minimal-bootstrap: use recursive FOD to make nix unpack bootstrap sources

pkgs/os-specific/linux/minimal-bootstrap/stage0-posix/bootstrap-sources.nix

@@ -7,6 +7,7 @@ rec {
   version = "unstable-2023-05-02";
   rev = "3189b5f325b7ef8b88e3edec7c1cde4fce73c76c";
   outputHashAlgo = "sha256";
+  outputHash = "sha256-FpMp7z+B3cR3LkQ+PooH/b1/NlxH8NHVJNWifaPWt4U=";
 
   # This 256 byte seed is the only pre-compiled binary in the bootstrap chain.
   hex0-seed = import <nix/fetchurl.nix> {
@@ -29,7 +30,7 @@ rec {
 
   Run the following command:
   ```
-  nix hash file $(nix build --print-out-paths -f '<nixpkgs>' make-minimal-bootstrap-sources)
+  nix hash path $(nix build --print-out-paths -f '<nixpkgs>' make-minimal-bootstrap-sources)
   ```
 
   # Why do we need this `.nar` archive?
@@ -71,11 +72,10 @@ rec {
   requirements above apply to `minimal-bootstrap-sources`.
   */
   minimal-bootstrap-sources = derivation {
-    name = "${name}.nar.xz";
+    inherit name;
     system = builtins.currentSystem;
-    outputHashMode = "flat";
-    inherit outputHashAlgo;
-    outputHash = "sha256-ig988BiRTz92hhZZgKQW1tVPoV4aQ2D69Cq3wHvVgHg=";
+    outputHashMode = "recursive";
+    inherit outputHashAlgo outputHash;
 
     # This builder always fails, but fortunately Nix will print the
     # "builder", which is really the error message that we want the
@@ -85,22 +85,21 @@ rec {
       #
       # Neither your store nor your substituters seems to have:
       #
-      #  ${name}.nar.xz
+      #  ${builtins.placeholder "out"}
       #
-      # Please obtain or create this file, give it exactly the name
-      # shown above, and then run the following command:
-      #
-      #   nix-store --add-fixed ${outputHashAlgo} ${name}.nar.xz
-      #
-      # You can create this file from an already-bootstrapped nixpkgs
+      # You can create this path from an already-bootstrapped nixpkgs
       # using the following command:
       #
       #   nix-build '<nixpkgs>' -A make-minimal-bootstrap-sources
       #
       # Or, if you prefer, you can create this file using only `git`,
       # `nix`, and `xz`.  For the commands needed in order to do this,
-      # see `make-bootstrap-sources.nix`.
+      # see `make-bootstrap-sources.nix`.  Once you have the manual
+      # result, do:
+      #
+      #   nix-store --add-fixed --recursive ${outputHashAlgo} ./${name}
       #
+      # to add it to your store.
     '';
   };
 }

pkgs/os-specific/linux/minimal-bootstrap/stage0-posix/make-bootstrap-sources.nix

@@ -8,44 +8,36 @@
 #
 # To build:
 #
-#   nix-build '<nixpkgs>' -o sources.nar.xz -A make-minimal-bootstrap-sources
+#   nix-build '<nixpkgs>' -A make-minimal-bootstrap-sources
 #
 
 { lib
 , fetchFromGitHub
-, runCommand
-, nix
-, xz
 }:
-let
-  inherit (import ./bootstrap-sources.nix { }) name rev;
-
-  src = fetchFromGitHub {
-    owner = "oriansj";
-    repo = "stage0-posix";
-    inherit rev;
-    sha256 = "sha256-FpMp7z+B3cR3LkQ+PooH/b1/NlxH8NHVJNWifaPWt4U=";
-    fetchSubmodules = true;
-    postFetch = ''
-      # Seed binaries will be fetched separately
-      echo "Removing seed binaries"
-      rm -rf $out/bootstrap-seeds/*
-
-      # Remove vendored/duplicate M2libc's
-      echo "Removing duplicate M2libc"
-      rm -rf \
-        $out/M2-Mesoplanet/M2libc \
-        $out/M2-Planet/M2libc \
-        $out/mescc-tools/M2libc \
-        $out/mescc-tools-extra/M2libc
-    '';
-  };
 
+let
+  expected = import ./bootstrap-sources.nix { };
 in
-runCommand "${name}.nar.xz" {
-  nativeBuildInputs = [ nix xz ];
 
-  passthru = { inherit src; };
+fetchFromGitHub {
+  inherit (expected) name rev;
+  owner = "oriansj";
+  repo = "stage0-posix";
+  sha256 = expected.outputHash;
+  fetchSubmodules = true;
+  postFetch = ''
+    # Seed binaries will be fetched separately
+    echo "Removing seed binaries"
+    rm -rf $out/bootstrap-seeds/*
+
+    # Remove vendored/duplicate M2libc's
+    echo "Removing duplicate M2libc"
+    rm -rf \
+      $out/M2-Mesoplanet/M2libc \
+      $out/M2-Planet/M2libc \
+      $out/mescc-tools/M2libc \
+      $out/mescc-tools-extra/M2libc
+  '';
 
   meta = with lib; {
     description = "Packaged sources for the first bootstrapping stage";
@@ -54,6 +46,4 @@ runCommand "${name}.nar.xz" {
     maintainers = teams.minimal-bootstrap.members;
     platforms = platforms.all;
   };
-} ''
-  nix-store --dump ${src} | xz -c > $out
-''
+}