Handle error case after preflight failure.

client/securedrop_client/gui/conversation/export/export_wizard.py

@@ -206,12 +206,13 @@ def end_wizard_with_error(self, error: ExportStatus) -> None:
         end the wizard.
         """
         if isinstance(self.currentPage(), PreflightPage):
-            self.next()
+            # Update its status so it shows error next self.currentPage()
+            # self.next()
+            logger.debug("On preflight page")
         else:
             while self.currentId() > Pages.ERROR:
                 self.back()
         page = self.currentPage()
-        page.set_complete(False)
         page.update_content(error)
 
     def _create_preflight(self) -> QWizardPage:

client/securedrop_client/gui/conversation/export/export_wizard_page.py

@@ -172,6 +172,7 @@ def stop_animate_header(self) -> None:
 
     @pyqtSlot(object)
     def on_status_received(self, status: ExportStatus) -> None:
+        logger.debug(f"Child page received status {status.value}")
         self.status = status
         self.completeChanged.emit()
         # Some children (not the Prefight Page) may wish to call update_content here
@@ -237,6 +238,7 @@ def nextId(self):
         else:
             return Pages.INSERT_USB
 
+    @pyqtSlot(object)
     def on_status_received(self, status: ExportStatus):
         self.stop_animate_header()
         if status in (ExportStatus.DEVICE_LOCKED, ExportStatus.DEVICE_WRITABLE):
@@ -259,6 +261,9 @@ def on_status_received(self, status: ExportStatus):
         self.body.setText(body)
         self.status = status
 
+    def isComplete(self) -> bool:
+        return False
+
 
 class InsertUSBPage(ExportWizardPage):
     def __init__(self, export, summary):