From 24ef5e83bffc4ac6f4355aab04fd4dbafd7423da Mon Sep 17 00:00:00 2001
From: "R.B. Boyer" <rb@hashicorp.com>
Date: Mon, 18 Sep 2023 15:05:19 -0500
Subject: [PATCH] ignore nil pointer deref

---
 internal/mesh/internal/types/upstreams.go      |  3 +++
 internal/mesh/internal/types/upstreams_test.go | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/internal/mesh/internal/types/upstreams.go b/internal/mesh/internal/types/upstreams.go
index 90f196243905..54baeceebff7 100644
--- a/internal/mesh/internal/types/upstreams.go
+++ b/internal/mesh/internal/types/upstreams.go
@@ -47,6 +47,9 @@ func MutateUpstreams(res *pbresource.Resource) error {
 	changed := false
 
 	for _, dest := range destinations.Upstreams {
+		if dest.DestinationRef == nil {
+			continue // skip; let the validation hook error out instead
+		}
 		if dest.DestinationRef.Tenancy != nil && !isLocalPeer(dest.DestinationRef.Tenancy.PeerName) {
 			// TODO(peering/v2): remove this bypass when we know what to do with
 			// non-local peer references.
diff --git a/internal/mesh/internal/types/upstreams_test.go b/internal/mesh/internal/types/upstreams_test.go
index 5e5e7e68c5ad..ca4b2ce9b4f1 100644
--- a/internal/mesh/internal/types/upstreams_test.go
+++ b/internal/mesh/internal/types/upstreams_test.go
@@ -48,6 +48,18 @@ func TestMutateUpstreams(t *testing.T) {
 			data:   &pbmesh.Upstreams{},
 			expect: &pbmesh.Upstreams{},
 		},
+		"invalid/nil dest ref": {
+			data: &pbmesh.Upstreams{
+				Upstreams: []*pbmesh.Upstream{
+					{DestinationRef: nil},
+				},
+			},
+			expect: &pbmesh.Upstreams{ // untouched
+				Upstreams: []*pbmesh.Upstream{
+					{DestinationRef: nil},
+				},
+			},
+		},
 		"dest ref tenancy defaulting": {
 			tenancy: newTestTenancy("foo.bar"),
 			data: &pbmesh.Upstreams{