2 files changed, 19 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/store-api.cc b/third_party/nix/src/libstore/store-api.cc
index fc33c7ce57..3ada63532c 100644
--- a/third_party/nix/src/libstore/store-api.cc
+++ b/third_party/nix/src/libstore/store-api.cc
@@ -1,6 +1,8 @@
 #include "libstore/store-api.hh"
 
 #include <future>
+#include <ostream>
+#include <streambuf>
 #include <utility>
 
 #include <absl/status/status.h>
@@ -23,6 +25,17 @@
 
 namespace nix {
 
+namespace {
+class NullStream : public std::streambuf {
+ public:
+  int overflow(int c) override { return c; }
+};
+
+static NullStream NULL_STREAM{};
+}  // namespace
+
+std::ostream DiscardLogsSink() { return std::ostream(&NULL_STREAM); }
+
 std::optional<BuildMode> BuildModeFrom(nix::proto::BuildMode mode) {
   switch (mode) {
     case nix::proto::BuildMode::Normal:
diff --git a/third_party/nix/src/libstore/store-api.hh b/third_party/nix/src/libstore/store-api.hh
index b1c0b50de3..39769dfb3c 100644
--- a/third_party/nix/src/libstore/store-api.hh
+++ b/third_party/nix/src/libstore/store-api.hh
@@ -19,6 +19,12 @@
 
 namespace nix {
 
+// Create a no-op stream buffer used to discard build output in cases
+// where we don't have a build log sink to thread through.
+//
+// TODO(tazjin): Get rid of this and do *something* with those logs.
+std::ostream DiscardLogsSink();
+
 MakeError(SubstError, Error);
 MakeError(BuildError, Error); /* denotes a permanent build failure */
 MakeError(InvalidPath, Error);