List Files: Catch more Runner::Errors

app/controllers/execution_environments_controller.rb

@@ -44,7 +44,7 @@ class ExecutionEnvironmentsController < ApplicationController
       downloadable_files, additional_directories = convert_files_json_to_files files
       js_tree = FileTree.new(downloadable_files, additional_directories, force_closed: true).to_js_tree
       render json: js_tree[:core][:data]
-    rescue Runner::Error::WorkspaceError
+    rescue Runner::Error::RunnerNotFound, Runner::Error::WorkspaceError
       render json: []
     end
   end

app/models/runner.rb

@@ -77,6 +77,9 @@ class Runner < ApplicationRecord
     ensure
       # We forward the exception if requested
       raise e if raise_exception && defined?(e) && e.present?
+
+      # Otherwise, we return an hash with empty files
+      {'files' => []}
     end
   end