Issue #24585: Enables build-to-build upgrades that preserve settings.

Rather than using Burn "Persisted" variables we now add registry keys for each added feature. These can be detected by the installer regardless of which version installed them, and we use this for Modify and Upgrade. In particular, Upgrades can't access the Persisted variables, but can find well-known registry keys.
There are also some changes to the bootstrap app to properly handle upgrades.
Finally, a few minor improvements to the Windows build to keep things tidier.

1 files changed, 12 insertions, 2 deletions

diff --git a/Tools/msi/bundle/Default.wxl b/Tools/msi/bundle/Default.wxl
index 3ecb2fa..19ba7eb 100644
--- a/Tools/msi/bundle/Default.wxl
+++ b/Tools/msi/bundle/Default.wxl
@@ -21,6 +21,8 @@ Continue?</String>
   <String Id="InstallHeader">Install [WixBundleName]</String>
   <String Id="InstallMessage">Select Install Now to install Python with default settings, or choose Customize to enable or disable features.</String>
   <String Id="InstallVersion">Version [WixBundleVersion]</String>
+  <String Id="InstallUpgradeHeader">Upgrade to [WixBundleName]</String>
+  <String Id="InstallUpgradeMessage">Select Upgrade Now to keep your current settings, or choose Customize to enable or disable features.</String>
   <String Id="ConfirmCancelMessage">Are you sure you want to cancel?</String>
   <String Id="ExecuteUpgradeRelatedBundleMessage">Previous version</String>
   <String Id="HelpHeader">Setup Help</String>
@@ -40,8 +42,8 @@ Continue?</String>
     Logs to a specific file. By default, log files are created in %TEMP%.</String>
   <String Id="InstallLicenseLinkText">[WixBundleName] &lt;a href="#"&gt;license terms&lt;/a&gt;.</String>
   <String Id="InstallAcceptCheckbox">I &amp;agree to the license terms and conditions</String>
-  <String Id="InstallJustForMeButton">&amp;Install Now</String>
-  <String Id="InstallJustForMeButtonNote">[DefaultJustForMeTargetDir]
+  <String Id="InstallButton">&amp;Install Now</String>
+  <String Id="InstallButtonNote">[DefaultJustForMeTargetDir]
 
 Includes IDLE, pip and documentation
 Creates shortcuts and file associations</String>
@@ -49,6 +51,13 @@ Creates shortcuts and file associations</String>
   <String Id="InstallCustomButtonNote">Choose location and features</String>
   <String Id="InstallSimpleButton">&amp;Install</String>
   <String Id="InstallSimpleButtonNote">Uses setting preselected by your administrator</String>
+  <String Id="InstallUpgradeButton">&amp;Upgrade Now</String>
+  <String Id="InstallUpgradeButtonNote">[TargetDir]
+
+Replaces your existing installation without changing settings.
+Select Customize to review current options.</String>
+  <String Id="InstallUpgradeCustomButton">C&amp;ustomize installation</String>
+  <String Id="InstallUpgradeCustomButtonNote">Choose location and features</String>
   <String Id="Custom1Header">Optional Features</String>
   <String Id="Custom2Header">Advanced Options</String>
   <String Id="CustomLocationLabel">Customize install location</String>
@@ -107,4 +116,5 @@ Feel free to email &lt;a href="mailto:python-list@python.org"&gt;python-list@pyt
   <String Id="FailureHyperlinkLogText">One or more issues caused the setup to fail. Please fix the issues and then retry setup. For more information see the &lt;a href="#"&gt;log file&lt;/a&gt;.</String>
   <String Id="FailureRestartText">You must restart your computer to complete the rollback of the software.</String>
   <String Id="FailureRestartButton">&amp;Restart</String>
+  <String Id="FailureExistingInstall">Unable to install [WixBundleName] due to an existing install. Use Programs and Features to modify, repair or remove [WixBundleName].</String>
 </WixLocalization>