Add version upgrade plug-in to remove settings

Contributes to issue CURA-7328.

plugins/VersionUpgrade/VersionUpgrade45to46/VersionUpgrade45to46.py

@@ -0,0 +1,74 @@
+# Copyright (c) 2020 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+import configparser
+from typing import Tuple, List
+import io
+from UM.VersionUpgrade import VersionUpgrade
+
+_removed_settings = {
+    "machine_filament_park_distance"
+}
+
+class VersionUpgrade45to46(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
+
+    ##  Upgrades Preferences to have the new version number.
+    #
+    #   This renames the renamed settings in the list of visible settings.
+    def upgradePreferences(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        # Update version number.
+        parser["metadata"]["setting_version"] = "12"
+
+        # Remove deleted settings from the visible settings list.
+        visible_settings = set(parser["general"]["visible_settings"].split(";"))
+        for removed in _removed_settings:
+            if removed in visible_settings:
+                visible_settings.remove(removed)
+        parser["general"]["visible_settings"] = ";".join(visible_settings)
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]
+
+    ##  Upgrades instance containers to have the new version
+    #   number.
+    #
+    #   This renames the renamed settings in the containers.
+    def upgradeInstanceContainer(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None, comment_prefixes = ())
+        parser.read_string(serialized)
+
+        # Update version number.
+        parser["metadata"]["setting_version"] = "12"
+
+        if "values" in parser:
+            for removed in _removed_settings:
+                if removed in parser["values"]:
+                    del parser["values"][removed]
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]
+
+    ##  Upgrades stacks to have the new version number.
+    def upgradeStack(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        # Update version number.
+        if "metadata" not in parser:
+            parser["metadata"] = {}
+        parser["metadata"]["setting_version"] = "12"
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]