libstore: don't abort when flat-importing non-files

fixes #705

Change-Id: I3be20235006425dd3bb6156510d021699f05b9ba

lix/libstore/store-api.cc

@@ -401,12 +401,12 @@ struct RetrieveRegularNARVisitor : NARParseVisitor
 
     box_ptr<NARParseVisitor> createDirectory(const std::string & name) override
     {
-        assert(false && "RetrieveRegularNARVisitor::createDirectory must not be called");
+        throw Error("cannot import directory using flat ingestion");
     }
 
     void createSymlink(const std::string & name, const std::string & target) override
     {
-        assert(false && "RetrieveRegularNARVisitor::createSymlink must not be called");
+        throw Error("cannot import symlink using flat ingestion");
     }
 };
 }

tests/functional/add.sh

@@ -1,5 +1,11 @@
 source common.sh
 
+expectStderr 1 nix-store --add-fixed sha256 . | grep "cannot import directory using flat ingestion"
+expectStderr 1 nix-store --add-fixed sha256 ./symlink | grep "cannot import symlink using flat ingestion"
+
+expectStderr 1 nix-store --add-fixed sha1 . | grep "cannot import directory using flat ingestion"
+expectStderr 1 nix-store --add-fixed sha1 ./symlink | grep "cannot import symlink using flat ingestion"
+
 path1=$(nix-store --add ./dummy)
 echo $path1
 

tests/functional/symlink

@@ -0,0 +1 @@
+add.sh