Major crashing bug fixed, program returned to normal operations

app/ui/main_window.py

@@ -23,6 +23,7 @@ from PyQt6.QtWidgets import (
     QLabel,
     QTabWidget,
     QFileDialog,
+    QDialog,
 )
 
 from app.return_labels import is_emailed_label_order
@@ -59,6 +60,12 @@ class MainWindow(QMainWindow):
         self._send_worker: SendToShipStationWorker | None = None
         self._return_label_worker: CreateReturnLabelWorker | None = None
 
+        # Reused, never-destroyed dialog instances (see the WORKAROUND NOTE
+        # in each dialog's module docstring) - created lazily via
+        # set_order() rather than a fresh instance per ticket.
+        self._pack_ticket_dialog: PackTicketDialog | None = None
+        self._return_label_dialog: ReturnLabelDialog | None = None
+
         self._build_ui()
         self._refresh_everything()
 
@@ -105,10 +112,12 @@ class MainWindow(QMainWindow):
         export_action.triggered.connect(self._on_export_clicked)
         toolbar.addAction(export_action)
 
-        pack_action = QAction("Pack Ticket", self)
-        pack_action.setToolTip("Enter serial numbers and mark packed - select a ticket first")
-        pack_action.triggered.connect(self._on_pack_ticket_clicked)
-        toolbar.addAction(pack_action)
+        self._pack_ticket_action = QAction("Pack Ticket", self)
+        self._pack_ticket_action.setToolTip(
+            "Enter serial numbers and mark packed - select a ticket first"
+        )
+        self._pack_ticket_action.triggered.connect(self._on_pack_ticket_clicked)
+        toolbar.addAction(self._pack_ticket_action)
 
         toolbar.addSeparator()
 
@@ -117,12 +126,12 @@ class MainWindow(QMainWindow):
         emergency_action.triggered.connect(self._on_emergency_send_clicked)
         toolbar.addAction(emergency_action)
 
-        return_label_action = QAction("Create Return Label", self)
-        return_label_action.setToolTip(
+        self._return_label_action = QAction("Create Return Label", self)
+        self._return_label_action.setToolTip(
             "For emailed-return-label tickets (SH007/OK012) - select one in Active Orders first"
         )
-        return_label_action.triggered.connect(self._on_create_return_label_clicked)
-        toolbar.addAction(return_label_action)
+        self._return_label_action.triggered.connect(self._on_create_return_label_clicked)
+        toolbar.addAction(self._return_label_action)
 
         toolbar.addSeparator()
 
@@ -379,10 +388,28 @@ class MainWindow(QMainWindow):
             if proceed != QMessageBox.StandardButton.Yes:
                 return
 
-        dialog = ReturnLabelDialog(order, self)
-        if dialog.exec() != QDialog.DialogCode.Accepted:
+        if self._return_label_dialog is None:
+            self._return_label_dialog = ReturnLabelDialog(order, self)
+            self._return_label_dialog.finished.connect(self._on_return_label_dialog_finished)
+        else:
+            self._return_label_dialog.set_order(order)
+
+        # Non-modal on purpose - see the module docstring in
+        # return_label_dialog.py. Disable the action while it's open so a
+        # second click can't call set_order() on it mid-edit and silently
+        # overwrite whatever the user is in the middle of entering.
+        self._return_label_action.setEnabled(False)
+        self._return_label_dialog.show()
+        self._return_label_dialog.raise_()
+        self._return_label_dialog.activateWindow()
+
+    def _on_return_label_dialog_finished(self, result: int) -> None:
+        self._return_label_action.setEnabled(True)
+        if result != QDialog.DialogCode.Accepted:
             return
 
+        dialog = self._return_label_dialog
+        order = dialog.order
         packages = dialog.get_packages()
         charge_event = dialog.get_charge_event()
         if not packages:
@@ -427,10 +454,28 @@ class MainWindow(QMainWindow):
             )
             return
 
-        dialog = PackTicketDialog(order, self)
-        if dialog.exec() != QDialog.DialogCode.Accepted:
+        if self._pack_ticket_dialog is None:
+            self._pack_ticket_dialog = PackTicketDialog(order, self)
+            self._pack_ticket_dialog.finished.connect(self._on_pack_ticket_dialog_finished)
+        else:
+            self._pack_ticket_dialog.set_order(order)
+
+        # Non-modal on purpose - see the module docstring in
+        # pack_ticket_dialog.py. Disable the action while it's open so a
+        # second click can't call set_order() on it mid-edit and silently
+        # overwrite whatever the user is in the middle of entering/scanning.
+        self._pack_ticket_action.setEnabled(False)
+        self._pack_ticket_dialog.show()
+        self._pack_ticket_dialog.raise_()
+        self._pack_ticket_dialog.activateWindow()
+
+    def _on_pack_ticket_dialog_finished(self, result: int) -> None:
+        self._pack_ticket_action.setEnabled(True)
+        if result != QDialog.DialogCode.Accepted:
             return
 
+        dialog = self._pack_ticket_dialog
+        order = dialog.order
         ticket_number = order.ticket_number or order.external_id
         save_pack_data(ticket_number, dialog.get_serial_numbers(), dialog.get_packed())
         self._refresh_everything()