refactor({modules,pkgs}/by-name-overlay): De-duplicate in a `nixLib`

2 files changed, 9 insertions, 52 deletions

diff --git a/modules/by-name-overlay.nix b/modules/by-name-overlay.nix
deleted file mode 100644
index 4349e112..00000000
--- a/modules/by-name-overlay.nix
+++ /dev/null
@@ -1,48 +0,0 @@
-# Adapted from this: https://github.com/NixOS/nixpkgs/blob/1814b56453c91192f6d5a6276079948f9fe96c18/pkgs/top-level/by-name-overlay.nix
-{baseDirectory}: let
-  # Taken straight out of the `nixpkgs/lib/lists.nix` file.
-  # We can't depended on `pkgs` (and thus on `lib`), because the `pkgs` module argument
-  # is only defined in modules we import.
-  flatten = x:
-    if builtins.isList x
-    then builtins.concatMap flatten x
-    else [x];
-  # Same thing as flatten.
-  warn =
-    # Since Nix 2.23, https://github.com/NixOS/nix/pull/10592
-    builtins.warn
-    or (
-      # Do not eta reduce v, so that we have the same strictness as `builtins.warn`.
-      msg: v:
-      # `builtins.warn` requires a string message, so we enforce that in our implementation, so that callers aren't accidentally incompatible with newer Nix versions.
-        assert builtins.isString msg;
-          builtins.trace "evaluation warning: ${msg}" v
-    );
-  # Same thing as flatten.
-  mapAttrsToList = f: attrs:
-    builtins.map (name: f name attrs.${name}) (builtins.attrNames attrs);
-
-  # Module files for a single shard
-  # Type: String -> String -> ListOf Path
-  namesForShard = shard: type:
-    if type != "directory"
-    then warn "Ignored non-directory, whilst importing by-name modules: '${shard}'" []
-    else let
-      mkPath = name: _type: let
-        path = baseDirectory + "/${shard}/${name}/module.nix";
-      in
-        if builtins.pathExists path
-        then path
-        else warn "'${builtins.toString path}' does not exist. Skipped" null;
-    in
-      flatten
-      (builtins.filter (it: it != null)
-        (mapAttrsToList
-          mkPath
-          (builtins.readDir (baseDirectory + "/${shard}"))));
-
-  # A list of all module paths.
-  # These can the be simply injected into `import`
-  moduleFiles = flatten (mapAttrsToList namesForShard (builtins.readDir baseDirectory));
-in
-  moduleFiles
diff --git a/modules/default.nix b/modules/default.nix
index a3bc1735..3364c3db 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -1,10 +1,15 @@
 # NOTE: This file **must** not depend on `pkgs`. This is because `pkgs` is defined in a
 # module imported by it, and thus would require infinite recursion.  <2024-10-18>
 {...}: let
-  files = import ./by-name-overlay.nix {
-    baseDirectory =
-      ./by-name;
-  };
+  nixLib = import ../lib {};
+
+  files =
+    builtins.attrValues
+    (nixLib.mkByName {
+      baseDirectory = ./by-name;
+      fileName = "module.nix";
+      finalizeFunction = name: value: value;
+    });
 in {
   imports = files;
 }