Diff should compare missing fields by default

Author: Adam Gardiner

lib/csv-diff/csv_diff.rb

@@ -86,7 +86,7 @@ def initialize(left, right, options = {})
         @right = right.is_a?(CSVSource) ? right : CSVSource.new(right, options)
         raise "No field names found in right (to) source" unless @right.field_names && @right.field_names.size > 0
         @warnings = []
-        @diff_fields = get_diff_fields(@left.field_names, @right.field_names, options[:ignore_fields])
+        @diff_fields = get_diff_fields(@left.field_names, @right.field_names, options)
         @key_fields = @left.key_fields.map{ |kf| @diff_fields[kf] }
         diff(options)
     end
@@ -137,15 +137,21 @@ def diff_warnings
 
     # Given two sets of field names, determines the common set of fields present
     # in both, on which members can be diffed.
-    def get_diff_fields(left_fields, right_fields, ignore_fields)
+    def get_diff_fields(left_fields, right_fields, options)
+        ignore_fields = (options[:ignore_fields] || []).map do |f|
+            f.is_a?(Fixnum) ? right_fields[f] : f
+        end
         diff_fields = []
-        right_fields.each_with_index do |fld, i|
-            if left_fields.include?(fld)
-                diff_fields << fld unless ignore_fields && (ignore_fields.include?(fld) ||
-                                                            ignore_fields.include?(i))
-            else
-                @warnings << "Field '#{fld}' is missing from the left (from) file, and won't be diffed"
+        if options[:diff_common_fields_only]
+            right_fields.each_with_index do |fld, i|
+                if left_fields.include?(fld)
+                    diff_fields << fld unless ignore_fields.include?(fld)
+                else
+                    @warnings << "Field '#{fld}' is missing from the left (from) file, and won't be diffed"
+                end
             end
+        else
+            diff_fields = (right_fields + left_fields).uniq.reject{ |fld| ignore_fields.include?(fld) }
         end
         diff_fields
     end