fix: Fix npe in pagination (#23880)

CHANGELOG.md

@@ -53,6 +53,7 @@ Every module contains its own CHANGELOG.md. Please refer to the module you are i
 ### Bug Fixes
 
 * (x/auth) [#23741](https://github.com/cosmos/cosmos-sdk/pull/23741) Support legacy global AccountNumber.
+* (types/query) [#23880](https://github.com/cosmos/cosmos-sdk/pull/23880) Fix NPE in query pagination.
 
 ### Removed
 

types/query/collections_pagination.go

@@ -112,7 +112,7 @@ func CollectionFilteredPaginate[K, V any, C Collection[K, V], T any](
 		return results, new(PageResponse), nil
 	}
 	// strip the prefix from next key
-	if len(pageRes.NextKey) != 0 && prefix != nil {
+	if pageRes != nil && len(pageRes.NextKey) != 0 && prefix != nil {
 		pageRes.NextKey = pageRes.NextKey[len(prefix):]
 	}
 	return results, pageRes, err

types/query/collections_pagination_test.go

@@ -2,6 +2,7 @@ package query
 
 import (
 	"context"
+	"errors"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -15,6 +16,7 @@ func TestCollectionPagination(t *testing.T) {
 	sk, ctx := deps()
 	sb := collections.NewSchemaBuilder(sk)
 	m := collections.NewMap(sb, collections.NewPrefix(0), "_", collections.Uint64Key, collections.Uint64Value)
+	dummyErr := errors.New("dummy error")
 
 	for i := uint64(0); i < 300; i++ {
 		require.NoError(t, m.Set(ctx, i, i))
@@ -152,6 +154,18 @@ func TestCollectionPagination(t *testing.T) {
 				{Key: 295, Value: 295},
 			},
 		},
+		"filtered no key with error": {
+			req: &PageRequest{
+				Limit: 3,
+			},
+			expResp: &PageResponse{
+				NextKey: encodeKey(5),
+			},
+			filter: func(key, value uint64) (bool, error) {
+				return false, dummyErr
+			},
+			wantErr: dummyErr,
+		},
 	}
 
 	for name, tc := range tcs {