Re-implement handling Liquid blocks in excerpts

lib/jekyll/excerpt.rb

@@ -131,36 +131,45 @@ def render_with_liquid?
     #
     # Returns excerpt String
 
-    LIQUID_TAG_REGEX = %r!{%-?\s*(\w+).+\s*-?%}!m
+    LIQUID_TAG_REGEX = %r!{%-?\s*(\w+)\s*.*?-?%}!m
     MKDWN_LINK_REF_REGEX = %r!^ {0,3}\[[^\]]+\]:.+$!
 
     def extract_excerpt(doc_content)
       head, _, tail = doc_content.to_s.partition(doc.excerpt_separator)
 
-      # append appropriate closing tag (to a Liquid block), to the "head" if the
-      # partitioning resulted in leaving the closing tag somewhere in the "tail"
-      # partition.
+      # append appropriate closing tag(s) (for each Liquid block), to the `head` if the
+      # partitioning resulted in leaving the closing tag somewhere in the `tail` partition.
       if head.include?("{%")
-        head =~ LIQUID_TAG_REGEX
-        tag_name = Regexp.last_match(1)
-
-        if liquid_block?(tag_name) && head.match(%r!{%-?\s*end#{tag_name}\s*-?%}!).nil?
-          print_build_warning
+        modified  = false
+        tag_names = head.scan(LIQUID_TAG_REGEX)
+        tag_names.flatten!
+        tag_names.reverse_each do |tag_name|
+          next unless liquid_block?(tag_name)
+          next if head =~ endtag_regex_stash(tag_name)
+
+          modified = true
           head << "\n{% end#{tag_name} %}"
         end
+        print_build_warning if modified
       end
 
-      if tail.empty?
-        head
-      else
-        head.to_s.dup << "\n\n" << tail.scan(MKDWN_LINK_REF_REGEX).join("\n")
-      end
+      return head if tail.empty?
+
+      head << "\n\n" << tail.scan(MKDWN_LINK_REF_REGEX).join("\n")
     end
 
     private
 
+    def endtag_regex_stash(tag_name)
+      @endtag_regex_stash ||= {}
+      @endtag_regex_stash[tag_name] ||= %r!{%-?\s*end#{tag_name}.*?\s*-?%}!m
+    end
+
     def liquid_block?(tag_name)
-      Liquid::Template.tags[tag_name].superclass == Liquid::Block
+      return false unless tag_name.is_a?(String)
+      return false if tag_name.start_with?("end")
+
+      Liquid::Template.tags[tag_name].ancestors.include?(Liquid::Block)
     rescue NoMethodError
       Jekyll.logger.error "Error:",
                           "A Liquid tag in the excerpt of #{doc.relative_path} couldn't be parsed."
@@ -169,12 +178,11 @@ def liquid_block?(tag_name)
 
     def print_build_warning
       Jekyll.logger.warn "Warning:", "Excerpt modified in #{doc.relative_path}!"
-      Jekyll.logger.warn "",
-                         "Found a Liquid block containing separator '#{doc.excerpt_separator}'" \
-                         " and has been modified with the appropriate closing tag."
-      Jekyll.logger.warn "",
-                         "Feel free to define a custom excerpt or excerpt_separator in the" \
-                         " document's Front Matter if the generated excerpt is unsatisfactory."
+      Jekyll.logger.warn "", "Found a Liquid block containing the excerpt separator" \
+                         " #{doc.excerpt_separator.inspect}. "
+      Jekyll.logger.warn "", "The block has been modified with the appropriate closing tag."
+      Jekyll.logger.warn "", "Feel free to define a custom excerpt or excerpt_separator in the"
+      Jekyll.logger.warn "", "document's Front Matter if the generated excerpt is unsatisfactory."
     end
   end
 end

test/source/_posts/2018-01-28-closed-liquid-block-excerpt.markdown

@@ -2,10 +2,23 @@
 layout: post
 ---
 
-{% if
-  page.layout == "post" %}
-You’ll find this post in your `_posts` directory.
-To add new posts, simply add a file in the `_posts` directory.
-{% endif %}
+{%
+  highlight
+  ruby
+%}
+{% assign foo = 'foobar' %}
+{% raw
+%}
+def print_hi(name)
+  puts "Hi, #{name}"
+end
+print_hi('Tom')
+#=> prints 'Hi, Tom' to STDOUT.
+{%
+  endraw
+%}
+{%
+  endhighlight
+%}
 
 So let's talk business.

test/source/_posts/2018-01-28-open-liquid-block-excerpt.markdown

@@ -2,10 +2,20 @@
 layout: post
 ---
 
-{% if page.layout == "post" %}
-  You’ll find this post in your `_posts` directory.
+{%
+  highlight
+  ruby
+%}
+{% assign foo = 'foobar' %}
+{% raw
+%}
+def print_hi(name)
+  puts "Hi, #{name}"
+end
 
-{% else %}
+print_hi('Tom')
+#=> prints 'Hi, Tom' to STDOUT.
+{% endraw %}
+{% endhighlight %}
 
-  To add new posts, simply add a file in the `_posts` directory.
-{% endif %}
+So let's talk business.

test/test_excerpt.rb

@@ -184,12 +184,17 @@ def do_render(document)
       @post = setup_post("2018-01-28-open-liquid-block-excerpt.markdown")
       @excerpt = @post.data["excerpt"]
 
-      assert_includes @post.content, "{% if"
-      refute_includes @post.content.split("\n\n")[0], "{% endif %}"
+      head = @post.content.split("\n\n")[0]
+
+      assert_includes @post.content, "{%\n  highlight\n"
+      assert_includes @post.content, "{% raw"
+      refute_includes head, "{% endraw %}"
+      refute_includes head, "{% endhighlight %}"
     end
 
     should "be appended to as necessary and generated" do
-      assert_includes @excerpt.content, "{% endif %}"
+      assert_includes @excerpt.content, "{% endraw %}"
+      assert_includes @excerpt.content, "{% endhighlight %}"
       assert_equal true, @excerpt.is_a?(Jekyll::Excerpt)
     end
   end
@@ -201,13 +206,19 @@ def do_render(document)
       @post = setup_post("2018-01-28-closed-liquid-block-excerpt.markdown")
       @excerpt = @post.data["excerpt"]
 
-      assert_includes @post.content, "{% if"
-      assert_includes @post.content.split("\n\n")[0], "{% endif %}"
+      head = @post.content.split("\n\n")[0]
+
+      assert_includes @post.content, "{%\n  highlight\n"
+      assert_includes @post.content, "{% raw"
+      assert_includes head, "{%\n  endraw\n%}"
+      assert_includes head, "{%\n  endhighlight\n%}"
     end
 
     should "not be appended to but generated as is" do
-      assert_includes @excerpt.content, "{% endif %}"
-      refute_includes @excerpt.content, "{% endif %}\n\n{% endif %}"
+      assert_includes @excerpt.content, "{%\n  endraw\n%}"
+      assert_includes @excerpt.content, "{%\n  endhighlight\n%}"
+      refute_includes @excerpt.content, "{%\n  endraw\n%}\n\n{% endraw %}"
+      refute_includes @excerpt.content, "{%\n  endhighlight\n%}\n\n{% endhighlight %}"
       assert_equal true, @excerpt.is_a?(Jekyll::Excerpt)
     end
   end