nix: Backport bug fix to check NAR integrity

pkgs/tools/package-management/nix/default.nix

@@ -12,6 +12,8 @@ stdenv.mkDerivation rec {
     sha256 = "31d15f99b2405924a4be278334cc973a71999303631e6798c1d294db9be4bf84";
   };
 
+  patches = [ ./hash-check.patch ];
+
   nativeBuildInputs = [ perl pkgconfig ];
 
   buildInputs = [ curl openssl boehmgc sqlite ];

pkgs/tools/package-management/nix/hash-check.patch

@@ -0,0 +1,14 @@
+commit 11cb4bfb257f18c906ef1d6f14ed450be8fa49fe upstream
+
+diff --git a/src/libstore/build.cc b/src/libstore/build.cc
+index dcd7343..4329d9a 100644
+--- a/src/libstore/build.cc
++++ b/src/libstore/build.cc
+@@ -2749,6 +2749,7 @@ void SubstitutionGoal::finished()
+     logPipe.readSide.close();
+ 
+     /* Get the hash info from stdout. */
++    string dummy = readLine(outPipe.readSide);
+     string expectedHashStr = statusOk(status) ? readLine(outPipe.readSide) : "";
+     outPipe.readSide.close();
+