handle unpickling errors

permacache/cache.py

@@ -1,5 +1,7 @@
 import os
 import shutil
+import sys
+from pickle import UnpicklingError
 
 from appdirs import user_cache_dir
 
@@ -44,7 +46,14 @@ def __call__(self, *args, **kwargs):
 
         with self.shelf as db:
             if key in db:
-                return db[key]
+                try:
+                    return db[key]
+                except UnpicklingError as e:
+                    # total hack. not sure why this is happening
+                    print(f"Unpickling error: {e}", file=sys.stderr)
+                    print(repr(key), file=sys.stderr)
+                    print("Deleting key", file=sys.stderr)
+                    del db[key]
         value = self._run_underlying(*args, **kwargs)
         with self.shelf as db:
             # TODO maybe check if key is now in db

setup.py

@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name="permacache",
-    version="3.7.2",
+    version="3.7.3",
     author="Kavi Gupta",
     author_email="[email protected]",
     description="Permanant cache.",