Significantly improve the speed of the version upgrader

This knocked about 10 seconds from my boot time. Huzzah :D

cura/CuraApplication.py

@@ -1218,6 +1218,8 @@ class CuraApplication(QtApplication):
             # Once we're at this point, everything should have been flushed already (past OnExitCallbackManager).
             # It's more difficult to call sys.exit(0): That requires that it happens as the result of a pyqtSignal-emit.
             # (See https://doc.qt.io/qt-6/qcoreapplication.html#quit)
+            # WARNING: With this in place you CAN NOT use cProfile. You will need to replace the next line with pass
+            # for it to work!
             os._exit(0)
 
         return super().event(event)

plugins/VersionUpgrade/VersionUpgrade22to24/VersionUpgrade.py

@@ -152,9 +152,3 @@ class VersionUpgrade22to24(VersionUpgrade):
         config.write(output)
         return [filename], [output.getvalue()]
 
-    def getCfgVersion(self, serialised: str) -> int:
-        parser = configparser.ConfigParser(interpolation = None)
-        parser.read_string(serialised)
-        format_version = int(parser.get("general", "version")) #Explicitly give an exception when this fails. That means that the file format is not recognised.
-        setting_version = int(parser.get("metadata", "setting_version", fallback = "0"))
-        return format_version * 1000000 + setting_version

plugins/VersionUpgrade/VersionUpgrade27to30/VersionUpgrade27to30.py

@@ -33,23 +33,6 @@ _renamed_i18n = {
 
 
 class VersionUpgrade27to30(VersionUpgrade):
-    ##  Gets the version number from a CFG file in Uranium's 2.7 format.
-    #
-    #   Since the format may change, this is implemented for the 2.7 format only
-    #   and needs to be included in the version upgrade system rather than
-    #   globally in Uranium.
-    #
-    #   \param serialised The serialised form of a CFG file.
-    #   \return The version number stored in the CFG file.
-    #   \raises ValueError The format of the version number in the file is
-    #   incorrect.
-    #   \raises KeyError The format of the file is incorrect.
-    def getCfgVersion(self, serialised: str) -> int:
-        parser = configparser.ConfigParser(interpolation = None)
-        parser.read_string(serialised)
-        format_version = int(parser.get("general", "version")) #Explicitly give an exception when this fails. That means that the file format is not recognised.
-        setting_version = int(parser.get("metadata", "setting_version", fallback = "0"))
-        return format_version * 1000000 + setting_version
 
     ##  Upgrades a preferences file from version 2.7 to 3.0.
     #

plugins/VersionUpgrade/VersionUpgrade460to462/VersionUpgrade460to462.py

@@ -33,12 +33,6 @@ default_qualities_per_nozzle_and_material = {
 
 
 class VersionUpgrade460to462(VersionUpgrade):
-    def getCfgVersion(self, serialised: str) -> int:
-        parser = configparser.ConfigParser(interpolation = None)
-        parser.read_string(serialised)
-        format_version = int(parser.get("general", "version"))  # Explicitly give an exception when this fails. That means that the file format is not recognised.
-        setting_version = int(parser.get("metadata", "setting_version", fallback = "0"))
-        return format_version * 1000000 + setting_version
 
     def upgradePreferences(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
         """