Use exceptions instead of False and None to indicate failure (refs: #17136)

Also fixes a bug which caused the "Settings loaded" infobar to not be
shown if only region settings were loaded (the LocalizationSettingUI.load()
implementation did not return True if a setting was loaded).

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/__init__.py

+class SettingNotFoundError(Exception):
+    pass

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/admin.py

@@ -5,6 +5,7 @@ import shlex
 import subprocess
 
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.utils import read_settings, write_settings
 
 
@@ -41,14 +42,13 @@ class AdminSetting(object):
             if os.path.exists(self.settings_file):
                 raise
 
-    def load(self) -> {True, None}:
+    def load(self):
+        # We don't return the stored value, because the UI can't do
+        # anything with it since it's hashed.
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent admin settings file found (path: %s)", self.settings_file)
-            return None
+            raise SettingNotFoundError("No persistent admin settings file found (path: %s)", self.settings_file)
 
-        # We don't actually return the stored value, because the UI can't do
-        # anything with it since it's hashed. Instead, we just return whether
-        # a value is stored or not.
-        return bool(settings.get('TAILS_USER_PASSWORD'))
+        if settings.get('TAILS_USER_PASSWORD') is None:
+            raise SettingNotFoundError("No admin password setting found in settings file (path: %s)", self.settings_file)

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/formats.py

@@ -2,6 +2,7 @@ import gi
 import logging
 
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.localization import LocalizationSetting, language_from_locale, country_from_locale
 from tailsgreeter.settings.utils import read_settings, write_settings
 
@@ -23,17 +24,15 @@ class FormatsSetting(LocalizationSetting):
             'IS_DEFAULT': is_default,
         })
 
-    def load(self) -> ({str, None}, bool):
+    def load(self) -> (str, bool):
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent formats settings file found (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No persistent formats settings file found (path: %s)", self.settings_file)
 
         formats = settings.get('TAILS_FORMATS')
         if formats is None:
-            logging.debug("No formats setting found in settings file (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No formats setting found in settings file (path: %s)", self.settings_file)
 
         is_default = settings.get('IS_DEFAULT') == 'true'
         logging.debug("Loaded formats setting '%s' (is default: %s)", formats, is_default)

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/keyboard.py

@@ -2,6 +2,7 @@ import gi
 import logging
 
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.localization import LocalizationSetting, ln_iso639_tri, \
     ln_iso639_2_T_to_B, language_from_locale, country_from_locale
 from tailsgreeter.settings.utils import read_settings, write_settings
@@ -36,17 +37,15 @@ class KeyboardSetting(LocalizationSetting):
             'IS_DEFAULT': is_default,
         })
 
-    def load(self) -> ({str, None}, bool):
+    def load(self) -> (str, bool):
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent keyboard settings file found (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No persistent keyboard settings file found (path: %s)", self.settings_file)
 
         keyboard_layout = settings.get('TAILS_XKBLAYOUT')
         if keyboard_layout is None:
-            logging.debug("No keyboard setting found in settings file (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No keyboard setting found in settings file (path: %s)", self.settings_file)
 
         keyboard_variant = settings.get('TAILS_XKBVARIANT')
         if keyboard_variant:

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/language.py

@@ -23,6 +23,7 @@ import logging
 import locale
 
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.localization import LocalizationSetting, \
     language_from_locale, country_from_locale
 from tailsgreeter.settings.utils import read_settings, write_settings
@@ -52,17 +53,15 @@ class LanguageSetting(LocalizationSetting):
             'IS_DEFAULT': is_default,
         })
 
-    def load(self) -> ({str, None}, bool):
+    def load(self) -> (str, bool):
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent language settings file found (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No persistent language settings file found (path: %s)", self.settings_file)
 
         language = settings.get('TAILS_LOCALE_NAME')
         if language is None:
-            logging.debug("No language setting found in settings file (path: %s)", self.settings_file)
-            return None, False
+            raise SettingNotFoundError("No language setting found in settings file (path: %s)", self.settings_file)
 
         is_default = settings.get('IS_DEFAULT') == 'true'
         logging.debug("Loaded language setting '%s' (is default: %s)", language, is_default)

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/localization.py

@@ -47,7 +47,7 @@ class LocalizationSetting(GObject.Object, object):
     def save(self, value: str, is_default: bool):
         pass
 
-    def load(self) -> ({str, None}, bool):
+    def load(self) -> (str, bool):
         pass
 
 

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/macspoof.py

 import logging
 
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.utils import read_settings, write_settings
 
 
@@ -16,17 +17,16 @@ class MacSpoofSetting(object):
         })
         logging.debug('macspoof setting written to %s', self.settings_file)
 
-    def load(self) -> {bool, None}:
+    def load(self) -> bool:
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent macspoof settings file found (path: %s)", self.settings_file)
-            return None
+            raise SettingNotFoundError("No persistent macspoof settings file found (path: %s)", self.settings_file)
 
         value_str = settings.get('TAILS_MACSPOOF_ENABLED')
         if value_str is None:
-            logging.debug("No macspoof setting found in settings file (path: %s)", self.settings_file)
-            return None
+            raise SettingNotFoundError("No macspoof setting found in settings file (path: %s)", self.settings_file)
+
         value = value_str == "true"
         logging.debug("Loaded macspoof setting '%s'", value)
         return value

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/settings/network.py

@@ -2,6 +2,7 @@ import logging
 
 import tailsgreeter.config
 from tailsgreeter.settings.utils import read_settings, write_settings
+from tailsgreeter.settings import SettingNotFoundError
 
 NETCONF_DIRECT = "direct"
 NETCONF_OBSTACLE = "obstacle"
@@ -20,17 +21,15 @@ class NetworkSetting(object):
         })
         logging.debug('network setting written to %s', self.settings_file)
 
-    def load(self) -> {bool, None}:
+    def load(self) -> str:
         try:
             settings = read_settings(self.settings_file)
         except FileNotFoundError:
-            logging.debug("No persistent network settings file found (path: %s)", self.settings_file)
-            return None
+            raise SettingNotFoundError("No persistent network settings file found (path: %s)" % self.settings_file)
 
         value = settings.get('TAILS_NETCONF')
         if value is None:
-            logging.debug("No network setting found in settings file (path: %s)", self.settings_file)
-            return None
+            raise SettingNotFoundError("No network setting found in settings file (path: %s)", self.settings_file)
 
         logging.debug("Loaded network setting '%s'", value)
         return value

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/ui/additional_settings.py

@@ -3,6 +3,7 @@ import gi
 from tailsgreeter import TRANSLATION_DOMAIN
 import tailsgreeter.config
 import tailsgreeter.utils
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.settings.network import NETCONF_DIRECT, NETCONF_DISABLED, NETCONF_OBSTACLE
 from tailsgreeter.ui import _
 from tailsgreeter.ui.setting import GreeterSetting
@@ -43,7 +44,7 @@ class AdditionalSetting(GreeterSetting):
     def on_opened_in_dialog(self):
         pass
 
-    def load(self) -> bool:
+    def load(self):
         pass
 
 
@@ -129,12 +130,12 @@ class AdminSettingUI(AdditionalSetting):
             self._admin_setting.delete()
         super().apply()
 
-    def load(self) -> bool:
-        loaded = self._admin_setting.load()
-        if loaded:
-            self.password = True
-            return True
-        return False
+    def load(self):
+        try:
+            self._admin_setting.load()
+        except SettingNotFoundError:
+            raise
+        self.password = True
 
     def cb_entry_admin_changed(self, editable, user_data=None):
         self.update_check_icon()
@@ -200,14 +201,11 @@ class MACSpoofSettingUI(AdditionalSetting):
         self._macspoof_setting.save(self.spoofing_enabled)
         super().apply()
 
-    def load(self) -> bool:
-        value = self._macspoof_setting.load()
-        if value is None:
-            return False
-        if value == self.spoofing_enabled:
-            return False
-        self.spoofing_enabled = value
-        return True
+    def load(self):
+        try:
+            self.spoofing_enabled = self._macspoof_setting.load()
+        except SettingNotFoundError:
+            raise
 
     def cb_listbox_macspoof_row_activated(self, listbox, row, user_data=None):
         self.spoofing_enabled = row == self.listboxrow_macspoof_on
@@ -268,14 +266,11 @@ class NetworkSettingUI(AdditionalSetting):
         self.main_window.set_bridge_infobar_visibility(is_bridge)
         super().apply()
 
-    def load(self) -> bool:
-        value = self._network_setting.load()
-        if value is None:
-            return False
-        if value == self.value:
-            return False
-        self.value = value
-        return True
+    def load(self):
+        try:
+            self.value = self._network_setting.load()
+        except SettingNotFoundError:
+            raise
 
     def cb_listbox_network_button_press(self, widget, event, user_data=None):
         # On double-click: Close the window and apply chosen setting

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/ui/main_window.py

@@ -24,6 +24,7 @@ import os
 import tailsgreeter                                             # NOQA: E402
 import tailsgreeter.config                                      # NOQA: E402
 import tailsgreeter.utils                                       # NOQA: E402
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.translatable_window import TranslatableWindow
 from tailsgreeter.ui.popover import Popover
 from tailsgreeter.ui import _
@@ -184,12 +185,19 @@ class GreeterMainWindow(Gtk.Window, TranslatableWindow):
         # settings in reversed order.
         settings_loaded = False
         for setting in reversed(list(self.settings.region_settings)):
-            if setting.load():
+            try:
+                setting.load()
                 settings_loaded = True
+            except SettingNotFoundError as e:
+                logging.debug(e)
         for setting in self.settings.additional_settings:
-            if setting.load():
+            try:
+                setting.load()
                 self.add_setting(setting.id)
                 settings_loaded = True
+            except SettingNotFoundError as e:
+                logging.debug(e)
+
         if settings_loaded:
             self.infobar_settings_loaded.set_visible(True)
 

config/chroot_local-includes/usr/lib/python3/dist-packages/tailsgreeter/ui/region_settings.py

@@ -3,6 +3,7 @@ import gi
 
 from tailsgreeter import TRANSLATION_DOMAIN
 import tailsgreeter.config
+from tailsgreeter.settings import SettingNotFoundError
 from tailsgreeter.ui import _
 from tailsgreeter.ui.setting import GreeterSetting
 from tailsgreeter.ui.popover import Popover
@@ -61,9 +62,10 @@ class LocalizationSettingUI(GreeterSetting):
         super().apply()
 
     def load(self):
-        value, is_default = self._setting.load()
-        if value is None:
-            return
+        try:
+            value, is_default = self._setting.load()
+        except SettingNotFoundError:
+            raise
         self.value = value
         self.value_changed_by_user = not is_default
         self.apply()
@@ -178,7 +180,10 @@ class LanguageSettingUI(LocalizationSettingUI):
         self.changed_cb(self.value)
 
     def load(self):
-        super().load()
+        try:
+            super().load()
+        except SettingNotFoundError:
+            raise
         self._setting.apply_language(self.value)
         self.changed_cb(self.value)