Cucumber::Ast::Table: How to correctly handle "inner" rows with :surplus_row?

Question

I'd like to compare a Cucumber::Ast::Table of (at least) expected values with an array containing my actual values, but I want to ignore additional rows. For this, I thought I could use the diff! method with :surplus_row => false.

This works as expected (Cucumber reports success):

table (Cucumber::Ast::Table):

  |id|name |
  |1 |one  |
  |2 |two  |

@actual:
  |id|name |
  |1 |one  |
  |2 |two  |
  |3 |three|

But this does not (I get Cucumber::Ast::Table::Different ):

table (Cucumber::Ast::Table):

  |id|name |
  |2 |two  |

@actual:
  |id|name |
  |1 |one  |
  |2 |two  |
  |3 |three|

So it seems Cucumber is reporting a false positive if my @actual contains only "inner" rows. Is this a bug in Cucumber? Or am I making some stupid mistake?

CODE

table.feature:

Feature: Comparing Cucumber tables

Scenario: Comparing with a table with additional rows
Given I have a table with three rows and two columns
 When I compare this table with an additional row and the same columns
 Then I should get at least these rows
    |id|name |
    |2 |two  |

table_steps.rb:

Given /^I have a table with three rows and two columns$/ do
  @actual = [ { "id" => "1", "name" => "one" },
              { "id" => "2", "name" => "two"},
              { "id" => "3", "name" => "three" } ]
end

When /^I compare this table with an additional row and the same columns$/ do
  # no-op
end

Then /^I should get at least these rows$/ do |table|
  table.diff!(@actual, { :surplus_row => false } )
end

Cucumber version 1.2.1

Answer 1

Turns out it was a bug in the old cucumber version I was using. Upgrading from 1.2.1 to 1.3.10 fixed the issue.

See Cucumber Github Issue for details regarding the bug.