lib: make overrideable & access via flake

Add a non-system specific `<flake>.lib.nixvim` output, which is
equivalent to the existing `<flake>.lib.<system>.helpers` output.

This is now also wrapped with `lib.makeOverridable` to allow overriding
the function args used to construct the nixvim-lib.

Consistently access nixvim-lib via the new flake output, overriding
where necessary.

docs/default.nix

@@ -1,4 +1,5 @@
 {
+  helpers,
   system,
   nixpkgs,
   nuschtosSearch,
@@ -7,7 +8,6 @@ let
   # We overlay a few tweaks into pkgs, for use in the docs
   pkgs = import ./pkgs.nix { inherit system nixpkgs; };
   inherit (pkgs) lib;
-  helpers = import ../lib { inherit lib; };
 
   nixvimPath = toString ./..;
 

flake-modules/lib.nix

@@ -6,23 +6,28 @@
   ...
 }:
 {
-  _module.args.helpers = import ../lib {
+  # Expose lib as a flake-parts module arg
+  _module.args = {
+    helpers = self.lib.nixvim;
+  };
+
+  # Public `lib` flake output
+  flake.lib =
+    {
+      nixvim = lib.makeOverridable (import ../lib) {
         inherit lib;
         flake = self;
       };
-
+    }
-  # TODO: output lib without pkgs at the top-level
+    // lib.genAttrs config.systems (
-  flake.lib = lib.genAttrs config.systems (
       lib.flip withSystem (
         { pkgs, ... }:
         {
           # NOTE: this is the publicly documented flake output we've had for a while
-        check = import ../lib/tests.nix { inherit self lib pkgs; };
+          check = pkgs.callPackage ../lib/tests.nix { inherit self; };
-        # TODO: no longer needs to be per-system
+
-        helpers = import ../lib {
+          # NOTE: no longer needs to be per-system
-          inherit lib;
+          helpers = self.lib.nixvim;
-          flake = self;
-        };
         }
       )
     );

flake-modules/packages.nix

@@ -1,4 +1,8 @@
-{ inputs, ... }:
+{
+  inputs,
+  helpers,
+  ...
+}:
 {
   perSystem =
     {
@@ -9,6 +13,7 @@
     }:
     {
       packages = import ../docs {
+        inherit helpers;
         inherit system;
         inherit (inputs) nixpkgs;
         inherit (inputs') nuschtosSearch;

lib/tests.nix

@@ -46,9 +46,7 @@ let
     }@args:
     let
       # NOTE: we are importing this just for evalNixvim
-      helpers = import ../lib {
+      helpers = self.lib.nixvim.override {
-        inherit lib;
-        flake = self;
         # TODO: deprecate helpers.enableExceptInTests,
         # add a context option e.g. `config.isTest`?
         _nixvimTests = true;

wrappers/_shared.nix

@@ -59,13 +59,7 @@ in
   config = mkMerge [
     {
       # Make our lib available to the host modules
-      # NOTE: user-facing so we must include the legacy `pkgs` argument
+      lib.nixvim = lib.mkDefault self.lib.nixvim;
-      lib.nixvim = lib.mkDefault (
-        import ../lib {
-          inherit lib;
-          flake = self;
-        }
-      );
 
       # Make nixvim's "extended" lib available to the host's module args
       _module.args.nixvimLib = lib.mkDefault config.lib.nixvim.extendedLib;

wrappers/standalone.nix

@@ -9,11 +9,7 @@ default_pkgs: self:
 }:
 let
   # NOTE: we are importing this just for evalNixvim
-  helpers = import ../lib {
+  helpers = self.lib.nixvim.override { inherit _nixvimTests; };
-    inherit lib _nixvimTests;
-    flake = self;
-  };
-
   inherit (helpers.modules) evalNixvim;
 
   mkNvim =