Explicitly close the importer file descriptor

https://github.com/ankitects/anki/pull 613

pylib/anki/importing/noteimp.py

@@ -107,6 +107,10 @@ class NoteImporter(Importer):
         "Open file and ensure it's in the right format."
         return
 
+    def close(self) -> None:
+        "Closes the open file."
+        return
+
     def importNotes(self, notes: List[ForeignNote]) -> None:
         "Convert each card into a note, apply attributes and add to col."
         assert self.mappingOk()

qt/aqt/importing.py

@@ -361,6 +361,7 @@ def importFile(mw, file):
         mw.progress.start(immediate=True)
         try:
             importer.open()
+            diag = ImportDialog(mw, importer)
         except UnicodeDecodeError:
             mw.progress.finish()
             showUnicodeWarning()
@@ -377,7 +378,7 @@ def importFile(mw, file):
             return
         finally:
             mw.progress.finish()
-        diag = ImportDialog(mw, importer)
+            importer.close()
     else:
         # if it's an apkg/zip, first test it's a valid file
         if importer.__class__.__name__ == "AnkiPackageImporter":