clear cookie if failing

cmd/checkout/utils.go

@@ -68,15 +68,27 @@ func (a *CheckoutPoolServer) reserveInventory(ctx context.Context, grain *checko
 const checkoutCookieName = "checkoutid"
 
 func setCheckoutCookie(w http.ResponseWriter, checkoutId checkout.CheckoutId, tls bool) {
-	http.SetCookie(w, &http.Cookie{
-		Name:     checkoutCookieName,
-		Value:    checkoutId.String(),
-		Secure:   tls,
-		HttpOnly: true,
-		Path:     "/",
-		Expires:  time.Now().AddDate(0, 0, 14),
-		SameSite: http.SameSiteLaxMode,
-	})
+	if checkoutId == 0 {
+		http.SetCookie(w, &http.Cookie{
+			Name:     checkoutCookieName,
+			Value:    checkoutId.String(),
+			Secure:   tls,
+			HttpOnly: true,
+			Path:     "/",
+			Expires:  time.Unix(0, 0),
+			SameSite: http.SameSiteLaxMode,
+		})
+	} else {
+		http.SetCookie(w, &http.Cookie{
+			Name:     checkoutCookieName,
+			Value:    checkoutId.String(),
+			Secure:   tls,
+			HttpOnly: true,
+			Path:     "/",
+			Expires:  time.Now().AddDate(0, 0, 14),
+			SameSite: http.SameSiteLaxMode,
+		})
+	}
 }
 
 func CookieCheckoutIdHandler(fn func(w http.ResponseWriter, r *http.Request, checkoutId checkout.CheckoutId) error) func(w http.ResponseWriter, r *http.Request) {