Check native overlay link targets

facade_main_relative_test.go

@@ -218,3 +218,43 @@ func TestLayeredOverlayNativeContext(t *testing.T) {
 	}
 	t.Fatalf("diagnostics = %#v", err.(*configkit.LoadError).Diagnostics())
 }
+
+func TestLayeredOverlayNativeLinks(t *testing.T) {
+	for _, tc := range []struct {
+		name, mainPath, target string
+		want                   configkit.Code
+	}{
+		{"outside root", "scope/main.yml", "../../outside.yml", configkit.CodeOverlayOutsideRoot},
+		{"overlay aliases main", "scope/main.yml", "../main.yml", configkit.CodeOverlayRepeated},
+		{"main aliases overlay target", "scope/alias.yml", "../target.yml", configkit.CodeOverlayRepeated},
+		{"contained overlay", "scope/main.yml", "../target.yml", ""},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			native := configkit.NewFilesystem("bundle", fstest.MapFS{
+				"scope/main.yml":          {Data: []byte("count: 1\n")},
+				"scope/alias.yml":         {Data: []byte("target.yml"), Mode: os.ModeSymlink},
+				"scope/target.yml":        {Data: []byte("count: 7\n")},
+				"scope/overlays/test.yml": {Data: []byte(tc.target), Mode: os.ModeSymlink},
+				"outside.yml":             {Data: []byte("count: 9\n")},
+			})
+			main := configkit.Input{Source: native.File(tc.mainPath), Filesystem: &configkit.FilesystemContext{Root: "scope", FS: &native}}
+			result, err := configkit.LoadLayered(main, configkit.LayeredOptions[layeredFacadeConfig]{Overlay: "test"})
+			if tc.want != "" {
+				if err == nil {
+					t.Fatal("overlay link unexpectedly loaded")
+				}
+				diagnostics := err.(*configkit.LoadError).Diagnostics()
+				if len(diagnostics) != 1 || diagnostics[0].Code != tc.want {
+					t.Fatalf("diagnostics = %#v, want %v", diagnostics, tc.want)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatal(err)
+			}
+			if result.Config.Count != 7 || result.Sources()[1].Path != "scope/target.yml" {
+				t.Fatalf("config = %#v, sources = %#v", result.Config, result.Sources())
+			}
+		})
+	}
+}