flake/templates: propagate the template's checks to the main flake's

.github/workflows/check.yml

@@ -20,4 +20,3 @@ jobs:
           name: nix-community
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
       - run: nix flake check --all-systems --builders ""
-      - run: nix flake check --all-systems --builders "" ./templates/_wrapper/simple --no-write-lock-file

flake-modules/templates.nix

@@ -1,8 +1,60 @@
 {
+  self,
+  inputs,
+  ...
+}: {
   flake.templates = {
     default = {
       path = ../templates/simple;
       description = "A simple nix flake template for getting started with nixvim";
     };
   };
+
+  # The following adds the template flake's checks to the main (current) flake's checks.
+  # It ensures that the template's own checks are successful.
+  perSystem = {
+    pkgs,
+    system,
+    lib,
+    ...
+  }: {
+    checks = let
+      # Approximates https://github.com/NixOS/nix/blob/7cd08ae379746749506f2e33c3baeb49b58299b8/src/libexpr/flake/call-flake.nix#L46
+      # s/flake.outputs/args.outputs/
+      callFlake = args @ {
+        inputs,
+        outputs,
+        sourceInfo,
+      }: let
+        outputs = args.outputs (inputs // {self = result;});
+        result =
+          outputs
+          // sourceInfo
+          // {
+            inherit inputs outputs sourceInfo;
+            _type = "flake";
+          };
+      in
+        result;
+
+      templateFlakeOuputs = callFlake {
+        inputs = {
+          inherit (inputs) flake-parts nixpkgs;
+          nixvim = self;
+        };
+        # Import and read the `outputs` field of the template flake.
+        inherit (import ../templates/simple/flake.nix) outputs;
+        sourceInfo = {};
+      };
+
+      templateChecks = templateFlakeOuputs.checks.${system};
+    in
+      lib.concatMapAttrs
+      (
+        checkName: check: {
+          "template-${checkName}" = check;
+        }
+      )
+      templateChecks;
+  };
 }

templates/simple/config/default.nix

@@ -1,4 +1,4 @@
-{self, ...}: {
+{
   # Import all your configuration modules here
   imports = [
     ./bufferline.nix

templates/simple/flake.nix

@@ -8,7 +8,6 @@
   };
 
   outputs = {
-    self,
     nixvim,
     flake-parts,
     ...
@@ -35,7 +34,7 @@
           module = config;
           # You can use `extraSpecialArgs` to pass additional arguments to your module files
           extraSpecialArgs = {
-            inherit self;
+            # inherit (inputs) foo;
           };
         };
       in {