Merge pull request #3599 from SomberNight/fix_wrapped_c_object_has_been_deleted

fix some crashes when the underlying QT (C/C++) object no longer exists

gui/qt/main_window.py

@@ -2124,7 +2124,12 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         task = partial(self.wallet.sign_message, address, message, password)
 
         def show_signed_message(sig):
-            signature.setText(base64.b64encode(sig).decode('ascii'))
+            try:
+                signature.setText(base64.b64encode(sig).decode('ascii'))
+            except RuntimeError:
+                # (signature) wrapped C/C++ object has been deleted
+                pass
+
         self.wallet.thread.add(task, on_success=show_signed_message)
 
     def do_verify(self, address, message, signature):
@@ -2188,7 +2193,15 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
             return
         cyphertext = encrypted_e.toPlainText()
         task = partial(self.wallet.decrypt_message, pubkey_e.text(), cyphertext, password)
-        self.wallet.thread.add(task, on_success=lambda text: message_e.setText(text.decode('utf-8')))
+
+        def setText(text):
+            try:
+                message_e.setText(text.decode('utf-8'))
+            except RuntimeError:
+                # (message_e) wrapped C/C++ object has been deleted
+                pass
+
+        self.wallet.thread.add(task, on_success=setText)
 
     def do_encrypt(self, message_e, pubkey_e, encrypted_e):
         message = message_e.toPlainText()

gui/qt/util.py

@@ -410,11 +410,15 @@ class MyTreeWidget(QTreeWidget):
 
     def editItem(self, item, column):
         if column in self.editable_columns:
-            self.editing_itemcol = (item, column, item.text(column))
-            # Calling setFlags causes on_changed events for some reason
-            item.setFlags(item.flags() | Qt.ItemIsEditable)
-            QTreeWidget.editItem(self, item, column)
-            item.setFlags(item.flags() & ~Qt.ItemIsEditable)
+            try:
+                self.editing_itemcol = (item, column, item.text(column))
+                # Calling setFlags causes on_changed events for some reason
+                item.setFlags(item.flags() | Qt.ItemIsEditable)
+                QTreeWidget.editItem(self, item, column)
+                item.setFlags(item.flags() & ~Qt.ItemIsEditable)
+            except RuntimeError:
+                # (item) wrapped C/C++ object has been deleted
+                pass
 
     def keyPressEvent(self, event):
         if event.key() in [ Qt.Key_F2, Qt.Key_Return ] and self.editor is None: