Fix double brackets being linkified in wiki markdown

changelogs/unreleased/18524-fix-double-brackets-in-wiki-markdown.yml

+---
+title: Fix double-brackets being linkified in wiki markdown
+merge_request: 18524
+author: brewingcode
+type: fixed

lib/banzai/filter/gollum_tags_filter.rb

@@ -58,6 +58,9 @@ module Banzai
 
       def call
         doc.search(".//text()").each do |node|
+          # Do not perform linking inside <code> blocks
+          next unless node.ancestors('code').empty?
+
           # A Gollum ToC tag is `[[_TOC_]]`, but due to MarkdownFilter running
           # before this one, it will be converted into `[[<em>TOC</em>]]`, so it
           # needs special-case handling

spec/features/projects/wiki/markdown_preview_spec.rb

@@ -155,4 +155,27 @@ feature 'Projects > Wiki > User previews markdown changes', :js do
       end
     end
   end
+
+  it "does not linkify double brackets inside code blocks as expected" do
+    click_link 'New page'
+    page.within '#modal-new-wiki' do
+      fill_in :new_wiki_path, with: 'linkify_test'
+      click_button 'Create page'
+    end
+
+    page.within '.wiki-form' do
+      fill_in :wiki_content, with: <<-HEREDOC
+        `[[do_not_linkify]]`
+        ```
+        [[also_do_not_linkify]]
+        ```
+      HEREDOC
+      click_on "Preview"
+    end
+
+    expect(page).to have_content("do_not_linkify")
+
+    expect(page.html).to include('[[do_not_linkify]]')
+    expect(page.html).to include('[[also_do_not_linkify]]')
+  end
 end

spec/lib/banzai/filter/gollum_tags_filter_spec.rb

@@ -91,6 +91,12 @@ describe Banzai::Filter::GollumTagsFilter do
       expect(doc.at_css('a').text).to eq 'link-text'
       expect(doc.at_css('a')['href']).to eq expected_path
     end
+
+    it "inside back ticks will be exempt from linkification" do
+      doc = filter('<code>[[link-in-backticks]]</code>', project_wiki: project_wiki)
+
+      expect(doc.at_css('code').text).to eq '[[link-in-backticks]]'
+    end
   end
 
   context 'table of contents' do