From 52d48b328f51556e5b4700ef9e811471840b5d31 Mon Sep 17 00:00:00 2001
From: james-prysm <90280386+james-prysm@users.noreply.github.com>
Date: Wed, 31 Aug 2022 11:42:49 -0500
Subject: [PATCH] Improve Validator Index RPC Error Handling (#11363)
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* adding in nil check for head

* adding changes based on feedback

* Update beacon-chain/rpc/prysm/v1alpha1/validator/server_test.go

Co-authored-by: Radosław Kapka <rkapka@wp.pl>
---
 beacon-chain/rpc/prysm/v1alpha1/validator/server.go  |  3 +++
 .../rpc/prysm/v1alpha1/validator/server_test.go      | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/server.go b/beacon-chain/rpc/prysm/v1alpha1/validator/server.go
index 03a36117c..ebea1b1dc 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/server.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/server.go
@@ -123,6 +123,9 @@ func (vs *Server) ValidatorIndex(ctx context.Context, req *ethpb.ValidatorIndexR
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, "Could not determine head state: %v", err)
 	}
+	if st == nil || st.IsNil() {
+		return nil, status.Errorf(codes.Internal, "head state is empty")
+	}
 	index, ok := st.ValidatorIndexByPubkey(bytesutil.ToBytes48(req.PublicKey))
 	if !ok {
 		return nil, status.Errorf(codes.NotFound, "Could not find validator index for public key %#x", req.PublicKey)
diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/server_test.go b/beacon-chain/rpc/prysm/v1alpha1/validator/server_test.go
index c93ec9901..0701918c7 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/server_test.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/server_test.go
@@ -48,6 +48,18 @@ func TestValidatorIndex_OK(t *testing.T) {
 	assert.NoError(t, err, "Could not get validator index")
 }
 
+func TestValidatorIndex_StateEmpty(t *testing.T) {
+	Server := &Server{
+		HeadFetcher: &mockChain.ChainService{},
+	}
+	pubKey := pubKey(1)
+	req := &ethpb.ValidatorIndexRequest{
+		PublicKey: pubKey,
+	}
+	_, err := Server.ValidatorIndex(context.Background(), req)
+	assert.ErrorContains(t, "head state is empty", err)
+}
+
 func TestWaitForActivation_ContextClosed(t *testing.T) {
 	beaconState, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Slot:       0,