nix-store --export: Export paths in topologically sorted order

Fixes #118.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index 151ed97e4b8b..5bd8558361df 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -694,7 +694,9 @@ static void opExport(Strings opFlags, Strings opArgs)
         else throw UsageError(format("unknown flag `%1%'") % *i);
 
     FdSink sink(STDOUT_FILENO);
-    exportPaths(*store, opArgs, sign, sink);
+    Paths sorted = topoSortPaths(*store, PathSet(opArgs.begin(), opArgs.end()));
+    reverse(sorted.begin(), sorted.end());
+    exportPaths(*store, sorted, sign, sink);
 }