Merge pull request #291 from hercules-ci/better-dogfooding

Add `flake-parts-lib.importAndPublish`

dev/tests/eval-tests.nix

@@ -169,6 +169,22 @@ rec {
       partitionedAttrs.devShells = "dev";
     });
 
+  dogfoodProvider = mkFlake
+    { inputs.self = { }; }
+    ({ flake-parts-lib, ... }: {
+      imports = [
+        (flake-parts-lib.importAndPublish "dogfood" { flake.marker = "dogfood"; })
+      ];
+    });
+
+  dogfoodConsumer = mkFlake
+    { inputs.self = { }; }
+    ({ flake-parts-lib, ... }: {
+      imports = [
+        dogfoodProvider.modules.flake.dogfood
+      ];
+    });
+
   runTests = ok:
 
     assert empty == {
@@ -255,6 +271,9 @@ rec {
 
     assert builtins.isAttrs partitionWithoutExtraInputsFlake.devShells.x86_64-linux;
 
+    assert dogfoodProvider.marker == "dogfood";
+    assert dogfoodConsumer.marker == "dogfood";
+
     ok;
 
   result = runTests "ok";

lib.nix

@@ -221,6 +221,20 @@ let
     importApply =
       modulePath: staticArgs:
       lib.setDefaultModuleLocation modulePath (import modulePath staticArgs);
+
+    /**
+      `importAndPublish name module` returns a module that both imports the `module`, and exposes it as flake attribute `modules.flake.${name}`.
+
+      This also imports the optional [`modules`](https://flake.parts/options/flake-parts-modules.html) module to support that.
+    */
+    importAndPublish = name: module: { lib, ... }: {
+      _class = "flake";
+      imports = [
+        module
+        ./extras/modules.nix
+      ];
+      flake.modules.flake.${name} = module;
+    };
   };
 
   # A best effort, lenient estimate. Please use a recent nixpkgs lib if you