hw: allow bypassing "too old firmware" error when using hw wallets

The framework here is generic enough that it can be used for any hw plugin,
however atm only Trezor is implemented.

closes #5391

electrum/plugins/trezor/clientbase.py

@@ -7,6 +7,7 @@ from electrum.util import UserCancelled, UserFacingException
 from electrum.keystore import bip39_normalize_passphrase
 from electrum.bip32 import BIP32Node, convert_bip32_path_to_list_of_uint32 as parse_path
 from electrum.logging import Logger
+from electrum.plugins.hw_wallet.plugin import OutdatedHwFirmwareException
 
 from trezorlib.client import TrezorClient
 from trezorlib.exceptions import TrezorFailure, Cancelled, OutdatedFirmwareError
@@ -29,6 +30,8 @@ MESSAGES = {
 
 class TrezorClientBase(Logger):
     def __init__(self, transport, handler, plugin):
+        if plugin.is_outdated_fw_ignored():
+            TrezorClient.is_outdated = lambda *args, **kwargs: False
         self.client = TrezorClient(transport, ui=self)
         self.plugin = plugin
         self.device = plugin.device
@@ -62,15 +65,15 @@ class TrezorClientBase(Logger):
     def __enter__(self):
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(self, exc_type, e, traceback):
         self.end_flow()
-        if exc_value is not None:
-            if issubclass(exc_type, Cancelled):
-                raise UserCancelled from exc_value
-            elif issubclass(exc_type, TrezorFailure):
-                raise RuntimeError(str(exc_value)) from exc_value
-            elif issubclass(exc_type, OutdatedFirmwareError):
-                raise UserFacingException(exc_value) from exc_value
+        if e is not None:
+            if isinstance(e, Cancelled):
+                raise UserCancelled from e
+            elif isinstance(e, TrezorFailure):
+                raise RuntimeError(str(e)) from e
+            elif isinstance(e, OutdatedFirmwareError):
+                raise OutdatedHwFirmwareException(e) from e
             else:
                 return False
         return True

electrum/plugins/trezor/trezor.py

@@ -15,7 +15,7 @@ from electrum.logging import get_logger
 
 from ..hw_wallet import HW_PluginBase
 from ..hw_wallet.plugin import (is_any_tx_output_on_change_branch, trezor_validate_op_return_output_and_get_data,
-                                LibraryFoundButUnusable)
+                                LibraryFoundButUnusable, OutdatedHwFirmwareException)
 
 _logger = get_logger(__name__)
 
@@ -275,7 +275,7 @@ class TrezorPlugin(HW_PluginBase):
             msg = (_('Outdated {} firmware for device labelled {}. Please '
                      'download the updated firmware from {}')
                    .format(self.device, client.label(), self.firmware_URL))
-            raise UserFacingException(msg)
+            raise OutdatedHwFirmwareException(msg)
 
         # fixme: we should use: client.handler = wizard
         client.handler = self.create_handler(wizard)