Ruby

following code behaves differently between ruby 2.2.2/trunk and 2.1.5.

require 'csv' converter = lambda { |field| field.nil? } p CSV.parse_line('nil,', converters: converter) 

$ ruby -v ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin14.0] $ ruby csv.rb [false, true] 

$ ruby -v ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-darwin14] $ ruby csv.rb [false, nil] 

CSV header conversion changed at r45497 but it also affects field conversion.
https://github.com/ruby/ruby/pull/575

I attached a patch to revert the field conversion behavior to >= 2.1.

diff --git lib/csv.rb lib/csv.rb index 54b820d..2edaf5a 100644 --- lib/csv.rb +++ lib/csv.rb @@ -2188,7 +2188,7 @@ def convert_fields(fields, headers = false)   fields.map.with_index do |field, index| converters.each do |converter| - break if field.nil? + break if headers && field.nil?  field = if converter.arity == 1 # straight field converter converter[field] else # FieldInfo converter diff --git test/csv/test_data_converters.rb test/csv/test_data_converters.rb index 89b6dd1..3a6f46f 100755 --- test/csv/test_data_converters.rb +++ test/csv/test_data_converters.rb @@ -175,6 +175,15 @@ def test_convert_with_custom_code_using_field_info_header @parser.shift.fields ) end  + def test_custom_converter_with_blank_field + converter = lambda { |field| field.nil? } + row = nil + assert_nothing_raised(Exception) do + row = CSV.parse_line('nil,', converters: converter) + end + assert_equal([false, true], row); + end +  def test_shortcut_interface assert_equal( ["Numbers", ":integer", 1, ":float", 3.015], CSV.parse_line(@data, converters: :numeric) )