allow incomplete tags inside a comment tag

Co-authored-by: Peter Zhu <peter@peterzhu.ca>

lib/liquid/block_body.rb

@@ -6,6 +6,7 @@ module Liquid
   class BlockBody
     LiquidTagToken      = /\A\s*(#{TagName})\s*(.*?)\z/o
     FullToken           = /\A#{TagStart}#{WhitespaceControl}?(\s*)(#{TagName})(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
+    FullTokenPossiblyInvalid = /\A(.*)#{TagStart}#{WhitespaceControl}?\s*(\w+)\s*(.*)?#{WhitespaceControl}?#{TagEnd}\z/om
     ContentOfVariable   = /\A#{VariableStart}#{WhitespaceControl}?(.*?)#{WhitespaceControl}?#{VariableEnd}\z/om
     WhitespaceOrNothing = /\A\s*\z/
     TAGSTART            = "{%"

lib/liquid/tags/comment.rb

@@ -41,22 +41,18 @@ module Liquid
         # The children tag doesn't require to be a valid Liquid except the comment and raw tag.
         # The child comment and raw tag must be closed.
         while (token = tokens.send(:shift))
-          tag_name_match = BlockBody::FullToken.match(token)
+          tag_name_match = BlockBody::FullTokenPossiblyInvalid.match(token)
 
           next if tag_name_match.nil?
 
           tag_name = tag_name_match[2]
 
-          if tag_name == "raw"
+          case tag_name
-            # raw tags are required to be closed
+          when "raw"
             parse_raw_tag_body(tokens)
-            next
+          when "comment"
-          end
-
-          if tag_name_match[2] == "comment"
             comment_tag_depth += 1
-            next
+          when "endcomment"
-          elsif tag_name_match[2] == "endcomment"
             comment_tag_depth -= 1
 
             return false if comment_tag_depth.zero?
@@ -73,7 +69,7 @@ module Liquid
 
     def parse_raw_tag_body(tokens)
       while (token = tokens.send(:shift))
-        return if token =~ Raw::FullTokenPossiblyInvalid && "endraw" == Regexp.last_match(2)
+        return if token =~ BlockBody::FullTokenPossiblyInvalid && "endraw" == Regexp.last_match(2)
       end
 
       raise_tag_never_closed("raw")

lib/liquid/tags/raw.rb

@@ -14,7 +14,6 @@ module Liquid
   # @liquid_syntax_keyword expression The expression to be output without being rendered.
   class Raw < Block
     Syntax = /\A\s*\z/
-    FullTokenPossiblyInvalid = /\A(.*)#{TagStart}#{WhitespaceControl}?\s*(\w+)\s*(.*)?#{WhitespaceControl}?#{TagEnd}\z/om
 
     def initialize(tag_name, markup, parse_context)
       super
@@ -25,7 +24,7 @@ module Liquid
     def parse(tokens)
       @body = +''
       while (token = tokens.shift)
-        if token =~ FullTokenPossiblyInvalid && block_delimiter == Regexp.last_match(2)
+        if token =~ BlockBody::FullTokenPossiblyInvalid && block_delimiter == Regexp.last_match(2)
           parse_context.trim_whitespace = (token[-3] == WhitespaceControl)
           @body << Regexp.last_match(1) if Regexp.last_match(1) != ""
           return

test/unit/tags/comment_tag_unit_test.rb

@@ -4,7 +4,7 @@ require 'test_helper'
 
 class CommentTagUnitTest < Minitest::Test
   def test_does_not_parse_nodes_inside_a_comment
-    template = Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+    assert_template_result("", <<~LIQUID.chomp)
       {% comment %}
         {% if true %}
         {% if ... %}
@@ -16,12 +16,31 @@ class CommentTagUnitTest < Minitest::Test
         {% endcase %}
       {% endcomment %}
     LIQUID
+  end
 
-    assert_equal("", template.render)
+  def test_allows_incomplete_tags_inside_a_comment
+    assert_template_result("", <<~LIQUID.chomp)
+      {% comment %}
+        {% assign foo = "1"
+      {% endcomment %}
+    LIQUID
+
+    assert_template_result("", <<~LIQUID.chomp)
+      {% comment %}
+        {% comment %}
+          {% invalid
+        {% endcomment %}
+      {% endcomment %}
+    LIQUID
+
+    assert_template_result("", <<~LIQUID.chomp)
+      {% comment %}
+      {% {{ {%- endcomment %}
+    LIQUID
   end
 
   def test_child_comment_tags_need_to_be_closed
-    template = Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+    assert_template_result("", <<~LIQUID.chomp)
       {% comment %}
         {% comment %}
           {% comment %}{%    endcomment     %}
@@ -29,10 +48,8 @@ class CommentTagUnitTest < Minitest::Test
       {% endcomment %}
     LIQUID
 
-    assert_equal("", template.render)
-
     assert_raises(Liquid::SyntaxError) do
-      Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+      assert_template_result("", <<~LIQUID.chomp)
         {% comment %}
           {% comment %}
             {% comment %}
@@ -43,7 +60,7 @@ class CommentTagUnitTest < Minitest::Test
   end
 
   def test_child_raw_tags_need_to_be_closed
-    template = Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+    assert_template_result("", <<~LIQUID.chomp)
       {% comment %}
         {% raw %}
           {% endcomment %}
@@ -51,10 +68,8 @@ class CommentTagUnitTest < Minitest::Test
       {% endcomment %}
     LIQUID
 
-    assert_equal("", template.render)
-
     assert_raises(Liquid::SyntaxError) do
-      Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+      Liquid::Template.parse(<<~LIQUID.chomp)
         {% comment %}
           {% raw %}
           {% endcomment %}