fix(bundler): swap WIX registry search order to prioritize InstallDir (#14945)

Author: veeceey

.changes/fix-wix-registry-search-order.md

@@ -0,0 +1,5 @@
+---
+"tauri-bundler": patch:bug
+---
+
+Fix WIX installer registry search order so that the named `InstallDir` key takes priority over the NSIS default key, preventing install location from changing on updates.

crates/tauri-bundler/src/bundle/windows/msi/main.wxs

@@ -70,12 +70,16 @@
         <Property Id="ARPURLUPDATEINFO" Value="{{homepage}}"/>
         {{/if}}
 
+        <!-- NOTE: The order of RegistrySearch elements below matters. In WIX, when multiple
+             RegistrySearch elements are listed under a single Property, the LAST successful
+             match wins. We list the NSIS default-key search first and the MSI InstallDir
+             search second so that the MSI-specific path takes priority when both keys exist. -->
         <Property Id="INSTALLDIR">
-          <!-- First attempt: Search for "InstallDir" -->
-          <RegistrySearch Id="PrevInstallDirWithName" Root="HKCU" Key="Software\\{{manufacturer}}\\{{product_name}}" Name="InstallDir" Type="raw" />
-
-          <!-- Second attempt: If the first fails, search for the default key value (this is how the nsis installer currently stores the path) -->
+          <!-- First attempt: Search for the default key value (this is how the nsis installer stores the path) -->
           <RegistrySearch Id="PrevInstallDirNoName" Root="HKCU" Key="Software\\{{manufacturer}}\\{{product_name}}" Type="raw" />
+
+          <!-- Second attempt: Search for "InstallDir" which takes priority if found (this is how the msi installer stores the path) -->
+          <RegistrySearch Id="PrevInstallDirWithName" Root="HKCU" Key="Software\\{{manufacturer}}\\{{product_name}}" Name="InstallDir" Type="raw" />
         </Property>
 
         <!-- launch app checkbox -->