1 files changed, 2 insertions, 1 deletions
diff --git a/src/buildtool/execution_api/local/local_api.hpp b/src/buildtool/execution_api/local/local_api.hpp
index a5596350..dfe8be21 100644
--- a/src/buildtool/execution_api/local/local_api.hpp
+++ b/src/buildtool/execution_api/local/local_api.hpp
@@ -64,7 +64,8 @@ class LocalApi final : public IExecutionApi {
     [[nodiscard]] auto RetrieveToPaths(
         std::vector<Artifact::ObjectInfo> const& artifacts_info,
         std::vector<std::filesystem::path> const& output_paths,
-        IExecutionApi* /*alternative*/ = nullptr) noexcept -> bool final {
+        std::optional<gsl::not_null<IExecutionApi*>> const& /*alternative*/ =
+            std::nullopt) noexcept -> bool final {
         if (artifacts_info.size() != output_paths.size()) {
             Logger::Log(LogLevel::Error,
                         "different number of digests and output paths.");