From 15b2572b951f64f6e11c504639459914adf27015 Mon Sep 17 00:00:00 2001
From: Andrew Jackura <ajackura@google.com>
Date: Thu, 29 Jun 2017 16:28:47 -0700
Subject: [PATCH] Skip blank sources (#101)

---
 daisy/workflow/step_includeworkflow.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/daisy/workflow/step_includeworkflow.go b/daisy/workflow/step_includeworkflow.go
index 003ff5445..a047563a6 100644
--- a/daisy/workflow/step_includeworkflow.go
+++ b/daisy/workflow/step_includeworkflow.go
@@ -60,6 +60,9 @@ func (i *IncludeWorkflow) populate(ctx context.Context, s *Step) error {
 
 	// Copy Sources up to parent resolving relative paths as we go.
 	for k, v := range i.w.Sources {
+		if v == "" {
+			continue
+		}
 		if _, ok := s.w.Sources[k]; ok {
 			return fmt.Errorf("source %q already exists in workflow", k)
 		}