in `_app_views_tournaments_index_html_erb___1016767371206226983_23066580'
    29:     <td><%= tournament.user.name %></td>

  app/controllers/tournaments_controller.rb:11:in `index'
    32:     <td><%= DateTime.parse(tournament.date).strftime("%d.%m.%Y") %></td>
    34:     <td><%= tournament.kind %></td>

Answer 1

It looks like the object returned by tournament.date is of type Time, where as DateTime.parse expects a string. The underlying implementation of the parse method does a gsub! on the argument passed. Hence the error.

You have two solutions :

1. If you always get a Time object from tournament.date then you can use tournament.date.to_datetime (Although I don't think you actually need a DateTime object. You can use the Time object for the strftime)

2. If you aren't guaranteed a Time object then pass the stringified object to parse like this DateTime.parse(tournament.date.to_s)

P.S : I do not know how this code worked for you on your local machine. Could be because of different ruby versions in the two setups. My answer is based on MRI 1.9.2.