more friendly message for v2 import into v1

pylib/anki/importing/anki2.py

@@ -21,6 +21,10 @@ MID = 2
 MOD = 3
 
 
+class V2ImportIntoV1(Exception):
+    pass
+
+
 class Anki2Importer(Importer):
 
     needMapper = False
@@ -58,7 +62,7 @@ class Anki2Importer(Importer):
             if self.src.db.scalar("select 1 from cards where queue != 0 limit 1"):
                 self.source_needs_upgrade = True
         elif self._importing_v2 and self.col.sched_ver() == 1:
-            raise Exception("must upgrade to new scheduler to import this file")
+            raise V2ImportIntoV1()
 
     def _import(self) -> None:
         self._decks = {}

qt/aqt/importing.py

@@ -14,6 +14,7 @@ import anki.importing as importing
 import aqt.deckchooser
 import aqt.forms
 import aqt.modelchooser
+from anki.importing.anki2 import V2ImportIntoV1
 from anki.importing.apkg import AnkiPackageImporter
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
@@ -394,6 +395,11 @@ def importFile(mw: AnkiQt, file: str) -> None:
                 future.result()
             except zipfile.BadZipfile:
                 showWarning(invalidZipMsg())
+            except V2ImportIntoV1:
+                showWarning(
+                    """\
+To import this deck, please click the Update button at the top of the deck list, then try again."""
+                )
             except Exception as e:
                 err = repr(str(e))
                 if "invalidFile" in err: