Merge branch 'fj-fix-bug-with-wiki-link-rewriter' into 'master'

Fix bug in wiki link rewriter filter

See merge request gitlab-org/gitlab!56636

changelogs/unreleased/fj-fix-bug-with-wiki-link-rewriter.yml

+---
+title: Fix bug in wiki link rewriter filter
+merge_request: 56636
+author:
+type: fixed

lib/banzai/filter/wiki_link_filter/rewriter.rb

@@ -6,7 +6,7 @@ module Banzai
       class Rewriter
         def initialize(link_string, wiki:, slug:)
           @uri = Addressable::URI.parse(link_string)
-          @wiki_base_path = wiki && wiki.wiki_base_path
+          @wiki_base_path = wiki&.wiki_base_path
           @slug = slug
         end
 
@@ -41,7 +41,8 @@ module Banzai
         # Any link _not_ of the form `http://example.com/`
         def apply_relative_link_rules!
           if @uri.relative? && @uri.path.present?
-            link = ::File.join(@wiki_base_path, @uri.path)
+            link = @uri.path
+            link = ::File.join(@wiki_base_path, link) unless link.starts_with?(@wiki_base_path)
             link = "#{link}##{@uri.fragment}" if @uri.fragment
             @uri = Addressable::URI.parse(link)
           end

spec/lib/banzai/filter/wiki_link_filter_spec.rb

@@ -22,6 +22,15 @@ RSpec.describe Banzai::Filter::WikiLinkFilter do
     expect(filtered_link.attribute('href').value).to eq('/uploads/a.test')
   end
 
+  describe 'when links point to the relative wiki path' do
+    it 'does not rewrite links' do
+      path = "#{wiki.wiki_base_path}/#{repository_upload_folder}/a.jpg"
+      filtered_link = filter("<a href='#{path}'>Link</a>", wiki: wiki, page_slug: 'home').children[0]
+
+      expect(filtered_link.attribute('href').value).to eq(path)
+    end
+  end
+
   describe "when links point to the #{Wikis::CreateAttachmentService::ATTACHMENT_PATH} folder" do
     context 'with an "a" html tag' do
       it 'rewrites links' do