trezor: support outdated firmware notifications

Outdated firmware error messages were originally raised from
create_client, which would mean that a client for an outdated device
would not be created.

This had a number of undesirable outcomes due to "client does not exist"
being conflated with "no device is connected".

Instead, we raise in setup_client (which prevents creating new wallets
with outdated devices, BUT shows them in device list), and python-trezor
also raises on most calls (which gives us an error message when opening
wallet and/or trying to do basically anything with it).

This is still suboptimal - i.e., there's currently no way for Electrum to
claim higher version requirement than the underlying python-trezor, and
so minimum_firmware property is pretty much useless ATM.

electrum/plugins/trezor/clientbase.py

@@ -2,12 +2,12 @@ import time
 from struct import pack
 
 from electrum.i18n import _
-from electrum.util import PrintError, UserCancelled
+from electrum.util import PrintError, UserCancelled, UserFacingException
 from electrum.keystore import bip39_normalize_passphrase
 from electrum.bip32 import serialize_xpub, convert_bip32_path_to_list_of_uint32 as parse_path
 
 from trezorlib.client import TrezorClient
-from trezorlib.exceptions import TrezorFailure, Cancelled
+from trezorlib.exceptions import TrezorFailure, Cancelled, OutdatedFirmwareError
 from trezorlib.messages import WordRequestType, FailureType, RecoveryDeviceType
 import trezorlib.btc
 import trezorlib.device
@@ -66,6 +66,8 @@ class TrezorClientBase(PrintError):
                 raise UserCancelled from exc_value
             elif issubclass(exc_type, TrezorFailure):
                 raise RuntimeError(exc_value.message) from exc_value
+            elif issubclass(exc_type, OutdatedFirmwareError):
+                raise UserFacingException(exc_value) from exc_value
             else:
                 return False
         return True
@@ -163,12 +165,10 @@ class TrezorClientBase(PrintError):
         self.print_error("closing client")
         self.clear_session()
 
-    def firmware_version(self):
-        f = self.features
-        return (f.major_version, f.minor_version, f.patch_version)
-
-    def atleast_version(self, major, minor=0, patch=0):
-        return self.firmware_version() >= (major, minor, patch)
+    def is_uptodate(self):
+        if self.client.is_outdated():
+            return False
+        return self.client.version >= self.plugin.minimum_firmware
 
     def get_trezor_model(self):
         """Returns '1' for Trezor One, 'T' for Trezor T."""

electrum/plugins/trezor/trezor.py

@@ -141,20 +141,7 @@ class TrezorPlugin(HW_PluginBase):
 
         self.print_error("connected to device at", device.path)
         # note that this call can still raise!
-        client = TrezorClientBase(transport, handler, self)
-
-        if not client.atleast_version(*self.minimum_firmware):
-            msg = (_('Outdated {} firmware for device labelled {}. Please '
-                     'download the updated firmware from {}')
-                   .format(self.device, client.label(), self.firmware_URL))
-            self.print_error(msg)
-            if handler:
-                handler.show_error(msg)
-            else:
-                raise UserFacingException(msg)
-            return None
-
-        return client
+        return TrezorClientBase(transport, handler, self)
 
     def get_client(self, keystore, force_pair=True):
         devmgr = self.device_manager()
@@ -265,6 +252,13 @@ class TrezorPlugin(HW_PluginBase):
         if client is None:
             raise UserFacingException(_('Failed to create a client for this device.') + '\n' +
                                       _('Make sure it is in the correct state.'))
+
+        if not client.is_uptodate():
+            msg = (_('Outdated {} firmware for device labelled {}. Please '
+                     'download the updated firmware from {}')
+                   .format(self.device, client.label(), self.firmware_URL))
+            raise UserFacingException(msg)
+
         # fixme: we should use: client.handler = wizard
         client.handler = self.create_handler(wizard)
         if not device_info.initialized: