From f6dbde71815da3afa854858ab07c28462edcdd4c Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Fri, 7 Nov 2025 17:53:52 +0100
Subject: [PATCH 1/8] Import fileFilter directly instead of via overlay

---
 libs/opsqueue_python/opsqueue_python.nix | 10 +++--
 nix/overlay.nix                          | 46 -----------------------
 nix/util.nix                             | 48 ++++++++++++++++++++++++
 opsqueue/opsqueue.nix                    |  9 +++--
 4 files changed, 61 insertions(+), 52 deletions(-)
 create mode 100644 nix/util.nix

diff --git a/libs/opsqueue_python/opsqueue_python.nix b/libs/opsqueue_python/opsqueue_python.nix
index f024ec1..d392480 100644
--- a/libs/opsqueue_python/opsqueue_python.nix
+++ b/libs/opsqueue_python/opsqueue_python.nix
@@ -1,5 +1,5 @@
 {
-  fileFilter,
+  lib,
   buildPythonPackage,
   rustPlatform,
   perl,
@@ -10,14 +10,18 @@
   opentelemetry-exporter-otlp,
   opentelemetry-sdk,
 }:
+let
+  root = ../../.;
+  util = import (root + /nix/util.nix) { inherit lib; };
+in
 buildPythonPackage rec {
   pname = "opsqueue";
   version = "0.1.0";
   pyproject = true;
 
-  src = fileFilter {
+  src = util.fileFilter {
     name = "opsqueue_python";
-    src = ../../.;
+    src = root;
 
     # We're copying slightly too much to the Nix store here,
     # but using the more granular file filter was very error-prone.
diff --git a/nix/overlay.nix b/nix/overlay.nix
index 25334e8..ddfd3e0 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -5,55 +5,9 @@
 self: super:
 let
   sources = import ./sources.nix;
-  lib = super.pkgs.lib;
   pythonOverlay = import ./python-overlay.nix { inherit sources; };
 in
 {
-  # A powerful way of filtering the right files for the src attribute of a derivation.
-  fileFilter =
-    {
-      name,
-      # Regex whitelist of files
-      srcWhitelist ? [ ".*" ],
-      # Blacklist of files and directories anywhere in the repository. Use only
-      # with files that can appear in multiple places in the repository.
-      srcGlobalBlacklist ? [ ],
-      # Global whitelist by suffix, only allow the following file extensions
-      srcGlobalWhitelist ? [ ],
-      # Global whitelist by regex, only allow the following file extensions
-      srcGlobalWhitelistRegex ? [ ],
-      src,
-    }:
-    lib.cleanSourceWith rec {
-      inherit name src;
-      filter =
-        path: type:
-        let
-          relativePath = lib.removePrefix (toString src + "/") path;
-        in
-        (builtins.any (r: builtins.match r relativePath != null) srcWhitelist)
-        &&
-          # Whitelist these files
-          (
-            (type == "directory")
-            || (
-              (builtins.length srcGlobalWhitelist != 0)
-              && (builtins.any (suffix: lib.hasSuffix suffix relativePath) srcGlobalWhitelist)
-              || (
-                (builtins.length srcGlobalWhitelistRegex != 0)
-                && (builtins.any (r: builtins.match r relativePath != null) srcGlobalWhitelistRegex)
-              )
-            )
-          )
-        &&
-          # Ignore the files from srcGlobalBlacklist anywhere
-          !(builtins.elem (baseNameOf path) srcGlobalBlacklist)
-        &&
-          # Discard editor files, git repo stuff, and other cruft. This one is taken
-          # from Nixpkgs; we don't need to implement it ourselves.
-          lib.cleanSourceFilter path type;
-    };
-
   # Placing the sources in the overlay gives all packages access to the sources,
   # and it makes it possible to override them in new overlays.
   sources = if super ? sources then super.sources // sources else sources;
diff --git a/nix/util.nix b/nix/util.nix
new file mode 100644
index 0000000..fd17252
--- /dev/null
+++ b/nix/util.nix
@@ -0,0 +1,48 @@
+# Utility functions to use in nix code
+{ lib }:
+{
+  # A powerful way of filtering the right files for the src attribute of a derivation.
+  fileFilter =
+    {
+      name,
+      # Regex whitelist of files
+      srcWhitelist ? [ ".*" ],
+      # Blacklist of files and directories anywhere in the repository. Use only
+      # with files that can appear in multiple places in the repository.
+      srcGlobalBlacklist ? [ ],
+      # Global whitelist by suffix, only allow the following file extensions
+      srcGlobalWhitelist ? [ ],
+      # Global whitelist by regex, only allow the following file extensions
+      srcGlobalWhitelistRegex ? [ ],
+      src,
+    }:
+    lib.cleanSourceWith rec {
+      inherit name src;
+      filter =
+        path: type:
+        let
+          relativePath = lib.removePrefix (toString src + "/") path;
+        in
+        (builtins.any (r: builtins.match r relativePath != null) srcWhitelist)
+        &&
+          # Whitelist these files
+          (
+            (type == "directory")
+            || (
+              (builtins.length srcGlobalWhitelist != 0)
+              && (builtins.any (suffix: lib.hasSuffix suffix relativePath) srcGlobalWhitelist)
+              || (
+                (builtins.length srcGlobalWhitelistRegex != 0)
+                && (builtins.any (r: builtins.match r relativePath != null) srcGlobalWhitelistRegex)
+              )
+            )
+          )
+        &&
+          # Ignore the files from srcGlobalBlacklist anywhere
+          !(builtins.elem (baseNameOf path) srcGlobalBlacklist)
+        &&
+          # Discard editor files, git repo stuff, and other cruft. This one is taken
+          # from Nixpkgs; we don't need to implement it ourselves.
+          lib.cleanSourceFilter path type;
+    };
+}
diff --git a/opsqueue/opsqueue.nix b/opsqueue/opsqueue.nix
index 53c0aed..267907a 100644
--- a/opsqueue/opsqueue.nix
+++ b/opsqueue/opsqueue.nix
@@ -1,6 +1,5 @@
 {
-  fileFilter,
-  pkgs,
+  lib,
   rustPlatform,
   # Building options
   buildType ? "release",
@@ -11,6 +10,10 @@
   perl,
   git,
 }:
+let
+  root = ../.;
+  util = import (root + /nix/util.nix) { inherit lib; };
+in
 rustPlatform.buildRustPackage {
   name = "opsqueue";
   inherit
@@ -20,7 +23,7 @@ rustPlatform.buildRustPackage {
     useNextest
     ;
 
-  src = fileFilter {
+  src = util.fileFilter {
     name = "opsqueue";
     src = ./.;
 

From aaaddcffa73dd2941dda4098f13d34fde53ce11e Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Thu, 6 Nov 2025 18:29:37 +0100
Subject: [PATCH 2/8] Fix comment referring to a private repo

---
 nix/overlay.nix | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/nix/overlay.nix b/nix/overlay.nix
index ddfd3e0..293bcdb 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -1,7 +1,4 @@
-# Overlay for Nixpkgs which holds rust-jobs related packages.
-#
-# Serves as common overlay for this repository.
-#
+# Overlay for Nixpkgs which holds all opsqueue related packages.
 self: super:
 let
   sources = import ./sources.nix;

From 98d9cdbc1837800435edee27471e5ed8c56dc71b Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Thu, 6 Nov 2025 18:46:06 +0100
Subject: [PATCH 3/8] Remove special pre-commit setup

Everything in there ultimately relies on Channable-internal tooling, and is only needed if
we want to run pre-commit in a separate environment. For this repo it's okay to just put
pre-commit and tools we want to run through it in the same `mkShell`.
---
 .pre-commit-config.yaml |  1 -
 default.nix             |  6 +++++-
 nix/overlay.nix         | 11 -----------
 pre-commit/.envrc       | 17 -----------------
 pre-commit/README.md    | 14 --------------
 pre-commit/default.nix  | 13 -------------
 6 files changed, 5 insertions(+), 57 deletions(-)
 delete mode 100644 pre-commit/.envrc
 delete mode 100644 pre-commit/README.md
 delete mode 100644 pre-commit/default.nix

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 03fe6e4..3c136ce 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,4 +1,3 @@
-# Pre-commit config as used by ./build.py.
 repos:
   # Use local to make sure the dependencies are taken from pre-commit's own environment and
   # therefore from our nix derivation.
diff --git a/default.nix b/default.nix
index 3815d8e..a581bcb 100644
--- a/default.nix
+++ b/default.nix
@@ -29,8 +29,12 @@ let
       just
 
       # For linting and formatting
+      biome
+      nixfmt-rfc-style
       pre-commit
-      pre-commit-env
+      python3Packages.pre-commit-hooks
+      ruff
+      rust-with-lsp
 
       # For compiling the Rust parts
       rust-with-lsp
diff --git a/nix/overlay.nix b/nix/overlay.nix
index 293bcdb..c2c5d84 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -25,15 +25,4 @@ in
       "rustfmt"
     ];
   };
-
-  pre-commit-env = self.buildEnv {
-    name = "pre-commit-env";
-    paths = [
-      super.python3Packages.pre-commit-hooks
-      super.nixfmt-rfc-style
-      super.ruff
-      super.biome
-      self.rust-with-lsp
-    ];
-  };
 }
diff --git a/pre-commit/.envrc b/pre-commit/.envrc
deleted file mode 100644
index cab5f86..0000000
--- a/pre-commit/.envrc
+++ /dev/null
@@ -1,17 +0,0 @@
-# shellcheck disable=SC2148 # .envrc files need no shell directive
-shopt -s dotglob globstar
-
-# Decrease logging output
-# shellcheck disable=SC2034 # unused variable is still read by direnv.
-DIRENV_LOG_FORMAT=
-# Install nix-direnv, which has an improved implementation of `use nix` that
-# caches the Nix environment. Note that this URL is cached locally, so it
-# doesn't fetch the script every time.
-if ! has nix_direnv_version || ! nix_direnv_version 3.0.4; then
-  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.4/direnvrc" "sha256-DzlYZ33mWF/Gs8DDeyjr8mnVmQGx7ASYqA5WlxwvBG4="
-fi
-
-nix_direnv_watch_file ../nix/**/*.nix ../nix/sources.json
-
-
-use nix default.nix
diff --git a/pre-commit/README.md b/pre-commit/README.md
deleted file mode 100644
index a6c9b46..0000000
--- a/pre-commit/README.md
+++ /dev/null
@@ -1,14 +0,0 @@
-# pre-commit
-
-This folder exists to massage [pre-commit] to work with Nix and direnv. Our pre-commit setup works
-as follows:
-
-- We install a custom pre-commit hook with the `build.py install pre-commit` command;
-- This hook uses `direnv` to cache pre-commit (the tool) and it's dependencies. This in order to
-  keep the dependencies up to date automatically but still keep the hook fast;
-- Those dependencies are declared in a separate Nix file (`default.nix` in this folder). We use a
-  separate Nix file to minimize the dependencies, which means direnv has to reload less often.
-- We need a separate `.envrc` file, located in this folder, as one can not specify a file to the
-  `direnv exec` command, only a folder.
-
- [pre-commit]: https://pre-commit.com/
diff --git a/pre-commit/default.nix b/pre-commit/default.nix
deleted file mode 100644
index feff433..0000000
--- a/pre-commit/default.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-let
-  pkgs = import ../nix/nixpkgs-pinned.nix { };
-
-  defaultEnv = pkgs.buildEnv {
-    name = "pre-commit-env";
-    paths = with pkgs; [
-      # Used to execute the pre-commit hook
-      pre-commit
-      pre-commit-env
-    ];
-  };
-in
-pkgs.mkShell { packages = [ defaultEnv ]; }

From 1795986455a4db5a9eacb86135850d1d969323fc Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Thu, 6 Nov 2025 18:44:24 +0100
Subject: [PATCH 4/8] Use the final-prev convention for overlays instead of
 self-super

---
 nix/overlay.nix        | 10 +++++-----
 nix/python-overlay.nix |  4 +++-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/nix/overlay.nix b/nix/overlay.nix
index c2c5d84..c7c08e7 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -1,5 +1,5 @@
 # Overlay for Nixpkgs which holds all opsqueue related packages.
-self: super:
+final: prev:
 let
   sources = import ./sources.nix;
   pythonOverlay = import ./python-overlay.nix { inherit sources; };
@@ -7,19 +7,19 @@ in
 {
   # Placing the sources in the overlay gives all packages access to the sources,
   # and it makes it possible to override them in new overlays.
-  sources = if super ? sources then super.sources // sources else sources;
+  sources = if prev ? sources then prev.sources // sources else sources;
 
-  opsqueue = self.callPackage ../opsqueue/opsqueue.nix { };
+  opsqueue = final.callPackage ../opsqueue/opsqueue.nix { };
 
   # The explicit choice is made not to override `python312`, as this will cause a rebuild of many
   # packages when nixpkgs uses python 3.12 as default python environment.
   # These packages should not be affected, e.g. cachix. This is because of a transitive
   # dependency on the Python packages that we override.
   # In our case cachix > ghc > shpinx > Python libraries.
-  pythonChannable = super.python312.override { packageOverrides = pythonOverlay; };
+  pythonChannable = prev.python312.override { packageOverrides = pythonOverlay; };
 
   # We choose a minimal Rust channel to keep the Nix closure size smaller
-  rust-with-lsp = self.rust-bin.stable.latest.minimal.override {
+  rust-with-lsp = final.rust-bin.stable.latest.minimal.override {
     extensions = [
       "clippy"
       "rustfmt"
diff --git a/nix/python-overlay.nix b/nix/python-overlay.nix
index 6c737da..9e46acb 100644
--- a/nix/python-overlay.nix
+++ b/nix/python-overlay.nix
@@ -1,4 +1,6 @@
 {
   sources ? import ./sources.nix,
 }:
-self: super: { opsqueue_python = self.callPackage ../libs/opsqueue_python/opsqueue_python.nix { }; }
+final: prev: {
+  opsqueue_python = final.callPackage ../libs/opsqueue_python/opsqueue_python.nix { };
+}

From 08904fd0a0d308370929abb96ce1ceadecbe9932 Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Fri, 7 Nov 2025 17:18:38 +0100
Subject: [PATCH 5/8] Move Rust devshell code out of the nixpkgs overlay

---
 default.nix     | 39 +++++++++++++++++++++++----------------
 nix/overlay.nix |  7 -------
 2 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/default.nix b/default.nix
index a581bcb..ce38ff7 100644
--- a/default.nix
+++ b/default.nix
@@ -22,33 +22,40 @@ let
     ]
   );
 
+  # We choose a minimal Rust channel to keep the Nix closure size smaller
+  rust = pkgs.rust-bin.stable.latest.minimal.override {
+    extensions = [
+      "clippy"
+      "rustfmt"
+    ];
+  };
+
   defaultEnv = pkgs.buildEnv {
     name = "opsqueue-env-default";
-    paths = with pkgs; [
+    paths = [
       # Command runner
-      just
+      pkgs.just
 
       # For linting and formatting
-      biome
-      nixfmt-rfc-style
-      pre-commit
-      python3Packages.pre-commit-hooks
-      ruff
-      rust-with-lsp
+      pkgs.biome
+      pkgs.nixfmt-rfc-style
+      pkgs.pre-commit
+      pkgs.python3Packages.pre-commit-hooks
+      pkgs.ruff
 
       # For compiling the Rust parts
-      rust-with-lsp
-      sqlx-cli
+      rust
+      pkgs.sqlx-cli
 
       # Manage nix pins
-      niv
-      nvd
+      pkgs.niv
+      pkgs.nvd
 
       # Rust build tools
-      cargo-audit
-      cargo-edit
-      cargo-nextest
-      maturin
+      pkgs.cargo-audit
+      pkgs.cargo-edit
+      pkgs.cargo-nextest
+      pkgs.maturin
     ];
   };
   environments = {
diff --git a/nix/overlay.nix b/nix/overlay.nix
index c7c08e7..c28ba8a 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -18,11 +18,4 @@ in
   # In our case cachix > ghc > shpinx > Python libraries.
   pythonChannable = prev.python312.override { packageOverrides = pythonOverlay; };
 
-  # We choose a minimal Rust channel to keep the Nix closure size smaller
-  rust-with-lsp = final.rust-bin.stable.latest.minimal.override {
-    extensions = [
-      "clippy"
-      "rustfmt"
-    ];
-  };
 }

From 20867fdff6f7e9ecef6548b1a2d2bbd586e58f9f Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Fri, 7 Nov 2025 17:30:39 +0100
Subject: [PATCH 6/8] Remove unnecessary passing around of sources

---
 nix/overlay.nix        | 7 +------
 nix/python-overlay.nix | 3 ---
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/nix/overlay.nix b/nix/overlay.nix
index c28ba8a..3f8c455 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -1,14 +1,9 @@
 # Overlay for Nixpkgs which holds all opsqueue related packages.
 final: prev:
 let
-  sources = import ./sources.nix;
-  pythonOverlay = import ./python-overlay.nix { inherit sources; };
+  pythonOverlay = import ./python-overlay.nix;
 in
 {
-  # Placing the sources in the overlay gives all packages access to the sources,
-  # and it makes it possible to override them in new overlays.
-  sources = if prev ? sources then prev.sources // sources else sources;
-
   opsqueue = final.callPackage ../opsqueue/opsqueue.nix { };
 
   # The explicit choice is made not to override `python312`, as this will cause a rebuild of many
diff --git a/nix/python-overlay.nix b/nix/python-overlay.nix
index 9e46acb..ad4aba1 100644
--- a/nix/python-overlay.nix
+++ b/nix/python-overlay.nix
@@ -1,6 +1,3 @@
-{
-  sources ? import ./sources.nix,
-}:
 final: prev: {
   opsqueue_python = final.callPackage ../libs/opsqueue_python/opsqueue_python.nix { };
 }

From 07e2adb5145c2c8e9ef2230cca6a32d890491e19 Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Fri, 7 Nov 2025 17:59:06 +0100
Subject: [PATCH 7/8] Simplify .envrc

---
 .envrc | 31 ++++++++++---------------------
 1 file changed, 10 insertions(+), 21 deletions(-)

diff --git a/.envrc b/.envrc
index 78eaec2..6fce732 100644
--- a/.envrc
+++ b/.envrc
@@ -1,27 +1,16 @@
 # shellcheck disable=SC2148 # .envrc files need no shell directive
 shopt -s dotglob globstar
 
-# NOTE: This file is based on https://github.com/channable/repository-template/blob/master/.envrc
-# When making edits that apply to other repositories, please update the file there.
-
-# Add possibility to run a custom envrc that completely overrides the behavior of this envrc.
-CUSTOM_ENVRC=.customenvrc
-if [ -f "$CUSTOM_ENVRC" ]; then
-  echo "Using .customenvrc file"
-  source_env $CUSTOM_ENVRC
-else
-  # Decrease logging output
-  # shellcheck disable=SC2034 # unused variable is still read by direnv.
-  DIRENV_LOG_FORMAT=
-  # Install nix-direnv, which has an improved implementation of `use nix` that
-  # caches the Nix environment. Note that this URL is cached locally, so it
-  # doesn't fetch the script every time.
-  if ! has nix_direnv_version || ! nix_direnv_version 3.0.4; then
+# Decrease logging output
+# shellcheck disable=SC2034 # unused variable is still read by direnv.
+DIRENV_LOG_FORMAT=
+# Install nix-direnv, which has an improved implementation of `use nix` that
+# caches the Nix environment. Note that this URL is cached locally, so it
+# doesn't fetch the script every time.
+if ! has nix_direnv_version || ! nix_direnv_version 3.0.4; then
     source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.4/direnvrc" "sha256-DzlYZ33mWF/Gs8DDeyjr8mnVmQGx7ASYqA5WlxwvBG4="
-  fi
-
-  watch_file  nix/sources.json nix/sources.nix nix/overlay.nix nix/python-overlay.nix opsqueue/opsqueue.nix /libs/opsqueue_python/opsqueue_python.nix
+fi
 
+watch_file ./nix/ ./**/*.nix
 
-  use nix default.nix --argstr environment shell
-fi
+use nix default.nix --argstr environment shell

From 30ba761d62d42c3fd21e76076f786fcaf8b3667d Mon Sep 17 00:00:00 2001
From: Daan Rijks <daan.rijks@channable.com>
Date: Fri, 7 Nov 2025 18:00:02 +0100
Subject: [PATCH 8/8] Remove vendored Nix install script

No way that'll actually be kept up to date.
---
 nix/install | 94 -----------------------------------------------------
 1 file changed, 94 deletions(-)
 delete mode 100755 nix/install

diff --git a/nix/install b/nix/install
deleted file mode 100755
index c3cf49d..0000000
--- a/nix/install
+++ /dev/null
@@ -1,94 +0,0 @@
-#!/bin/sh
-
-# Vendored Nix installation script.
-# Retrieved 2023-05-01 from https://nixos.org/nix/install
-# Updated curl call to include 3 retries.
-# Removed hashes for unsupported systems.
-
-# This script installs the Nix package manager on your system by
-# downloading a binary distribution and running its installer script
-# (which in turn creates and populates /nix).
-
-{ # Prevent execution if this script was only partially downloaded
-oops() {
-    echo "$0:" "$@" >&2
-    exit 1
-}
-
-umask 0022
-
-tmpDir="$(mktemp -d -t nix-binary-tarball-unpack.XXXXXXXXXX || \
-          oops "Can't create temporary directory for downloading the Nix binary tarball")"
-cleanup() {
-    rm -rf "$tmpDir"
-}
-trap cleanup EXIT INT QUIT TERM
-
-require_util() {
-    command -v "$1" > /dev/null 2>&1 ||
-        oops "you do not have '$1' installed, which I need to $2"
-}
-
-case "$(uname -s).$(uname -m)" in
-    Linux.x86_64)
-        hash=1bdf98f951ce82ad1a12b9e6874f5858cb2aa2e402907e8c3079d8482cb8430b
-        path=dw0gkcqnig9qwyhkrq0sjrzai63zi6wy/nix-2.15.0-x86_64-linux.tar.xz
-        system=x86_64-linux
-        ;;
-    *) oops "sorry, there is no binary distribution of Nix for your platform";;
-esac
-
-# Use this command-line option to fetch the tarballs using nar-serve or Cachix
-if [ "${1:-}" = "--tarball-url-prefix" ]; then
-    if [ -z "${2:-}" ]; then
-        oops "missing argument for --tarball-url-prefix"
-    fi
-    url=${2}/${path}
-    shift 2
-else
-    url=https://releases.nixos.org/nix/nix-2.15.0/nix-2.15.0-$system.tar.xz
-fi
-
-tarball=$tmpDir/nix-2.15.0-$system.tar.xz
-
-require_util tar "unpack the binary tarball"
-if [ "$(uname -s)" != "Darwin" ]; then
-    require_util xz "unpack the binary tarball"
-fi
-
-if command -v curl --retry 3 > /dev/null 2>&1; then
-    fetch() { curl --fail -L "$1" -o "$2"; }
-elif command -v wget > /dev/null 2>&1; then
-    fetch() { wget "$1" -O "$2"; }
-else
-    oops "you don't have wget or curl installed, which I need to download the binary tarball"
-fi
-
-echo "downloading Nix 2.15.0 binary tarball for $system from '$url' to '$tmpDir'..."
-fetch "$url" "$tarball" || oops "failed to download '$url'"
-
-if command -v sha256sum > /dev/null 2>&1; then
-    hash2="$(sha256sum -b "$tarball" | cut -c1-64)"
-elif command -v shasum > /dev/null 2>&1; then
-    hash2="$(shasum -a 256 -b "$tarball" | cut -c1-64)"
-elif command -v openssl > /dev/null 2>&1; then
-    hash2="$(openssl dgst -r -sha256 "$tarball" | cut -c1-64)"
-else
-    oops "cannot verify the SHA-256 hash of '$url'; you need one of 'shasum', 'sha256sum', or 'openssl'"
-fi
-
-if [ "$hash" != "$hash2" ]; then
-    oops "SHA-256 hash mismatch in '$url'; expected $hash, got $hash2"
-fi
-
-unpack=$tmpDir/unpack
-mkdir -p "$unpack"
-tar -xJf "$tarball" -C "$unpack" || oops "failed to unpack '$url'"
-
-script=$(echo "$unpack"/*/install)
-
-[ -e "$script" ] || oops "installation script is missing from the binary tarball!"
-export INVOKED_FROM_INSTALL_IN=1
-"$script" "$@"
-
-} # End of wrapping