Question

I installed a new gem needle in my rails 3.1.

It installed properly but when I start my rails using command rails server --debugger

I get the following warnings:

.rvm/gems/ruby-1.9.2-p290/gems/needle-1.3.0/lib/needle/definition-context.rb:36: warning: undefining `initialize' may cause serious problems
.rvm/gems/ruby-1.9.2-p290/gems/needle-1.3.0/lib/needle/definition-context.rb:36: warning: undefining 'object_id' may cause serious problems
.rvm/gems/ruby-1.9.2-p290/gems/needle-1.3.0/lib/needle/definition-context.rb:36: warning: undefining '__send__' may cause serious problems

How can I get rid of it?

Answer 1

The problem is within the needle gem itself. It does this:

public_instance_methods -
[ "instance_eval", "object_id", "__id__", "__send__", "initialize",
  "remove_const", "method_missing", "method", "class", "inspect", "to_s",
  "instance_variables", "block_given?" ]

But in Ruby 1.9, the public_instance_methods method returns objects of the Symbol variety, not String. So what happens is effectively this:

[:__send__, <and other methods>] - ["__send__", <and other methods>]
=> [:__send__, <and other methods>]

When it should be NOT removing those methods in the provided Array.

This indicates to me that the library hasn’t been updated (or at least tested) for Ruby 1.9. I would recommend finding where the code is for this library, forking it and then applying a patch that converts the array to symbols using something like map(&:to_sym) to fix this problem.

But be aware: there may be other cases where these differences between 1.8 and 1.9 are present.