Prevent Range usage in templates from blowing up

Make Template.tags loop-able

lib/liquid/extensions.rb

@@ -25,6 +25,12 @@ class Numeric # :nodoc:
   end
 end
 
+class Range # :nodoc:
+  def to_liquid
+    self
+  end
+end
+
 class Time # :nodoc:
   def to_liquid
     self

lib/liquid/standardfilters.rb

@@ -289,6 +289,12 @@ module Liquid
       array.last if array.respond_to?(:last)
     end
 
+    # absolute value
+    def abs(input)
+      result = Utils.to_number(input).abs
+      result.is_a?(BigDecimal) ? result.to_f : result
+    end
+
     # addition
     def plus(input, operand)
       apply_operation(input, operand, :+)

lib/liquid/tags/raw.rb

@@ -6,9 +6,7 @@ module Liquid
     def initialize(tag_name, markup, parse_context)
       super
 
-      unless markup =~ Syntax
-        raise SyntaxError.new(parse_context.locale.t("errors.syntax.tag_unexpected_args".freeze, tag: tag_name))
-      end
+      ensure_valid_markup(tag_name, markup, parse_context)
     end
 
     def parse(tokens)
@@ -35,6 +33,14 @@ module Liquid
     def blank?
       @body.empty?
     end
+
+    protected
+
+    def ensure_valid_markup(tag_name, markup, parse_context)
+      unless markup =~ Syntax
+        raise SyntaxError.new(parse_context.locale.t("errors.syntax.tag_unexpected_args".freeze, tag: tag_name))
+      end
+    end
   end
 
   Template.register_tag('raw'.freeze, Raw)

lib/liquid/template.rb

@@ -19,6 +19,8 @@ module Liquid
     @@file_system = BlankFileSystem.new
 
     class TagRegistry
+      include Enumerable
+
       def initialize
         @tags = {}
         @cache = {}
@@ -41,6 +43,10 @@ module Liquid
         @cache.delete(tag_name)
       end
 
+      def each(&block)
+        @tags.each(&block)
+      end
+
       private
 
       def lookup_class(name)

test/integration/standard_filter_test.rb

@@ -385,6 +385,19 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result "5", "{{ price | minus:'2' }}", 'price' => NumberLikeThing.new(7)
   end
 
+  def test_abs
+    assert_template_result "17", "{{ 17 | abs }}"
+    assert_template_result "17", "{{ -17 | abs }}"
+    assert_template_result "17", "{{ '17' | abs }}"
+    assert_template_result "17", "{{ '-17' | abs }}"
+    assert_template_result "0", "{{ 0 | abs }}"
+    assert_template_result "0", "{{ '0' | abs }}"
+    assert_template_result "17.42", "{{ 17.42 | abs }}"
+    assert_template_result "17.42", "{{ -17.42 | abs }}"
+    assert_template_result "17.42", "{{ '17.42' | abs }}"
+    assert_template_result "17.42", "{{ '-17.42' | abs }}"
+  end
+
   def test_times
     assert_template_result "12", "{{ 3 | times:4 }}"
     assert_template_result "0", "{{ 'foo' | times:4 }}"

test/integration/template_test.rb

@@ -306,4 +306,14 @@ class TemplateTest < Minitest::Test
       t.render!({ 'x' => 'foo' }, { strict_filters: true })
     end
   end
+
+  def test_using_range_literal_works_as_expected
+    t = Template.parse("{% assign foo = (x..y) %}{{ foo }}")
+    result = t.render({ 'x' => 1, 'y' => 5 })
+    assert_equal '1..5', result
+
+    t = Template.parse("{% assign nums = (x..y) %}{% for num in nums %}{{ num }}{% endfor %}")
+    result = t.render({ 'x' => 1, 'y' => 5 })
+    assert_equal '12345', result
+  end
 end

test/unit/block_unit_test.rb

@@ -46,6 +46,8 @@ class BlockUnitTest < Minitest::Test
   def test_with_custom_tag
     Liquid::Template.register_tag("testtag", Block)
     assert Liquid::Template.parse("{% testtag %} {% endtesttag %}")
+  ensure
+    Liquid::Template.tags.delete('testtag')
   end
 
   private

test/unit/template_unit_test.rb

@@ -67,4 +67,12 @@ class TemplateUnitTest < Minitest::Test
     Template.tags.delete('fake')
     assert_nil Template.tags['fake']
   end
+
+  def test_tags_can_be_looped_over
+    Template.register_tag('fake', FakeTag)
+    result = Template.tags.map { |name, klass| [name, klass] }
+    assert result.include?(["fake", "TemplateUnitTest::FakeTag"])
+  ensure
+    Template.tags.delete('fake')
+  end
 end