Do not process upload links if no project context

lib/banzai/filter/upload_link_filter.rb

@@ -8,6 +8,8 @@ module Banzai
     #
     class UploadLinkFilter < HTML::Pipeline::Filter
       def call
+        return doc unless project
+
         doc.search('a').each do |el|
           process_link_attr el.attribute('href')
         end
@@ -31,11 +33,13 @@ module Banzai
       end
 
       def build_url(uri)
-        return '#' unless project = context[:project]
-
         File.join(Gitlab.config.gitlab.url, project.path_with_namespace, uri)
       end
 
+      def project
+        context[:project]
+      end
+
       # Ensure that a :project key exists in context
       #
       # Note that while the key might exist, its value could be nil!

spec/lib/banzai/filter/upload_link_filter_spec.rb

@@ -79,13 +79,13 @@ describe Banzai::Filter::UploadLinkFilter, lib: true do
     let(:upload_link) { link('/uploads/e90decf88d8f96fe9e1389afc2e4a91f/test.jpg') }
 
     it 'does not raise error' do
-      expect { raw_filter(upload_link, project: nil) }.to_not raise_error
+      expect { raw_filter(upload_link, project: nil) }.not_to raise_error
     end
 
-    it 'provides an empty link' do
+    it 'does not rewrite link' do
       doc = raw_filter(upload_link, project: nil)
 
-      expect(doc.at_css('a')['href']).to eq '#'
+      expect(doc.to_html).to eq upload_link
     end
   end
 end