Allow deleting user_creds when can't be decrypted

There are situations when the auth_encryption_key changes
and customer wants to delete old stacks. We should allow
deleting those stacks.

Task: #42055
Change-Id: Ifc8c19e181902566d4f295fa979ab6869a4e0852

1 files changed, 4 insertions, 2 deletions

diff --git a/heat/engine/stack.py b/heat/engine/stack.py
index 829609f06..d9fea31f9 100644
--- a/heat/engine/stack.py
+++ b/heat/engine/stack.py
@@ -1881,11 +1881,13 @@ class Stack(collections.abc.Mapping):
     def _try_get_user_creds(self):
         # There are cases where the user_creds cannot be returned
         # due to credentials truncated when being saved to DB.
-        # Ignore this error instead of blocking stack deletion.
+        # Also, there are cases where auth_encryption_key has
+        # changed for some reason.
+        # Ignore these errors instead of blocking stack deletion.
         try:
             return ucreds_object.UserCreds.get_by_id(self.context,
                                                      self.user_creds_id)
-        except exception.Error:
+        except (exception.Error, exception.InvalidEncryptionKey):
             LOG.exception("Failed to retrieve user_creds")
             return None