Pequeño script para detectar quien require a iconv robado de acá http://stackoverflow.com/questions/7957888/tracing-dependency-loading-in-rails

horrible_patch.rb

# override Kernel#require to intercept stderr messages on require
# and raise a custom error if we find one mentioning 'iconv'
require "stringio"

class RequireError < StandardError
end

module Kernel

  alias   :the_original_require require
  private :the_original_require

  def capture_stderr
    previous_stderr = $stderr
    $stderr         = StringIO.new
    yield
    $stderr.string
  ensure
    # Restore the previous value of stderr (typically equal to STDERR).
    $stderr = previous_stderr
  end

  def require name
    captured_output = capture_stderr { the_original_require(name) }
    raise RequireError, 'iconv requirement found' if captured_output =~ /iconv/
  end

end

require 'bundler'

# load the list of Bundler requirements from the Gemfile
required_libraries = Bundler.definition.dependencies.map(&:name)

# loop through and require each, ignoring all errors other than
# our custom error

required_libraries.each do |requirement|
  begin
    require requirement
  rescue Exception => e
    raise e if e.class == RequireError
  end
end