From da1ad28912334bb57f923afb4745273fd68f695c Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 5 Sep 2024 16:48:43 +0200
Subject: [PATCH] Test that nix-store --restore fails if the output already
 exists

This restores the behaviour from before the std::filesystem
refactorings.
---
 src/libutil/fs-sink.cc   | 3 ++-
 tests/functional/nars.sh | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/libutil/fs-sink.cc b/src/libutil/fs-sink.cc
index 154346cee..b1e342c77 100644
--- a/src/libutil/fs-sink.cc
+++ b/src/libutil/fs-sink.cc
@@ -71,7 +71,8 @@ static GlobalConfig::Register r1(&restoreSinkSettings);
 
 void RestoreSink::createDirectory(const CanonPath & path)
 {
-    std::filesystem::create_directory(dstPath / path.rel());
+    if (!std::filesystem::create_directory(dstPath / path.rel()))
+        throw Error("path '%s' already exists", (dstPath / path.rel()).string());
 };
 
 struct RestoreRegularFile : CreateRegularFileSink {
diff --git a/tests/functional/nars.sh b/tests/functional/nars.sh
index c58d12cd5..106bd10fc 100755
--- a/tests/functional/nars.sh
+++ b/tests/functional/nars.sh
@@ -10,6 +10,9 @@ clearStore
 rm -rf "$TEST_ROOT/out"
 expectStderr 1 nix-store --restore "$TEST_ROOT/out" < duplicate.nar | grepQuiet "NAR directory is not sorted"
 
+# Check that nix-store --restore fails if the output already exists.
+expectStderr 1 nix-store --restore "$TEST_ROOT/out" < duplicate.nar | grepQuiet "path '.*/out/' already exists"
+
 # Check whether restoring and dumping a NAR that contains case
 # collisions is round-tripping, even on a case-insensitive system.
 rm -rf "$TEST_ROOT/case"