Replace [[_TOC_]] tag even if toc result is blank

lib/banzai/filter/gollum_tags_filter.rb

@@ -26,6 +26,10 @@ module Banzai
     #   * [[http://example.com/images/logo.png]]
     #   * [[http://example.com/images/logo.png|alt=Logo]]
     #
+    # - Insert a Table of Contents list:
+    #
+    #   * [[_TOC_]]
+    #
     # Based on Gollum::Filter::Tags
     #
     # Context options:
@@ -61,8 +65,6 @@ module Banzai
           # before this one, it will be converted into `[[<em>TOC</em>]]`, so it
           # needs special-case handling
           if toc_tag?(node)
-            next unless result[:toc].present?
-
             process_toc_tag(node)
           else
             content = node.content
@@ -85,7 +87,7 @@ module Banzai
       # Replace an entire `[[<em>TOC</em>]]` node with the result generated by
       # TableOfContentsFilter
       def process_toc_tag(node)
-        node.parent.parent.replace(result[:toc])
+        node.parent.parent.replace(result[:toc].presence || '')
       end
 
       # Process a single tag into its final HTML form.

spec/lib/banzai/filter/gollum_tags_filter_spec.rb

@@ -95,10 +95,10 @@ describe Banzai::Filter::GollumTagsFilter, lib: true do
     end
 
     it 'handles an empty ToC result' do
-      input = output = "<p>[[<em>TOC</em>]]</p>"
+      input = "<p>[[<em>TOC</em>]]</p>"
       doc = described_class.call(input, project_wiki: project_wiki)
 
-      expect(doc.to_html).to eq output
+      expect(doc.to_html).to eq ''
     end
   end
 end

spec/lib/banzai/pipeline/wiki_pipeline_spec.rb

@@ -46,7 +46,7 @@ describe Banzai::Pipeline::WikiPipeline do
 
       aggregate_failures do
         expect(output).not_to include('<ul>')
-        expect(output).to include('[[<em>TOC</em>]]')
+        expect(output).not_to include('[[<em>TOC</em>]]')
       end
     end
   end