fix(filegen): Allow using filegen with mixed architectures

[tlater-famedly]

Since the filegen manifest ends up containing architecture-dependent file hashes, we can't actually use smfh ergonomically.

We considered doing something crazy using symlinkJoin, and even content-addressed derivations, but these solutions didn't pan out.

For now we will just remove the manifest, and assume that we will not have to delete files, instead scripting the copy operations ourselves (with generous help from the install command).

We can add support for manifests and file deletion in the future.

[cursor]

PR Summary

Low Risk
Changes only Nix dev tooling and how generated config files are copied locally; no runtime app, auth, or data paths.

Overview
Replaces the smfh-based filegen workflow so generated dev files can be applied without a committed manifest that embedded architecture-specific store paths.

nix run .#filegen-activate now runs a Nushell script that reads an ephemeral JSON manifest and copies each entry with coreutils install (--compare, mode/clobber via the existing clobber option). The filegen-deactivate app and smfh package option are removed; file operations are limited to copy (symlink/modify/delete/etc. dropped from the schema).

Repo-facing cleanup: .config/filegen-manifest.json is no longer generated into the tree or listed in .gitattributes; clobber-by-default is removed from flake config. The activate manifest JSON is still written at evaluation time for the script only—it is not installed as a tracked file.

^{Reviewed by Cursor Bugbot for commit 3ebd448. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

Bugbot Autofix prepared a fix for the issue found in the latest run.

• ✅ Fixed: Clobber false still overwrites
  • Replaced the ineffective '--backup=numbered' (which still overwrites the destination) with a guard that skips the install when clobber is false and the target already exists.

Or push these changes by commenting:

@cursor push f297c84c7f

Preview (f297c84c7f)

diff --git a/.gitattributes b/.gitattributes
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,4 +1,3 @@
 .pre-commit-config.yaml linguist-generated
 .github/workflows/check-pre-commit-hooks.yml linguist-generated
 .gitattributes linguist-generated
-.config/filegen-manifest.json linguist-generated

diff --git a/nix/general/default.nix b/nix/general/default.nix
--- a/nix/general/default.nix
+++ b/nix/general/default.nix
@@ -16,10 +16,7 @@
   config.perSystem =
     { config, ... }:
     lib.mkMerge [
-      {
-        filegen.settings.clobber-by-default = true;
-        githubActions.enable = true;
-      }
+      { githubActions.enable = true; }
 
       (lib.mkIf (config.githubActions.workflows != { }) {
         filegen.settings.files = lib.mapAttrsToList (workflow: source: {

diff --git a/nix/modules/filegen.nix b/nix/modules/filegen.nix
--- a/nix/modules/filegen.nix
+++ b/nix/modules/filegen.nix
@@ -1,7 +1,6 @@
 { flake-parts-lib, lib, ... }:
 let
   inherit (lib) types;
-  smfh.version = 3;
 in
 {
   options.perSystem = flake-parts-lib.mkPerSystemOption (
@@ -21,10 +20,6 @@
               To generate the files, an "app" named `filegen-activate` is created,
               which can be executed with `nix run .#filegen-activate`.
 
-              The configuration is as expected by
-              [smfh](https://github.com/feel-co/smfh), which is used
-              to perform the actual file manipulations.
-
               ---
 
               Note: This module does *not* attempt to protect against writes to or
@@ -50,13 +45,7 @@
                         Normally, this should be set to `copy`.
                       '';
 
-                      type = types.enum [
-                        "copy"
-                        "symlink"
-                        "modify"
-                        "directory"
-                        "delete"
-                      ];
+                      type = types.enum [ "copy" ];
                     };
 
                     target = lib.mkOption {
@@ -85,20 +74,6 @@
                       type = types.nullOr types.bool;
                     };
 
-                    ignore-modification = lib.mkOption {
-                      description = ''
-                        Whether to skip content integrity checks during activation.
-                      '';
-                      type = types.nullOr types.bool;
-                    };
-
-                    deactivate = lib.mkOption {
-                      description = ''
-                        If enabled, `filegen-deactivate` will ignore this file.
-                      '';
-                      type = types.nullOr types.bool;
-                    };
-
                     permissions = lib.mkOption {
                       description = ''
                         The permissions of the created file.
@@ -115,52 +90,20 @@
                       # default.
                       default = "600";
                     };
-
-                    # Not implemented:
-                    #
-                    # - permissions/uid/gid, as these should not matter for a
-                    #   project repo.
-                    # - follow_symlinks, since for a git repo we should never
-                    #   want to symlink to absolute paths.
                   };
                 }
               )
             );
           };
-
-          clobber-by-default = lib.mkOption {
-            description = ''
-              Whether files should be overwritten by default.
-            '';
-            type = types.nullOr types.bool;
-          };
         };
 
-        smfhPackage = lib.mkOption {
+        scripts.activate = lib.mkOption {
           description = ''
-            The smfh package to use.
+            A script that applies the files configured with `filegen.files`.
           '';
-          default = pkgs.smfh;
-          type = types.package;
+          readOnly = true;
+          type = types.pathInStore;
         };
-
-        scripts = {
-          activate = lib.mkOption {
-            description = ''
-              A script that applies the files configured with `filegen.files`.
-            '';
-            readOnly = true;
-            type = types.pathInStore;
-          };
-
-          deactivate = lib.mkOption {
-            description = ''
-              A script that removes configured by a previous invocation of the activate script.
-            '';
-            readOnly = true;
-            type = types.pathInStore;
-          };
-        };
       };
     }
   );
@@ -169,9 +112,7 @@
     { pkgs, config, ... }:
     let
       cfg = config.filegen;
-      new-manifest = pkgs.writers.writeJSON "filegen-manifest.json" (
-        config.filegen.settings // { inherit (smfh) version; }
-      );
+      new-manifest = pkgs.writers.writeJSON "filegen-manifest.json" config.filegen.settings;
     in
     {
       filegen.settings.files = [
@@ -185,7 +126,7 @@
           target = ".gitattributes";
           source = pkgs.writeTextFile {
             name = ".gitattributes";
-            text = lib.pipe (cfg.settings.files ++ [ { target = ".config/filegen-manifest.json"; } ]) [
+            text = lib.pipe cfg.settings.files [
               (map (file: lib.removePrefix "./" file.target))
               (map (target: "${target} linguist-generated"))
               lib.concatLines
@@ -198,22 +139,24 @@
           activate = pkgs.writers.writeNuBin "filegen-apply-script" ''
             cd (git rev-parse --show-toplevel)
 
-            (${lib.getExe cfg.smfhPackage}
-              --impure
-              diff
-              --fallback
-              ${new-manifest}
-              .config/filegen-manifest.json)
-
-            mkdir .config
-            cp --preserve [] ${new-manifest} .config/filegen-manifest.json
-            chmod 600 .config/filegen-manifest.json
+            for file in (open '${new-manifest}' | $in.files) {
+              match $file.type {
+                "copy" => {
+                  if (($file.clobber | default true) or not ($file.target | path exists)) {
+                    (${lib.getExe' pkgs.coreutils "install"}
+                      -D
+                      --compare
+                      $'--mode=($file.permissions)'
+                      $file.source $file.target)
+                  }
+                },
+                _ => {
+                  print $"Type '($file.type)' for '($file.source)' is currently unsupported"
+                  exit 1
+                }
+              }
+            }
           '';
-
-          deactivate = pkgs.writers.writeNuBin "filegen-deactivate-script" ''
-            cd (git rev-parse --show-toplevel)
-            ${lib.getExe cfg.smfhPackage} deactivate .config/filegen-manifest.json
-          '';
         in
         {
           filegen-activate = {
@@ -223,14 +166,6 @@
               package = activate;
             };
           };
-
-          filegen-deactivate = {
-            program = lib.getExe deactivate;
-            meta = {
-              description = "Uninstall all files previously installed using `filegen-activate`";
-              package = deactivate;
-            };
-          };
         };
     };
 }

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^{Reviewed by Cursor Bugbot for commit 1273e28. Configure here.}