From 9046d46ba57b8b1232ba2464ae8a0d0200343af9 Mon Sep 17 00:00:00 2001
From: zimbatm <zimbatm@zimbatm.com>
Date: Thu, 26 May 2022 10:15:33 +0200
Subject: [PATCH] import callLocklessFlake

This function was added to nixpkgs in
https://github.com/NixOS/nixpkgs/pull/167947 by MatthewCroughan.
And later reverted because it's for unstable flakes.

So let's add it here, since a lot of projects are already importing
flake-utils.
---
 README.md               | 14 ++++++++++++++
 call-lockless-flake.nix | 16 ++++++++++++++++
 default.nix             |  2 ++
 3 files changed, 32 insertions(+)
 create mode 100644 call-lockless-flake.nix

diff --git a/README.md b/README.md
index a1b43f6..81e6df9 100644
--- a/README.md
+++ b/README.md
@@ -144,6 +144,20 @@ Input:
 }: null
 ```
 
+### `callLocklessFlake -> { path, inputs ? { } } -> attrs`
+
+Imports a flake.nix without acknowledging its lock file, useful for
+referencing subflakes from a parent flake. The second argument allows
+specifying the inputs of this flake.
+
+Example:
+```
+callLocklessFlake {
+  path = ./directoryContainingFlake;
+  inputs = { inherit nixpkgs; };
+}
+```
+
 #### Example
 
 Here is how it looks like in practice:
diff --git a/call-lockless-flake.nix b/call-lockless-flake.nix
new file mode 100644
index 0000000..93a76ea
--- /dev/null
+++ b/call-lockless-flake.nix
@@ -0,0 +1,16 @@
+/*
+  Imports a flake.nix without acknowledging its lock file, useful for
+  referencing subflakes from a parent flake. The second argument allows
+  specifying the inputs of this flake.
+  Example:
+    callLocklessFlake {
+      path = ./directoryContainingFlake;
+      inputs = { inherit nixpkgs; };
+    }
+*/
+{ path, inputs ? { } }:
+let
+  self = { outPath = path; } //
+    ((import (path + "/flake.nix")).outputs (inputs // { self = self; }));
+in
+self
diff --git a/default.nix b/default.nix
index 8c2c729..9735284 100644
--- a/default.nix
+++ b/default.nix
@@ -192,6 +192,8 @@ let
   #   }
   filterPackages = import ./filterPackages.nix { inherit allSystems; };
 
+  callLocklessFlake = import ./call-lockless-flake.nix;
+
   # Returns the structure used by `nix app`
   mkApp =
     { drv