From 78a66fe898d8d4b4286e45e831dcd87f1e9b21ba Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Giraudeau <jean-baptiste.giraudeau@iohk.io>
Date: Thu, 17 Mar 2022 16:54:20 +0100
Subject: [PATCH] flake-compat: use builtins.fetchTree if available

---
 flake.lock           |  6 +++---
 nix/flake-compat.nix | 17 +++++++----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/flake.lock b/flake.lock
index 1977e693049..f4f87eca5eb 100644
--- a/flake.lock
+++ b/flake.lock
@@ -496,11 +496,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1638445031,
-        "narHash": "sha256-dtIZLlf2tfYeLvpZa/jFxP5HvfoXAzr7X76yn6FQAdM=",
+        "lastModified": 1647532380,
+        "narHash": "sha256-wswAxyO8AJTH7d5oU8VK82yBCpqwA+p6kLgpb1f1PAY=",
         "owner": "input-output-hk",
         "repo": "flake-compat",
-        "rev": "20f79e3976b76a37090fbeec7b49dc08dac96b8e",
+        "rev": "7da118186435255a30b5ffeabba9629c344c0bec",
         "type": "github"
       },
       "original": {
diff --git a/nix/flake-compat.nix b/nix/flake-compat.nix
index 47ec2b7ed71..e62cfa47e55 100644
--- a/nix/flake-compat.nix
+++ b/nix/flake-compat.nix
@@ -4,16 +4,13 @@ let
   lock = builtins.fromJSON (builtins.readFile (src + "/flake.lock"));
   flake-compate-input = lock.nodes.root.inputs.flake-compat;
   nixpkgs-input = lock.nodes.haskellNix.inputs.${builtins.elemAt lock.nodes.root.inputs.nixpkgs 1};
-  flake-compat = import (builtins.fetchTarball {
-    url = "https://api.github.com/repos/input-output-hk/flake-compat/tarball/${lock.nodes.${flake-compate-input}.locked.rev}";
-    sha256 = lock.nodes.${flake-compate-input}.locked.narHash;
-  });
-  pkgs = import
-    (builtins.fetchTarball {
-      url = "https://api.github.com/repos/NixOS/nixpkgs/tarball/${lock.nodes.${nixpkgs-input}.locked.rev}";
-      sha256 = lock.nodes.${nixpkgs-input}.locked.narHash;
-    })
-    { };
+  fetchTree = builtins.fetchTree or (info:
+    builtins.fetchTarball {
+      url = "https://api.github.com/repos/${info.owner}/${info.repo}/tarball/${info.rev}";
+      sha256 = info.narHash;
+    });
+  flake-compat = import (fetchTree lock.nodes.${flake-compate-input}.locked);
+  pkgs = import (fetchTree lock.nodes.${nixpkgs-input}.locked) { };
 in
 flake-compat {
   inherit src pkgs;