From 890df325c76a9acd90300bb3590e7d1b102e2c28 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 20 Feb 2020 13:36:16 +0100
Subject: [PATCH] fetchTree: Use a feature flag

---
 src/libexpr/primops/fetchTree.cc | 2 ++
 tests/tarball.sh                 | 8 ++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/libexpr/primops/fetchTree.cc b/src/libexpr/primops/fetchTree.cc
index ccb0cacd5..8fa1f1a11 100644
--- a/src/libexpr/primops/fetchTree.cc
+++ b/src/libexpr/primops/fetchTree.cc
@@ -8,6 +8,8 @@ namespace nix {
 
 static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
+    settings.requireExperimentalFeature("fetch-tree");
+
     std::shared_ptr<const fetchers::Input> input;
     PathSet context;
 
diff --git a/tests/tarball.sh b/tests/tarball.sh
index f43bd6e71..55ed3e318 100644
--- a/tests/tarball.sh
+++ b/tests/tarball.sh
@@ -27,10 +27,10 @@ test_tarball() {
 
     nix-build -o $TEST_ROOT/result -E "import (fetchTarball file://$tarball)"
 
-    nix-build -o $TEST_ROOT/result -E "import (fetchTree file://$tarball)"
-    nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; })"
-    nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })"
-    nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"sha256-xdKv2pq/IiwLSnBBJXW8hNowI4MrdZfW+SYqDQs7Tzc=\"; })" 2>&1 | grep 'NAR hash mismatch in input'
+    nix-build --experimental-features fetch-tree -o $TEST_ROOT/result -E "import (fetchTree file://$tarball)"
+    nix-build --experimental-features fetch-tree -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; })"
+    nix-build --experimental-features fetch-tree -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })"
+    nix-build --experimental-features fetch-tree -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"sha256-xdKv2pq/IiwLSnBBJXW8hNowI4MrdZfW+SYqDQs7Tzc=\"; })" 2>&1 | grep 'NAR hash mismatch in input'
 
     nix-instantiate --eval -E '1 + 2' -I fnord=file://no-such-tarball.tar$ext
     nix-instantiate --eval -E 'with <fnord/xyzzy>; 1 + 2' -I fnord=file://no-such-tarball$ext