@@ -195,6 +195,10 @@ func parseMultipartForm(r *http.Request) error {

 }

 func httpError(w http.ResponseWriter, err error) {

+	if err == nil || w == nil {

+		logrus.WithFields(logrus.Fields{"error": err, "writer": w}).Error("unexpected HTTP error handling")

+		return

+	}

 	statusCode := http.StatusInternalServerError

 	// FIXME: this is brittle and should not be necessary.

 	// If we need to differentiate between different possible error types, we should

@@ -214,10 +218,8 @@ func httpError(w http.ResponseWriter, err error) {

 		statusCode = http.StatusForbidden

 	}

-	if err != nil {

-		logrus.Errorf("HTTP Error: statusCode=%d %v", statusCode, err)

-		http.Error(w, err.Error(), statusCode)

-	}

+	logrus.WithFields(logrus.Fields{"statusCode": statusCode, "err": err}).Error("HTTP Error")

+	http.Error(w, err.Error(), statusCode)

 }

 // writeJSONEnv writes the engine.Env values to the http response stream as a