DBI Row / delegate behavior between ruby 1.8.7 and 2.1

Question

I execute the following code in ruby 1.8.7 to read rows from my database:

require 'dbi'
db_conn_handle = DBI.connect("DBI:Mysql:host=localhost;database=mydb;port=3306", "root")
sth = db_conn_handle.prepare("select accounts.id, accounts.name from accounts;")
sth.execute
info = sth.to_a
puts "Info: #{info[0].class}"
info.each do |x, y|
  puts "#{x} ... #{y}"
end

From the output it is clear that info[0].class is DBI::Row. This code works perfectly when executed with ruby 1.8.7 (rails 3.2.17)

When I try executing it in ruby 2.1.5 / rails 3.2.17, it gives the following error:

/home/rjain/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/delegate.rb:392:in `__getobj__': not delegated (ArgumentError)
    from /home/rjain/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/delegate.rb:341:in `block in delegating_block'
    from /home/rjain/mac/query.rb:7:in `each'
    from /home/rjain/mac/query.rb:7:in `<top (required)>'
    from /home/rjain/.rvm/gems/ruby-2.1.5/gems/railties-3.2.17/lib/rails/commands/runner.rb:52:in `eval'
    from /home/rjain/.rvm/gems/ruby-2.1.5/gems/railties-3.2.17/lib/rails/commands/runner.rb:52:in `<top (required)>'
    from /home/rjain/.rvm/gems/ruby-2.1.5/gems/railties-3.2.17/lib/rails/commands.rb:64:in `require'
    from /home/rjain/.rvm/gems/ruby-2.1.5/gems/railties-3.2.17/lib/rails/commands.rb:64:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

The file /home/rjain/mac/query.rb is pasted above. I want to understand whats the difference between ruby 2.1 and 1.8 that causes this issue. What is the fix for this problem?

Answer 1

Ran into the same issue, tracked down the problem.

Find lib/dbi/row.rb in the gem directory. Line 212 or thereabouts should read

        if RUBY_VERSION =~ /^1\.9/

Edit it to be

        if RUBY_VERSION =~ /^1\.9/ || RUBY_VERSION =~ /^2/