Merge 2706080bc8 into 1d2a91e8c5

Workaround for an issue after upgrading from WiX Toolset v3 to v5 where the previous
version of Dangerzone is not uninstalled during the upgrade by checking if the older installation
exists in "C:\Program Files (x86)\Dangerzone".

Also handle a special case for Dangerzone 0.8.0 which allows choosing the install location
during install by checking if the registry key for it exists.

Note that this seems to allow installing Dangerzone 0.8.0 after installing Dangerzone from this branch.
In this case the installer errors until Dangerzone 0.8.0 is uninstalled again

install/windows/build-wxs.py

@@ -152,10 +152,6 @@ def main():
         Id="ARPURLINFOABOUT",
         Value="https://freedom.press",
     )
-    ET.SubElement(
-        package_el, "ui:WixUI", Id="WixUI_InstallDir", InstallDirectory="INSTALLFOLDER"
-    )
-    ET.SubElement(package_el, "UIRef", Id="WixUI_ErrorProgressText")
     ET.SubElement(
         package_el,
         "WixVariable",
@@ -174,6 +170,13 @@ def main():
         DowngradeErrorMessage="A newer version of [ProductName] is already installed. If you are sure you want to downgrade, remove the existing installation via Programs and Features.",
     )
 
+    # Add The UI element
+    ui_el = ET.SubElement(package_el, "UI")
+    ET.SubElement(
+        ui_el, "ui:WixUI", Id="WixUI_InstallDir", InstallDirectory="INSTALLFOLDER"
+    )
+    ET.SubElement(ui_el, "UIRef", Id="WixUI_ErrorProgressText")
+
     # Workaround for an issue after upgrading from WiX Toolset v3 to v5 where the previous
     # version of Dangerzone is not uninstalled during the upgrade by checking if the older installation
     # exists in "C:\Program Files (x86)\Dangerzone".