Rails production environment breaks with cycle

Question

Have a rails app (3.0.9) using HAML, local development server runs fine. But when I run rails s -e production, my page gives this error:

NoMethodError: undefined method `+@' for #<String:0x00000006331098>

The error says it is on this line (from the view, written in HAML):

%tr{:class=> cycle("even","odd")}

I'm not finding anything about why this is happening. Please help.

Answer 1

Does the cycle method do any sort of string concatenation?

I encountered this error recently during a code review.

The code was something like this:

anObject.instance_method +string_var

The instance_method was returning a string which was to be appended with the string value present in variable string_var.

Changing the code to this worked

anObject.instance_method + string_var # Note the space after the +

Without space the unary + method is invoked on the string_var, but no unary + method is defined on the String class. Hence the exception.

Note that the unary + method is defined as def +@, hence the exception message says "Method +@ not found".

This gist makes it clear : https://gist.github.com/1145457

Anyways, in your case, the method cycle (do not know whether it is defined by you or is part of a gem) is probably doing some string concatenation without proper spacing OR the exception backtrace is not pointing to the right line of code.

Hope this helps.