Prevent Error 500s with invalid relative links

https://gitlab.com/gitlab-org/gitlab-ce/issues/52009

changelogs/unreleased/sh-fix-issue-52009.yml

+---
+title: Prevent Error 500s with invalid relative links
+merge_request: 22001
+author:
+type: fixed

lib/banzai/filter/relative_link_filter.rb

@@ -60,7 +60,11 @@ module Banzai
           path_parts.unshift(relative_url_root, project.full_path)
         end
 
-        path = Addressable::URI.escape(File.join(*path_parts))
+        begin
+          path = Addressable::URI.escape(File.join(*path_parts))
+        rescue Addressable::URI::InvalidURIError
+          return
+        end
 
         html_attr.value =
           if context[:only_path]

spec/lib/banzai/filter/relative_link_filter_spec.rb

@@ -83,6 +83,11 @@ describe Banzai::Filter::RelativeLinkFilter do
     expect { filter(act) }.not_to raise_error
   end
 
+  it 'does not raise an exception with a space in the path' do
+    act = link("/uploads/d18213acd3732630991986120e167e3d/Landscape_8.jpg  \nBut here's some more unexpected text :smile:)")
+    expect { filter(act) }.not_to raise_error
+  end
+
   it 'ignores ref if commit is passed' do
     doc = filter(link('non/existent.file'), commit: project.commit('empty-branch') )
     expect(doc.at_css('a')['href'])