module GraphQL::Backtrace::Tracer

def trace(key, metadata)
  push_data = case key
  when "lex", "parse"
    # No context here, don't have a query yet
    nil
  when "execute_multiplex", "analyze_multiplex"
    metadata[:multiplex].queries
  when "validate", "analyze_query", "execute_query", "execute_query_lazy"
    metadata[:query] || metadata[:queries]
  when "execute_field", "execute_field_lazy"
    metadata[:context]
  else
    # Custom key, no backtrace data for this
    nil
  end
  if push_data
    execution_context = Thread.current[:graphql_execution_context] ||= []
    if key == "execute_multiplex"
      execution_context.clear
      execution_context.push(push_data)
      begin
        yield
      rescue StandardError => err
        # This is an unhandled error from execution,
        # Re-raise it with a GraphQL trace.
        potential_context = execution_context.last
        if potential_context.is_a?(GraphQL::Query::Context) || potential_context.is_a?(GraphQL::Query::Context::FieldResolutionContext)
          raise TracedError.new(err, potential_context)
        else
          raise
        end
      ensure
        execution_context.clear
      end
    else
      execution_context.push(push_data)
      res = yield
      execution_context.pop
      res
    end
  else
    yield
  end
end