wizard: remove finished call, it's unused

qt: call is_finalized before closing the wizard dialog and add a check if wallet can be
    decrypted with the supplied secret (user pw, hw device)

electrum/gui/qt/wizard/wallet.py

@@ -16,7 +16,7 @@ from electrum.i18n import _
 from electrum.keystore import bip44_derivation, bip39_to_seed, purpose48_derivation, ScriptTypeNotSupported
 from electrum.plugin import run_hook, HardwarePluginLibraryUnavailable
 from electrum.storage import StorageReadWriteError
-from electrum.util import WalletFileException, get_new_wallet_name, UserCancelled, UserFacingException
+from electrum.util import WalletFileException, get_new_wallet_name, UserCancelled, UserFacingException, InvalidPassword
 from electrum.wallet import wallet_types
 from .wizard import QEAbstractWizard, WizardComponent
 from electrum.logging import get_logger, Logger
@@ -181,6 +181,29 @@ class QENewWalletWizard(NewWalletWizard, QEAbstractWizard, MessageBoxMixin):
         if db.requires_upgrade():
             self.waiting_dialog(db.upgrade, _('Upgrading wallet format...'))
 
+    def is_finalized(self, wizard_data: dict) -> bool:
+        # check decryption of existing wallet and keep wizard open if incorrect.
+
+        if not wizard_data['wallet_exists'] or wizard_data['wallet_is_open']:
+            return True
+
+        wallet_file = wizard_data['wallet_name']
+
+        storage = WalletStorage(wallet_file)
+        if not storage.is_encrypted_with_user_pw() and not storage.is_encrypted_with_hw_device():
+            return True
+
+        try:
+            storage.decrypt(wizard_data['password'])
+        except InvalidPassword:
+            if storage.is_encrypted_with_hw_device():
+                self.show_message('This hardware device could not decrypt this wallet. Is it the correct one?')
+            else:
+                self.show_message('Invalid password')
+            return False
+
+        return True
+
     def waiting_dialog(self, task, msg, on_finished=None):
         dialog = QDialog()
         label = WWLabel(msg)

electrum/gui/qt/wizard/wizard.py

@@ -193,8 +193,10 @@ class QEAbstractWizard(QDialog, MessageBoxMixin):
         wd = page.wizard_data.copy()
         if self.is_last(wd):
             self.submit(wd)
-            self.finished(wd)
-            self.accept()
+            if self.is_finalized(wd):
+                self.accept()
+            else:
+                self.prev()  # rollback the submit above
         else:
             next = self.submit(wd)
             self.load_next_component(next.view, next.wizard_data, next.params)
@@ -219,6 +221,10 @@ class QEAbstractWizard(QDialog, MessageBoxMixin):
         wdata = wizard_data.copy()
         return self.is_last_view(self._current.view, wdata)
 
+    def is_finalized(self, wizard_data: dict) -> bool:
+        ''' Final check before closing the wizard. '''
+        return True
+
 
 class WizardComponent(QWidget):
     updated = pyqtSignal(object)

electrum/wizard.py

@@ -79,10 +79,7 @@ class AbstractWizard:
         # make a clone for next view
         wizard_data = copy.deepcopy(wizard_data)
 
-        is_finished = False
         if 'next' not in nav:
-            # finished
-            is_finished = True
             new_view = WizardViewState(None, wizard_data, {})
         else:
             view_next = nav['next']
@@ -118,9 +115,6 @@ class AbstractWizard:
 
         self.log_stack()
 
-        if is_finished:
-            self.finished(wizard_data)
-
         return new_view
 
     def resolve_prev(self):
@@ -154,9 +148,6 @@ class AbstractWizard:
         else:
             raise Exception(f'last handler for view {view} is not callable nor a bool literal')
 
-    def finished(self, wizard_data: dict):
-        self._logger.debug('finished.')
-
     def reset(self):
         self._stack = []
         self._current = WizardViewState(None, {}, {})