refactor(tvix): Make Store::buildPaths return a Status r/1649

Make Store::buildPaths return a Status with [[nodiscard]] rather than
throwing exceptions to signal failure. This is the beginning of a long
road to refactor the entire store API to be status/statusor based
instead of using exceptions.

Change-Id: I2e32371c95a25b87ad129987c217d49c6d6e0c85
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1745
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/third_party/nix/src/libstore/store-api.cc b/third_party/nix/src/libstore/store-api.cc
index ae403b0be65f..fc33c7ce5711 100644
--- a/third_party/nix/src/libstore/store-api.cc
+++ b/third_party/nix/src/libstore/store-api.cc
@@ -3,6 +3,7 @@
 #include <future>
 #include <utility>
 
+#include <absl/status/status.h>
 #include <absl/strings/match.h>
 #include <absl/strings/numbers.h>
 #include <absl/strings/str_cat.h>
@@ -700,16 +701,20 @@ const Store::Stats& Store::getStats() {
   return stats;
 }
 
-void Store::buildPaths(const PathSet& paths, BuildMode buildMode) {
+absl::Status Store::buildPaths(const PathSet& paths, BuildMode) {
   for (auto& path : paths) {
     if (isDerivation(path)) {
-      unsupported("buildPaths");
+      return absl::Status(absl::StatusCode::kUnimplemented,
+                          "buildPaths is unsupported");
     }
   }
 
   if (queryValidPaths(paths).size() != paths.size()) {
-    unsupported("buildPaths");
+    return absl::Status(absl::StatusCode::kUnimplemented,
+                        "buildPaths is unsupported");
   }
+
+  return absl::OkStatus();
 }
 
 void copyStorePath(ref<Store> srcStore, const ref<Store>& dstStore,