From 198ea77f1de283c5097392337d75d8e74b33335a Mon Sep 17 00:00:00 2001
From: Natalie Diaz <nhdiaz@google.com>
Date: Tue, 3 Mar 2026 14:23:03 -0800
Subject: [PATCH 1/2] Add default response message type for v3 sparql

---
 internal/server/redis/processor.go      | 4 ++++
 internal/server/redis/processor_test.go | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/internal/server/redis/processor.go b/internal/server/redis/processor.go
index bf1ac1897..1a7b397a0 100644
--- a/internal/server/redis/processor.go
+++ b/internal/server/redis/processor.go
@@ -18,6 +18,7 @@ import (
 	"context"
 	"log/slog"
 
+	pb "github.com/datacommonsorg/mixer/internal/proto"
 	pbv2 "github.com/datacommonsorg/mixer/internal/proto/v2"
 	"github.com/datacommonsorg/mixer/internal/server/dispatcher"
 	"github.com/datacommonsorg/mixer/internal/util"
@@ -77,7 +78,10 @@ func newEmptyResponse(requestType dispatcher.RequestType) proto.Message {
 		return &pbv2.ObservationResponse{}
 	case dispatcher.TypeResolve:
 		return &pbv2.ResolveResponse{}
+	case dispatcher.TypeSparql:
+		return &pb.QueryResponse{}
 	default:
+		slog.Error("Unknown request type for caching", "requestType", requestType)
 		return nil
 	}
 }
diff --git a/internal/server/redis/processor_test.go b/internal/server/redis/processor_test.go
index 73cb694f6..fbba0fce3 100644
--- a/internal/server/redis/processor_test.go
+++ b/internal/server/redis/processor_test.go
@@ -20,6 +20,7 @@ import (
 	"testing"
 	"time"
 
+	pb "github.com/datacommonsorg/mixer/internal/proto"
 	pbv2 "github.com/datacommonsorg/mixer/internal/proto/v2"
 	"github.com/datacommonsorg/mixer/internal/server/dispatcher"
 	"github.com/datacommonsorg/mixer/internal/util"
@@ -255,6 +256,11 @@ func TestNewEmptyResponse(t *testing.T) {
 			requestType: dispatcher.TypeResolve,
 			want:        &pbv2.ResolveResponse{},
 		},
+		{
+			name:        "Sparql",
+			requestType: dispatcher.TypeSparql,
+			want:        &pb.QueryResponse{},
+		},
 	}
 
 	for _, test := range tests {

From 6895283ab0004d8dbe134300128d975ae3447e1c Mon Sep 17 00:00:00 2001
From: Natalie Diaz <nhdiaz@google.com>
Date: Tue, 3 Mar 2026 14:37:38 -0800
Subject: [PATCH 2/2] propgate error

---
 internal/server/redis/processor.go      | 22 +++++++++++++---------
 internal/server/redis/processor_test.go |  3 ++-
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/internal/server/redis/processor.go b/internal/server/redis/processor.go
index 1a7b397a0..199535161 100644
--- a/internal/server/redis/processor.go
+++ b/internal/server/redis/processor.go
@@ -16,6 +16,7 @@ package redis
 
 import (
 	"context"
+	"fmt"
 	"log/slog"
 
 	pb "github.com/datacommonsorg/mixer/internal/proto"
@@ -40,7 +41,11 @@ func (processor *CacheProcessor) PreProcess(rc *dispatcher.RequestContext) (disp
 		return dispatcher.Continue, nil
 	}
 
-	cachedResponse := newEmptyResponse(rc.Type)
+	cachedResponse, err := newEmptyResponse(rc.Type)
+	if err != nil {
+		slog.Error("Skipping cache", "error", err)
+		return dispatcher.Continue, err
+	}
 	if found, err := processor.client.GetCachedResponse(rc.Context, rc.OriginalRequest, cachedResponse); found {
 		slog.Info("Cache hit", "originalRequest", rc.OriginalRequest)
 
@@ -68,21 +73,20 @@ func (processor *CacheProcessor) PostProcess(rc *dispatcher.RequestContext) (dis
 }
 
 // newEmptyResponse returns a new empty response for the given request type.
-func newEmptyResponse(requestType dispatcher.RequestType) proto.Message {
+func newEmptyResponse(requestType dispatcher.RequestType) (proto.Message, error) {
 	switch requestType {
 	case dispatcher.TypeNode:
-		return &pbv2.NodeResponse{}
+		return &pbv2.NodeResponse{}, nil
 	case dispatcher.TypeNodeSearch:
-		return &pbv2.NodeSearchResponse{}
+		return &pbv2.NodeSearchResponse{}, nil
 	case dispatcher.TypeObservation:
-		return &pbv2.ObservationResponse{}
+		return &pbv2.ObservationResponse{}, nil
 	case dispatcher.TypeResolve:
-		return &pbv2.ResolveResponse{}
+		return &pbv2.ResolveResponse{}, nil
 	case dispatcher.TypeSparql:
-		return &pb.QueryResponse{}
+		return &pb.QueryResponse{}, nil
 	default:
-		slog.Error("Unknown request type for caching", "requestType", requestType)
-		return nil
+		return nil, fmt.Errorf("unknown request type for caching: %v", requestType)
 	}
 }
 
diff --git a/internal/server/redis/processor_test.go b/internal/server/redis/processor_test.go
index fbba0fce3..0e1f6b6be 100644
--- a/internal/server/redis/processor_test.go
+++ b/internal/server/redis/processor_test.go
@@ -265,7 +265,8 @@ func TestNewEmptyResponse(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			got := newEmptyResponse(test.requestType)
+			got, err := newEmptyResponse(test.requestType)
+			assert.NoError(t, err)
 			assert.True(t, proto.Equal(test.want, got))
 		})
 	}