Ignore existing installation for upgrade if boot modes don't match

This patch checks that the current installation is not proposed as
upgradeable if its boot mode differs from the installer one. This uses
the helper function is_rootfs_uefi().

Signed-off-by: Thierry Escande <thierry.escande@vates.tech>

Author: tescande

product.py

@@ -75,6 +75,15 @@ def isUpgradeable(self):
         self.mount_state()
         result = True
         try:
+            # Don't propose to upgrade a BIOS installation with a UEFI installer and conversely
+            existing_is_uefi = is_rootfs_uefi(self.join_state_path())
+            if existing_is_uefi != constants.UEFI_INSTALLER:
+                    logger.log("Cannot upgrade %s, installer mode (%s) does not match existing boot mode (%s)" %
+                                (self.primary_disk,
+                                "uefi" if constants.UEFI_INSTALLER else "legacy",
+                                "uefi" if existing_is_uefi else "legacy"))
+                    return False
+
             # CA-38459: handle missing firstboot directory e.g. Rio
             if os.path.exists(self.join_state_path('etc/firstboot.d/state')):
                 firstboot_files = [ f for f in os.listdir(self.join_state_path('etc/firstboot.d')) \