Add support to LiquidDoc with the new {% doc %} tag

lib/liquid/tags.rb

@@ -19,6 +19,7 @@
 require_relative "tags/raw"
 require_relative "tags/render"
 require_relative "tags/cycle"
+require_relative "tags/doc"
 
 module Liquid
   module Tags
@@ -42,6 +43,7 @@ module Tags
       'if' => If,
       'echo' => Echo,
       'tablerow' => TableRow,
+      'doc' => Doc,
     }.freeze
   end
 end

lib/liquid/tags/comment.rb

@@ -15,6 +15,8 @@ module Liquid
   #   {% endcomment %}
   # @liquid_syntax_keyword content The content of the comment.
   class Comment < Block
+    TAG_NAME = "comment"
+
     def render_to_output_buffer(_context, output)
       output
     end
@@ -34,7 +36,10 @@ def parse_body(body, tokenizer)
       end
 
       parse_context.depth += 1
-      comment_tag_depth = 1
+      tag_depth = 1
+
+      begin_tag = self.class::TAG_NAME
+      end_tag = "end#{self.class::TAG_NAME}"
 
       begin
         # Consume tokens without creating child nodes.
@@ -57,13 +62,13 @@ def parse_body(body, tokenizer)
           case tag_name
           when "raw"
             parse_raw_tag_body(tokenizer)
-          when "comment"
-            comment_tag_depth += 1
-          when "endcomment"
-            comment_tag_depth -= 1
+          when begin_tag
+            tag_depth += 1
+          when end_tag
+            tag_depth -= 1
           end
 
-          if comment_tag_depth.zero?
+          if tag_depth.zero?
             parse_context.trim_whitespace = (token[-3] == WhitespaceControl) unless tokenizer.for_liquid_tag
             return false
           end

lib/liquid/tags/doc.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name doc
+  # @liquid_summary
+  #   Documents template elements with annotations.
+  # @liquid_description
+  #   The `doc` tag allows developers to include documentation within Liquid
+  #   templates. Any content inside `doc` tags is not rendered or outputted.
+  #   Liquid code inside will be parsed but not executed. This facilitates
+  #   tooling support for features like code completion, linting, and inline
+  #   documentation.
+  # @liquid_syntax
+  #   {% doc %}
+  #     Renders a message.
+  #
+  #     @param {string} foo - A foo value.
+  #     @param {string} [bar] - An optional bar value.
+  #
+  #     @example
+  #     {% render 'message', foo: 'Hello', bar: 'World' %}
+  #   {% enddoc %}
+  #   {{ foo }}, {{ bar }}!
+  class Doc < Comment
+    TAG_NAME = "doc"
+  end
+end

test/unit/block_unit_test.rb

@@ -47,12 +47,18 @@ def test_variable_many_embedded_fragments
     )
   end
 
-  def test_with_block
+  def test_comment_tag_with_block
     template = Liquid::Template.parse("  {% comment %} {% endcomment %} ")
     assert_equal([String, Comment, String], block_types(template.root.nodelist))
     assert_equal(3, template.root.nodelist.size)
   end
 
+  def test_doc_tag_with_block
+    template = Liquid::Template.parse("  {% doc %} {% enddoc %} ")
+    assert_equal([String, Doc, String], block_types(template.root.nodelist))
+    assert_equal(3, template.root.nodelist.size)
+  end
+
   private
 
   def block_types(nodelist)

test/unit/tags/doc_tag_unit_test.rb

@@ -0,0 +1,199 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class DocTagUnitTest < Minitest::Test
+  def test_doc_inside_liquid_tag
+    assert_template_result('', <<~LIQUID.chomp)
+      {% liquid
+        if 1 != 1
+          doc
+            else
+            echo 123
+          enddoc
+        endif
+      %}
+    LIQUID
+  end
+
+  def test_does_not_parse_nodes_inside_a_doc
+    assert_template_result('', <<~LIQUID.chomp)
+      {% doc %}
+        {% if true %}
+        {% if ... %}
+        {%- for ? -%}
+        {% while true %}
+        {%
+          unless if
+        %}
+        {% endcase %}
+      {% enddoc %}
+    LIQUID
+  end
+
+  def test_allows_unclosed_tags
+    assert_template_result('', <<~LIQUID.chomp)
+      {% doc %}
+        {% if true %}
+      {% enddoc %}
+    LIQUID
+  end
+
+  def test_open_tags_in_doc
+    assert_template_result('', <<~LIQUID.chomp)
+      {% doc %}
+        {% assign a = 123 {% doc %}
+      {% enddoc %}
+    LIQUID
+
+    assert_raises(Liquid::SyntaxError) do
+      assert_template_result('', <<~LIQUID.chomp)
+        {% doc %}
+          {% assign foo = "1"
+        {% enddoc %}
+      LIQUID
+    end
+
+    assert_raises(Liquid::SyntaxError) do
+      assert_template_result('', <<~LIQUID.chomp)
+        {% doc %}
+          {% doc %}
+            {% invalid
+          {% enddoc %}
+        {% enddoc %}
+      LIQUID
+    end
+
+    assert_raises(Liquid::SyntaxError) do
+      assert_template_result('', <<~LIQUID.chomp)
+        {% doc %}
+        {% {{ {%- enddoc %}
+      LIQUID
+    end
+  end
+
+  def test_child_doc_tags_need_to_be_closed
+    assert_template_result('', <<~LIQUID.chomp)
+      {% doc %}
+        {% doc %}
+          {% doc %}{% enddoc %}
+        {% enddoc %}
+      {% enddoc %}
+    LIQUID
+
+    assert_raises(Liquid::SyntaxError) do
+      assert_template_result('', <<~LIQUID.chomp)
+        {% doc %}
+          {% doc %}
+            {% doc %}
+          {% enddoc %}
+        {% enddoc %}
+      LIQUID
+    end
+  end
+
+  def test_child_raw_tags_need_to_be_closed
+    assert_template_result('', <<~LIQUID.chomp)
+      {% doc %}
+        {% raw %}
+          {% enddoc %}
+        {% endraw %}
+      {% enddoc %}
+    LIQUID
+
+    assert_raises(Liquid::SyntaxError) do
+      Liquid::Template.parse(<<~LIQUID.chomp)
+        {% doc %}
+          {% raw %}
+          {% enddoc %}
+        {% enddoc %}
+      LIQUID
+    end
+  end
+
+  def test_error_line_number_is_correct
+    template = Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
+      {% doc %}
+        {% if true %}
+      {% enddoc %}
+      {{ errors.standard_error }}
+    LIQUID
+
+    output = template.render('errors' => ErrorDrop.new)
+    expected = <<~TEXT.chomp
+
+      Liquid error (line 4): standard error
+    TEXT
+
+    assert_equal(expected, output)
+  end
+
+  def test_doc_tag_delimiter_with_extra_strings
+    assert_template_result(
+      '',
+      <<~LIQUID.chomp,
+        {% doc %}
+          {% doc %}
+          {% enddoc
+          {% if true %}
+          {% endif %}
+        {% enddoc %}
+      LIQUID
+    )
+  end
+
+  def test_nested_doc_tag_with_extra_strings
+    assert_template_result(
+      '',
+      <<~LIQUID.chomp,
+        {% doc %}
+          {% doc
+            {% assign foo = 1 %}
+          {% enddoc
+          {% assign foo = 1 %}
+        {% enddoc %}
+      LIQUID
+    )
+  end
+
+  def test_ignores_delimiter_with_extra_strings
+    assert_template_result('', <<~LIQUID.chomp)
+      {% if true %}
+        {% doc %}
+          {% docEXTRA %}wut{% enddocEXTRA %}xyz
+        {% enddoc %}
+      {% endif %}
+    LIQUID
+  end
+
+  def test_delimiter_can_have_extra_strings
+    assert_template_result('', "{% doc %}123{% enddoc xyz %}")
+    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
+
+  def test_with_whitespace_control
+    assert_template_result("Hello!", "      {%- doc -%}123{%- enddoc -%}Hello!")
+    assert_template_result("Hello!", "{%- doc -%}123{%- enddoc -%}     Hello!")
+    assert_template_result("Hello!", "      {%- doc -%}123{%- enddoc -%}     Hello!")
+
+    assert_template_result("Hello!", <<~LIQUID.chomp)
+      {%- doc %}Whitespace control!{% enddoc -%}
+      Hello!
+    LIQUID
+  end
+
+  def test_dont_override_liquid_tag_whitespace_control
+    assert_template_result("Hello!World!", <<~LIQUID.chomp)
+      Hello!
+      {%- liquid
+        doc
+         this is inside a liquid tag
+        enddoc
+      -%}
+      World!
+    LIQUID
+  end
+end