From f902f3c2cbfa1a78bec8d135297abe244452e794 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 24 Mar 2022 21:33:20 +0100
Subject: [PATCH] Add experimental feature 'fetch-closure'

---
 src/libexpr/primops/fetchClosure.cc  | 2 ++
 src/libutil/experimental-features.cc | 1 +
 src/libutil/experimental-features.hh | 3 ++-
 tests/fetchClosure.sh                | 1 +
 4 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/libexpr/primops/fetchClosure.cc b/src/libexpr/primops/fetchClosure.cc
index 3e07d1d18e4..47f40ef33ed 100644
--- a/src/libexpr/primops/fetchClosure.cc
+++ b/src/libexpr/primops/fetchClosure.cc
@@ -7,6 +7,8 @@ namespace nix {
 
 static void prim_fetchClosure(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
+    settings.requireExperimentalFeature(Xp::FetchClosure);
+
     state.forceAttrs(*args[0], pos);
 
     std::optional<std::string> fromStoreUrl;
diff --git a/src/libutil/experimental-features.cc b/src/libutil/experimental-features.cc
index b49f47e1d45..01f318fa396 100644
--- a/src/libutil/experimental-features.cc
+++ b/src/libutil/experimental-features.cc
@@ -11,6 +11,7 @@ std::map<ExperimentalFeature, std::string> stringifiedXpFeatures = {
     { Xp::NixCommand, "nix-command" },
     { Xp::RecursiveNix, "recursive-nix" },
     { Xp::NoUrlLiterals, "no-url-literals" },
+    { Xp::FetchClosure, "fetch-closure" },
 };
 
 const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name)
diff --git a/src/libutil/experimental-features.hh b/src/libutil/experimental-features.hh
index 291a58e32dd..b5140dcfea8 100644
--- a/src/libutil/experimental-features.hh
+++ b/src/libutil/experimental-features.hh
@@ -19,7 +19,8 @@ enum struct ExperimentalFeature
     Flakes,
     NixCommand,
     RecursiveNix,
-    NoUrlLiterals
+    NoUrlLiterals,
+    FetchClosure,
 };
 
 /**
diff --git a/tests/fetchClosure.sh b/tests/fetchClosure.sh
index 811d44af9ac..0c905ac43f8 100644
--- a/tests/fetchClosure.sh
+++ b/tests/fetchClosure.sh
@@ -1,5 +1,6 @@
 source common.sh
 
+enableFeatures "fetch-closure"
 needLocalStore "'--no-require-sigs' can’t be used with the daemon"
 
 clearStore