From 2d55ffbd283d9f64d3260c44874bcea864dc9a4d Mon Sep 17 00:00:00 2001
From: "Jason E. Aten" <jason.aten@molecula.com>
Date: Thu, 29 Oct 2020 02:44:22 +0000
Subject: [PATCH] short circuit if no data to migrate

---
 txfactory.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/txfactory.go b/txfactory.go
index 3309884e6..17ef34c75 100644
--- a/txfactory.go
+++ b/txfactory.go
@@ -1327,7 +1327,12 @@ func (f *TxFactory) green2blue(holder *Holder) (err error) {
 	if err != nil {
 		return errors.Wrap(err, "TxFactory.green2blue f.greenHasData()")
 	}
-	if blueHasData && !greenHasData {
+	if !blueHasData && !greenHasData {
+		holder.Logger.Printf("no data in blue or green. No migration or verification to do.")
+		return nil
+	}
+	// INVAR: blue has data.
+	if !greenHasData {
 		holder.Logger.Printf("error: cannot migrate from green '%v' because it has no data in it.", greenSrc)
 		return fmt.Errorf("error: cannot migrate from green '%v' because it has no data in it.", greenSrc)
 	}