compose-fs.patch

diff --git a/nixos/modules/system/etc/build-composefs-dump.py b/nixos/modules/system/etc/build-composefs-dump.py
index fe739a621ec4..42287ea35842 100644
--- a/nixos/modules/system/etc/build-composefs-dump.py
+++ b/nixos/modules/system/etc/build-composefs-dump.py
@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-
 """Build a composefs dump from a Json config
 
 See the man page of composefs-dump for details about the format:
@@ -57,8 +55,9 @@ def __init__(
         path: str | None = None,
     ):
         if path is None:
-            path = attrs["target"]
-        self.path = path
+            self.path = attrs["target"]
+        else:
+            self.path = path
         self.size = size
         self.filetype = filetype
         self.mode = mode
@@ -176,14 +175,25 @@ def main() -> None:
                 add_leading_directories(glob_target, attrs, paths)
         else:  # Without globbing
             if mode == "symlink" or mode == "direct-symlink":
-                composefs_path = ComposefsPath(
-                    attrs,
-                    # A high approximation of the size of a symlink
-                    size=100,
-                    filetype=FileType.symlink,
-                    mode="0777",
-                    payload=source,
-                )
+                if text := attrs.get("text"):
+                    Path(target).write_text(text)
+                    composefs_path = ComposefsPath(
+                        attrs,
+                        # A high approximation of the size of a symlink
+                        size=100,
+                        filetype=FileType.file,
+                        mode="0777",
+                        payload=text,
+                    )
+                else:
+                    composefs_path = ComposefsPath(
+                        attrs,
+                        # A high approximation of the size of a symlink
+                        size=100,
+                        filetype=FileType.symlink,
+                        mode="0777",
+                        payload=source,
+                    )
             elif os.path.isdir(source):
                 composefs_path = ComposefsPath(
                     attrs,
diff --git a/nixos/modules/system/etc/etc.nix b/nixos/modules/system/etc/etc.nix
index 594b9aab61b7..1189d7b357fb 100644
--- a/nixos/modules/system/etc/etc.nix
+++ b/nixos/modules/system/etc/etc.nix
@@ -303,20 +303,25 @@ in
       ]) etcHardlinks}
     '';
 
-    system.build.etcMetadataImage =
-      let
-        etcJson = pkgs.writeText "etc-json" (builtins.toJSON etc');
-        etcDump = pkgs.runCommand "etc-dump" { } ''
-          ${lib.getExe pkgs.buildPackages.python3} ${./build-composefs-dump.py} ${etcJson} > $out
-        '';
-      in
-      pkgs.runCommand "etc-metadata.erofs" {
-        nativeBuildInputs = with pkgs.buildPackages; [ composefs erofs-utils ];
-      } ''
-        mkcomposefs --from-file ${etcDump} $out
-        fsck.erofs $out
-      '';
-
+    system.build.etcMetadataImage = pkgs.runCommand "etc-metadata.erofs" {
+      etcJson = builtins.toJSON (builtins.map (attr: {
+        inherit (attr) target mode uid gid;
+        # avoid create text derivations if we can
+        source = if attr.text == null then attr.source else attr.text;
+        text = attr.text;
+      }) etc');
+      passAsFile = [ "etcJson" ];
+      nativeBuildInputs = with pkgs.buildPackages; [
+        (writers.writePython3Bin "build-composefs-dump" {} (builtins.readFile ./build-composefs-dump.py))
+        composefs
+        erofs-utils
+      ];
+    } ''
+      build-composefs-dump "$etcJsonPath" > etc-dump
+      cat etc-dump
+      mkcomposefs --from-file etc-dump $out
+      fsck.erofs $out
+   '';
   };
 
 }