fix(config): reject blank root before NVM4313

config/config.go

@@ -9,7 +9,7 @@ func Prepare(key, value *string) (skip bool, deferredFn func(), err error) {
 	case "root":
 		deferredFn, err = processRoot(value)
 
-		if err != nil && (strings.Contains(err.Error(), "blocked") || strings.Contains(err.Error(), "NVM4313")) {
+		if err != nil && (strings.Contains(err.Error(), "blocked") || strings.Contains(err.Error(), "NVM4313") || strings.Contains(err.Error(), "non-empty path")) {
 			skip = true
 		}
 

config/root.go

@@ -18,6 +18,10 @@ func processRoot(value *string) (deferredFn func(), err error) {
 	}
 
 	*value = strings.Trim(*value, `"`) // Remove potential quotes from input
+	if strings.TrimSpace(*value) == "" {
+		err = fmt.Errorf("root must be a non-empty path")
+		return
+	}
 
 	sourceRoot := filepath.Clean(s.Root)
 	targetRoot := filepath.Clean(settings.Expand(*value))

config/root_test.go

@@ -0,0 +1,34 @@
+package config
+
+import (
+	"os/exec"
+	"strings"
+	"testing"
+
+	prefs "common/preferences"
+	"common/settings"
+)
+
+func TestPrepareRootRejectsBlank(t *testing.T) {
+	prefs.ROOT = "HKCU/Software/NVMTest/config_empty_root"
+	prefs.ROOTS = []string{prefs.ROOT}
+	t.Cleanup(func() {
+		exec.Command("reg", "delete", `HKCU\Software\NVMTest\config_empty_root`, "/f").Run()
+	})
+	settings.Load(true)
+
+	for _, raw := range []string{"", "   ", `""`, `"   "`} {
+		key := "root"
+		value := raw
+		skip, _, err := Prepare(&key, &value)
+		if err == nil || !strings.Contains(err.Error(), "root must be a non-empty path") {
+			t.Fatalf("Prepare(root=%q) = skip=%v err=%v, want non-empty path", raw, skip, err)
+		}
+		if strings.Contains(err.Error(), "NVM4313") {
+			t.Fatalf("Prepare(root=%q) used NVM4313: %v", raw, err)
+		}
+		if !skip {
+			t.Fatalf("Prepare(root=%q) skip=false, want true", raw)
+		}
+	}
+}