From 8d2f7e9907af342617f9da69aa398202139d3ddd Mon Sep 17 00:00:00 2001
From: Mika Kuns <mika.kuns@fb-tuning.de>
Date: Wed, 15 Apr 2026 10:27:30 +0200
Subject: [PATCH] fix(installer): null-defensive WelcomePage heading + guard
 unreachable modes

---
 .../Pages/WelcomePage/WelcomePageViewModel.cs            | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageViewModel.cs b/src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageViewModel.cs
index 456be22..0f2c791 100644
--- a/src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageViewModel.cs
+++ b/src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageViewModel.cs
@@ -45,10 +45,15 @@ public partial class WelcomePageViewModel : ObservableObject, IInstallerPage
                 break;
 
             case InstallerMode.Update:
-                Heading = $"Update ClaudeDo  {_context.InstalledVersion}  ->  {_context.LatestVersion}";
+                Heading = $"Update ClaudeDo  {_context.InstalledVersion ?? "?"}  ->  {_context.LatestVersion ?? "?"}";
                 Subheading = "Your tasks, config, and database will be preserved. Click Next to continue.";
-                InstallDirEditable = false;
+                InstallDirEditable = false; // stay where we were installed
                 break;
+
+            default:
+                // Config and any future modes should never reach the wizard; guard loudly if they do.
+                throw new InvalidOperationException(
+                    $"WelcomePage is not valid for installer mode {_context.Mode}");
         }
 
         return Task.CompletedTask;