fix(graph): nullable latestCloudEvent/latestIndex so empty sources don't tank sibling aliases

internal/graph/null_propagation_test.go

@@ -0,0 +1,130 @@
+package graph
+
+import (
+	"context"
+	"math/big"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/99designs/gqlgen/client"
+	"github.com/99designs/gqlgen/graphql/handler"
+	"github.com/99designs/gqlgen/graphql/handler/transport"
+	chconfig "github.com/DIMO-Network/clickhouse-infra/pkg/connect/config"
+	"github.com/DIMO-Network/clickhouse-infra/pkg/container"
+	"github.com/DIMO-Network/cloudevent"
+	chindexer "github.com/DIMO-Network/cloudevent/clickhouse"
+	"github.com/DIMO-Network/cloudevent/clickhouse/migrations"
+	"github.com/DIMO-Network/fetch-api/pkg/eventrepo"
+	"github.com/DIMO-Network/token-exchange-api/pkg/tokenclaims"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestLatestCloudEvent_AliasedEmptySourceDoesNotTankSiblings is the regression
+// test for the nickname-summary bug: getName batches per-source `latestCloudEvent`
+// lookups as GraphQL aliases in one request. When `latestCloudEvent` (and
+// `latestIndex`) were non-nullable, a source with no matching event returned an
+// error which GraphQL null-propagated up to the root `data`, wiping every
+// sibling alias that DID resolve — so a vehicle whose owner had a nickname but
+// whose dev-license source did not returned no name at all.
+//
+// The fields are now nullable and the resolvers return null (not an error) on
+// no-rows, so one empty source must leave its siblings intact. Exercised against
+// `latestIndex` because it needs only ClickHouse (no blob buckets), but the fix
+// and codepath are identical for `latestCloudEvent`.
+func TestLatestCloudEvent_AliasedEmptySourceDoesNotTankSiblings(t *testing.T) {
+	ctx := context.Background()
+
+	ch, err := container.CreateClickHouseContainer(ctx, chconfig.Settings{User: "default", Database: "dimo"})
+	require.NoError(t, err)
+	t.Cleanup(func() { ch.Terminate(context.Background()) })
+
+	chDB, err := ch.GetClickhouseAsDB()
+	require.NoError(t, err)
+	require.NoError(t, migrations.RunGoose(ctx, []string{"up"}, chDB))
+
+	conn, err := ch.GetClickHouseAsConn()
+	require.NoError(t, err)
+
+	did := cloudevent.ERC721DID{
+		ChainID:         137,
+		ContractAddress: common.HexToAddress("0xbA5738a18d83D41847dfFbDC6101d37C69c9B0cF"),
+		TokenID:         big.NewInt(22892),
+	}.String()
+
+	const (
+		nickType    = "dimo.document.nickname"
+		ownerSource = "0x3Afb7b82D912743F8Fd15f67a9b2095e9d5AD576" // has an event
+		devSource   = "0x299671D2b32ED62Cc61ce65D8f2b9e4f78486B37" // no event
+	)
+
+	// Only the owner source has a nickname event.
+	ownerEvent := &cloudevent.CloudEventHeader{
+		ID:          "owner-nickname-evt",
+		Source:      ownerSource,
+		Subject:     did,
+		Type:        nickType,
+		Time:        time.Now(),
+		DataVersion: "nickname/v1.0.0",
+	}
+	require.NoError(t, conn.Exec(ctx, chindexer.InsertStmt, chindexer.CloudEventToSlice(ownerEvent)...))
+
+	svc := eventrepo.New(conn, nil, nil, "", "")
+	es := NewExecutableSchema(Config{Resolvers: &Resolver{EventService: svc}})
+	srv := handler.New(es)
+	srv.AddTransport(transport.Options{})
+	srv.AddTransport(transport.POST{})
+
+	gql := client.New(injectClaims(srv, did))
+
+	const query = `
+		query($did: String!, $owner: CloudEventFilter, $dev: CloudEventFilter) {
+			owner: latestIndex(did: $did, filter: $owner) { header { source type } }
+			dev:   latestIndex(did: $did, filter: $dev)   { header { source } }
+		}`
+
+	var resp struct {
+		Owner *struct {
+			Header struct {
+				Source string
+				Type   string
+			}
+		}
+		Dev *struct {
+			Header struct{ Source string }
+		}
+	}
+
+	err = gql.Post(
+		query,
+		&resp,
+		client.Var("did", did),
+		client.Var("owner", map[string]any{"source": ownerSource, "type": nickType}),
+		client.Var("dev", map[string]any{"source": devSource, "type": nickType}),
+	)
+
+	// Before the fix: the empty `dev` alias erred on a non-null field, the null
+	// propagated to root `data`, and this Post returned a GraphQL error with no
+	// data — the owner nickname was lost.
+	require.NoError(t, err, "empty source must not tank sibling aliases")
+	require.NotNil(t, resp.Owner, "owner's event must survive a sibling empty source")
+	assert.Equal(t, ownerSource, resp.Owner.Header.Source)
+	assert.Equal(t, nickType, resp.Owner.Header.Type)
+	assert.Nil(t, resp.Dev, "a source with no event must resolve to null, not error")
+}
+
+// injectClaims wraps a handler with the raw-data token the resolvers require,
+// scoped to `asset` (the DID under test) so requireSubjectOptsByDID admits it.
+func injectClaims(next http.Handler, asset string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		tok := &tokenclaims.Token{
+			CustomClaims: tokenclaims.CustomClaims{
+				Asset:       asset,
+				Permissions: []string{tokenclaims.PermissionGetRawData},
+			},
+		}
+		next.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), ClaimsContextKey{}, tok)))
+	})
+}

schema/base.graphqls

@@ -41,11 +41,13 @@ The root query type for the Fetch API GraphQL schema. ERC721 DID (e.g. did:eth:c
 """
 type Query {
   """
-  Latest cloud event index matching filters. Tombstoned attestations are
-  hidden from the result by default; pass includeDeleted: true to disable
-  tombstone suppression.
+  Latest cloud event index matching filters, or null when none match.
+  Nullable so an aliased multi-source query with an empty source resolves to
+  null instead of erroring and null-propagating over its siblings. Tombstoned
+  attestations are hidden from the result by default; pass includeDeleted:
+  true to disable tombstone suppression.
   """
-  latestIndex(did: String!, filter: CloudEventFilter, includeDeleted: Boolean = false): CloudEventIndex!
+  latestIndex(did: String!, filter: CloudEventFilter, includeDeleted: Boolean = false): CloudEventIndex
     @mcpTool(
       name: "get_latest_index"
       description: "Get the latest CloudEvent index entry (header + storage key) for a DID-scoped subject, optionally filtered by event type, source, producer, or time range. Returns metadata only — use fetch_get_latest_cloud_event for the full payload."
@@ -65,11 +67,13 @@ type Query {
     )
 
   """
-  Latest full cloud event. Tombstoned attestations are hidden from the
-  result by default; pass includeDeleted: true to disable tombstone
-  suppression.
+  Latest full cloud event, or null when the subject has no matching event.
+  Nullable so that, in an aliased multi-source query, a source with no event
+  resolves to null instead of erroring and null-propagating over its siblings.
+  Tombstoned attestations are hidden from the result by default; pass
+  includeDeleted: true to disable tombstone suppression.
   """
-  latestCloudEvent(did: String!, filter: CloudEventFilter, includeDeleted: Boolean = false): CloudEvent!
+  latestCloudEvent(did: String!, filter: CloudEventFilter, includeDeleted: Boolean = false): CloudEvent
     @mcpTool(
       name: "get_latest_cloud_event"
       description: "Get the latest full CloudEvent (header + JSON payload) for a DID-scoped subject, optionally filtered. Returns dataUrl (presigned S3 link) for large binary payloads instead of inlining them."