feat(tvix): Thread a log sink through calls to buildDerivation r/1946

Similarly to how we did for buildPaths, add a std::ostream& log_sink
parameter to the build_derivation method on Store, and pass it std::cerr
when called at the top level by nix commands - most notably, the
build-remote hook binary, so that we get build logs when using tvix as a
remote builder.

Change-Id: I0f8f729ba8429d4838a0a135a5c2ac1e1a95d575
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2176
Tested-by: BuildkiteCI
Reviewed-by: andi <andi@notmuch.email>
Reviewed-by: kanepyork <rikingcoding@gmail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/third_party/nix/src/libstore/legacy-ssh-store.cc b/third_party/nix/src/libstore/legacy-ssh-store.cc
index 19603115a81c..8163258179a1 100644
--- a/third_party/nix/src/libstore/legacy-ssh-store.cc
+++ b/third_party/nix/src/libstore/legacy-ssh-store.cc
@@ -199,7 +199,8 @@ struct LegacySSHStore : public Store {
     unsupported("addTextToStore");
   }
 
-  BuildResult buildDerivation(const Path& drvPath, const BasicDerivation& drv,
+  BuildResult buildDerivation(std::ostream& /*log_sink*/, const Path& drvPath,
+                              const BasicDerivation& drv,
                               BuildMode buildMode) override {
     auto conn(connections->get());