Fix a 500 error in the SSH host keys lookup action

changelogs/unreleased-ee/3312-fix-500-in-ssh-host-keys-action.yml

+---
+title: Fix a 500 error in the SSH host keys lookup action
+merge_request: 2827
+author:
+type: fixed

ee/app/models/ssh_host_key.rb

@@ -125,5 +125,7 @@ class SshHostKey
     raise ArgumentError.new("Invalid URL") unless full_url&.scheme == 'ssh'
 
     Addressable::URI.parse("ssh://#{full_url.host}:#{full_url.inferred_port}")
+  rescue Addressable::URI::InvalidURIError
+    raise ArgumentError.new("Invalid URL")
   end
 end

spec/controllers/projects/mirrors_controller_spec.rb

@@ -223,14 +223,18 @@ describe Projects::MirrorsController do
       sign_in(project.owner)
     end
 
-    context 'invalid URL' do
+    context 'invalid URLs' do
+      where(url: %w[INVALID git@example.com:foo/bar.git ssh://git@example.com:foo/bar.git])
+
+      with_them do
         it 'returns an error with a 400 response' do
-        do_get(project, 'INVALID URL')
+          do_get(project, url)
 
           expect(response).to have_http_status(400)
           expect(json_response).to eq('message' => 'Invalid URL')
         end
       end
+    end
 
     context 'no data in cache' do
       it 'requests the cache to be filled and returns a 204 response' do