Merge pull request #577 from Shopify/table-row-blank-string-collection

Fix exception from using an empty string for the table row collection.

lib/liquid/tags/for.rb

@@ -76,9 +76,6 @@ module Liquid
       collection = context.evaluate(@collection_name)
       collection = collection.to_a if collection.is_a?(Range)
 
-      # Maintains Ruby 1.8.7 String#each behaviour on 1.9
-      return render_else(context) unless iterable?(collection)
-
       from = if @from == :continue
         for_offsets[@name].to_i
       else
@@ -189,10 +186,6 @@ module Liquid
     def render_else(context)
       @else_block ? @else_block.render(context) : ''.freeze
     end
-
-    def iterable?(collection)
-      collection.respond_to?(:each) || Utils.non_blank_string?(collection)
-    end
   end
 
   Template.register_tag('for'.freeze, For)

lib/liquid/utils.rb

@@ -8,16 +8,15 @@ module Liquid
       end
     end
 
-    def self.non_blank_string?(collection)
-      collection.is_a?(String) && collection != ''.freeze
-    end
-
     def self.slice_collection_using_each(collection, from, to)
       segments = []
       index = 0
 
       # Maintains Ruby 1.8.7 String#each behaviour on 1.9
-      return [collection] if non_blank_string?(collection)
+      if collection.is_a?(String)
+        return collection.empty? ? [] : [collection]
+      end
+      return [] unless collection.respond_to?(:each)
 
       collection.each do |item|
         if to && to <= index

test/integration/tags/table_row_test.rb

@@ -57,4 +57,8 @@ class TableRowTest < Minitest::Test
       '{% tablerow n in numbers cols:3 offset:1 limit:6%} {{n}} {% endtablerow %}',
       'numbers' => [0, 1, 2, 3, 4, 5, 6, 7])
   end
+
+  def test_blank_string_not_iterable
+    assert_template_result("<tr class=\"row1\">\n</tr>\n", "{% tablerow char in characters cols:3 %}I WILL NOT BE OUTPUT{% endtablerow %}", 'characters' => '')
+  end
 end