From 51307130a2e6dc6da2365f522ebbf2a6da831a29 Mon Sep 17 00:00:00 2001
From: "F. Gold" <fgold@vmware.com>
Date: Thu, 28 Oct 2021 15:37:00 -0700
Subject: [PATCH] Validation allows empty string namespace

Signed-off-by: F. Gold <fgold@vmware.com>
---
 pkg/util/collections/includes_excludes.go      |  6 ++++++
 pkg/util/collections/includes_excludes_test.go | 15 ++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/pkg/util/collections/includes_excludes.go b/pkg/util/collections/includes_excludes.go
index 1f2128c71..231689be0 100644
--- a/pkg/util/collections/includes_excludes.go
+++ b/pkg/util/collections/includes_excludes.go
@@ -180,6 +180,12 @@ func ValidateNamespaceIncludesExcludes(includesList, excludesList []string) []er
 func validateNamespaceName(ns string) []error {
 	var errs []error
 
+	// Velero interprets empty string as "no namespace", so allow it even though
+	// it is not a valid Kubernetes name.
+	if ns == "" {
+		return nil
+	}
+
 	// Kubernetes does not allow asterisks in namespaces but Velero uses them as
 	// wildcards. Replace asterisks with an arbitrary letter to pass Kubernetes
 	// validation.
diff --git a/pkg/util/collections/includes_excludes_test.go b/pkg/util/collections/includes_excludes_test.go
index 0ba885bd2..672a309d2 100644
--- a/pkg/util/collections/includes_excludes_test.go
+++ b/pkg/util/collections/includes_excludes_test.go
@@ -207,11 +207,6 @@ func TestValidateNamespaceIncludesExcludes(t *testing.T) {
 			includes: []string{},
 			wantErr:  false,
 		},
-		{
-			name:     "empty string is invalid",
-			includes: []string{""},
-			wantErr:  true,
-		},
 		{
 			name:     "asterisk by itself is valid",
 			includes: []string{"*"},
@@ -240,6 +235,16 @@ func TestValidateNamespaceIncludesExcludes(t *testing.T) {
 			includes: []string{},
 			wantErr:  false,
 		},
+		{
+			name:     "empty string includes is valid (includes nothing)",
+			includes: []string{""},
+			wantErr:  false,
+		},
+		{
+			name:     "empty string excludes is valid (excludes nothing)",
+			excludes: []string{""},
+			wantErr:  false,
+		},
 		{
 			name:     "include everything using asterisk is valid",
 			includes: []string{"*"},