Update the implementation to make {% doc %} as strict as {% raw %}

lib/liquid/locales/en.yml

@@ -2,6 +2,7 @@
   errors:
     syntax:
       tag_unexpected_args: "Syntax Error in '%{tag}' - Valid syntax: %{tag}"
+      block_tag_unexpected_args: "Syntax Error in '%{tag}' - Valid syntax: {% %{tag} %}{% end%{tag} %}"
       assign: "Syntax Error in 'assign' - Valid syntax: assign [var] = [source]"
       capture: "Syntax Error in 'capture' - Valid syntax: capture [var]"
       case: "Syntax Error in 'case' - Valid syntax: case [condition]"

lib/liquid/tags/doc.rb

@@ -25,45 +25,44 @@ module Liquid
   #   {% enddoc %}
   #   {{ foo }}, {{ bar }}!
   class Doc < Block
-    def render_to_output_buffer(_context, output)
-      output
+    TAG_UNEXPECTED_ARGS = /\A\s*\z/
+
+    def initialize(tag_name, markup, parse_context)
+      super
+      ensure_valid_markup(tag_name, markup, parse_context)
     end
 
-    def unknown_tag(_tag, _markup, _tokens)
-    end
+    def parse(tokens)
+      while (token = tokens.shift)
+        tag_name = token =~ BlockBody::FullTokenPossiblyInvalid && Regexp.last_match(2)
 
-    def blank?
-      true
-    end
+        raise_nested_doc_error if tag_name == @tag_name
 
-    def parse_body(body, tokenizer)
-      while (token = tokenizer.send(:shift))
-        tag_name = if tokenizer.for_liquid_tag
-          next if token.empty? || token.match?(BlockBody::WhitespaceOrNothing)
-
-          tag_name_match = BlockBody::LiquidTagToken.match(token)
-
-          next if tag_name_match.nil?
-
-          tag_name_match[1]
-        else
-          token =~ BlockBody::FullToken
-          Regexp.last_match(2)
-        end
-
-        raise_nested_doc_error if tag_name == "doc"
-
-        if tag_name == "enddoc"
-          parse_context.trim_whitespace = (token[-3] == WhitespaceControl) unless tokenizer.for_liquid_tag
-          return false
+        if tag_name == block_delimiter
+          parse_context.trim_whitespace = (token[-3] == WhitespaceControl)
+          return
         end
       end
 
       raise_tag_never_closed(block_name)
     end
 
+    def render_to_output_buffer(_context, output)
+      output
+    end
+
+    def blank?
+      true
+    end
+
     private
 
+    def ensure_valid_markup(tag_name, markup, parse_context)
+      unless TAG_UNEXPECTED_ARGS.match?(markup)
+        raise SyntaxError, parse_context.locale.t("errors.syntax.block_tag_unexpected_args", tag: tag_name)
+      end
+    end
+
     def raise_nested_doc_error
       raise SyntaxError, parse_context.locale.t("errors.syntax.doc_invalid_nested")
     end

test/unit/tags/doc_tag_unit_test.rb

@@ -20,32 +20,26 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result('', template)
   end
 
-  def test_doc_tag_inside_liquid_tag
+  def test_doc_tag_does_not_support_extra_arguments
+    error = assert_raises(Liquid::SyntaxError) do
       template = <<~LIQUID.chomp
-      {% liquid
-        doc
-          Assigns foo to 1.
-        enddoc
-        assign foo = 1
-      %}
+        {% doc extra %}
+        {% enddoc %}
       LIQUID
 
-    assert_template_result('', template)
+      Liquid::Template.parse(template)
     end
 
-  def test_doc_tag_inside_liquid_tag_with_control_flow_nodes
-    template = <<~LIQUID.chomp
-      {% liquid
-        if 1 != 1
-          doc
-            else
-            echo 123
-          enddoc
-        endif
-      %}
-    LIQUID
+    exp_error = "Liquid syntax error: Syntax Error in 'doc' - Valid syntax: {% doc %}{% enddoc %}"
+    act_error = error.message
 
-    assert_template_result('', template)
+    assert_equal(exp_error, act_error)
+  end
+
+  def test_doc_tag_must_support_valid_tags
+    assert_match_syntax_error("Liquid syntax error (line 1): 'doc' tag was never closed", '{% doc %} foo')
+    assert_match_syntax_error("Liquid syntax error (line 1): Syntax Error in 'doc' - Valid syntax: {% doc %}{% enddoc %}", '{% doc } foo {% enddoc %}')
+    assert_match_syntax_error("Liquid syntax error (line 1): Syntax Error in 'doc' - Valid syntax: {% doc %}{% enddoc %}", '{% doc } foo %}{% enddoc %}')
   end
 
   def test_doc_tag_ignores_liquid_nodes
@@ -103,37 +97,23 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result('', template)
   end
 
-  def test_doc_tag_raises_an_error_for_unclosed_assign
-    error = assert_raises(Liquid::SyntaxError) do
+  def test_doc_tag_ignores_unclosed_assign
     template = <<~LIQUID.chomp
       {% doc %}
         {% assign foo = "1"
       {% enddoc %}
     LIQUID
 
-      Liquid::Template.parse(template)
+    assert_template_result('', template)
   end
 
-    exp_error = "Liquid syntax error: 'doc' tag was never closed"
-    act_error = error.message
-
-    assert_equal(exp_error, act_error)
-  end
-
-  def test_doc_tag_raises_an_error_for_malformed_syntax
-    error = assert_raises(Liquid::SyntaxError) do
+  def test_doc_tag_ignores_malformed_syntax
     template = <<~LIQUID.chomp
       {% doc %}
       {% {{ {%- enddoc %}
     LIQUID
 
-      Liquid::Template.parse(template)
-    end
-
-    exp_error = "Liquid syntax error: 'doc' tag was never closed"
-    act_error = error.message
-
-    assert_equal(exp_error, act_error)
+    assert_template_result('', template)
   end
 
   def test_doc_tag_preserves_error_line_numbers
@@ -157,19 +137,6 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result("Hello!", "      {%- doc -%}123{%- enddoc -%}Hello!")
     assert_template_result("Hello!", "{%- doc -%}123{%- enddoc -%}     Hello!")
     assert_template_result("Hello!", "      {%- doc -%}123{%- enddoc -%}     Hello!")
-
-    # Whitespace control within liquid tags
-    assert_template_result("Hello!World!", <<~LIQUID.chomp)
-      Hello!
-      {%- liquid
-        doc
-         this is inside a liquid tag
-        enddoc
-      -%}
-      World!
-    LIQUID
-
-    # Multiline whitespace control
     assert_template_result("Hello!", <<~LIQUID.chomp)
       {%- doc %}Whitespace control!{% enddoc -%}
       Hello!
@@ -189,6 +156,5 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result('', "{% doc %}123{% enddoc\txyz %}")
     assert_template_result('', "{% doc %}123{% enddoc\nxyz %}")
     assert_template_result('', "{% doc %}123{% enddoc\n   xyz  enddoc %}")
-    assert_template_result('', "{%doc}{% assign a = 1 %}{%enddoc}{% endif %}")
   end
 end