Trezor/KeepKey: force watching only improvements

Only warn about watching only once given a chance to pair.
Failure to pair makes watching-only and warns.
In error message to user, distinguish between failure to connect
and failure to pair.

gui/qt/main_window.py

@@ -311,6 +311,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         title = 'Electrum %s  -  %s' % (self.wallet.electrum_version,
                                         self.wallet.basename())
         if self.wallet.is_watching_only():
+            self.warn_if_watching_only()
             title += ' [%s]' % (_('watching only'))
         self.setWindowTitle(title)
         self.password_menu.setEnabled(self.wallet.can_change_password())

lib/plugins.py

@@ -234,6 +234,13 @@ class BasePlugin(PrintError):
     def settings_dialog(self):
         pass
 
+
+class DeviceNotFoundError(Exception):
+    pass
+
+class DeviceUnpairableError(Exception):
+    pass
+
 Device = namedtuple("Device", "path interface_number id_ product_key")
 DeviceInfo = namedtuple("DeviceInfo", "device description initialized")
 
@@ -368,25 +375,38 @@ class DeviceMgr(PrintError):
                 return self.create_client(device, wallet.handler, plugin)
 
         if force_pair:
-            first_address, derivation = wallet.first_address()
+            return self.force_pair_wallet(plugin, wallet, devices)
-            assert first_address
-
-            # The wallet has not been previously paired, so let the user
-            # choose an unpaired device and compare its first address.
-            info = self.select_device(wallet, plugin, devices)
-            if info:
-                client = self.client_lookup(info.device.id_)
-                if client and client.is_pairable():
-                    # See comment above for same code
-                    client.handler = wallet.handler
-                    # This will trigger a PIN/passphrase entry request
-                    client_first_address = client.first_address(derivation)
-                    if client_first_address == first_address:
-                        self.pair_wallet(wallet, info.device.id_)
-                        return client
 
         return None
 
+    def force_pair_wallet(self, plugin, wallet, devices):
+        first_address, derivation = wallet.first_address()
+        assert first_address
+
+        # The wallet has not been previously paired, so let the user
+        # choose an unpaired device and compare its first address.
+        info = self.select_device(wallet, plugin, devices)
+        if info:
+            client = self.client_lookup(info.device.id_)
+            if client and client.is_pairable():
+                # See comment above for same code
+                client.handler = wallet.handler
+                # This will trigger a PIN/passphrase entry request
+                client_first_address = client.first_address(derivation)
+                if client_first_address == first_address:
+                    self.pair_wallet(wallet, info.device.id_)
+                    return client
+
+        if info and client:
+            # The user input has wrong PIN or passphrase
+            raise DeviceUnpairableError(
+                _('Unable to pair with your %s.') % plugin.device)
+
+        raise DeviceNotFoundError(
+            _('Could not connect to your %s.  Verify the cable is '
+              'connected and that no other application is using it.')
+            % plugin.device)
+
     def unpaired_device_infos(self, handler, plugin, devices=None):
         '''Returns a list of DeviceInfo objects: one for each connected,
         unpaired device accepted by the plugin.'''

plugins/hw_wallet/hw_wallet.py

@@ -39,26 +39,29 @@ class BIP44_HW_Wallet(BIP44_Wallet):
         # handler.  The handler is per-window and preserved across
         # device reconnects
         self.handler = None
-        self.force_watching_only = True
+        self.force_watching_only = False
 
     def set_session_timeout(self, seconds):
         self.print_error("setting session timeout to %d seconds" % seconds)
         self.session_timeout = seconds
         self.storage.put('session_timeout', seconds)
 
+    def set_force_watching_only(self, value):
+        if value != self.force_watching_only:
+            self.force_watching_only = value
+            self.handler.watching_only_changed()
+
     def unpaired(self):
         '''A device paired with the wallet was diconnected.  This can be
         called in any thread context.'''
         self.print_error("unpaired")
-        self.force_watching_only = True
+        self.set_force_watching_only(True)
-        self.handler.watching_only_changed()
 
     def paired(self):
         '''A device paired with the wallet was (re-)connected.  This can be
         called in any thread context.'''
         self.print_error("paired")
-        self.force_watching_only = False
+        self.set_force_watching_only(False)
-        self.handler.watching_only_changed()
 
     def timeout(self):
         '''Called when the wallet session times out.  Note this is called from

plugins/trezor/plugin.py

@@ -20,9 +20,6 @@ from ..hw_wallet import BIP44_HW_Wallet, HW_PluginBase
 # TREZOR initialization methods
 TIM_NEW, TIM_RECOVER, TIM_MNEMONIC, TIM_PRIVKEY = range(0, 4)
 
-class DeviceDisconnectedError(Exception):
-    pass
-
 class TrezorCompatibleWallet(BIP44_HW_Wallet):
 
     def get_public_key(self, bip32_path):
@@ -137,17 +134,15 @@ class TrezorCompatiblePlugin(HW_PluginBase):
         assert self.main_thread != threading.current_thread()
 
         devmgr = self.device_manager()
-        client = devmgr.client_for_wallet(self, wallet, force_pair)
+        try:
+            client = devmgr.client_for_wallet(self, wallet, force_pair)
+        except:
+            wallet.set_force_watching_only(True)
+            raise
 
         if client:
             self.print_error("set last_operation")
             wallet.last_operation = time.time()
-        elif force_pair:
-            msg = (_('Could not connect to your %s.  Verify the '
-                     'cable is connected and that no other app is '
-                     'using it.\nContinuing in watching-only mode '
-                     'until the device is re-connected.') % self.device)
-            raise DeviceDisconnectedError(msg)
 
         return client