fix(client): return empty bundles on 404 instead of crashing (#16)

get_bundles() subscripted the None that fetch_resource returns on any
non-200 response, so an item deleted since the cache was built (404)
raised "'NoneType' object is not subscriptable" during a bitstream
export - a scary CRITICAL line for what is really just "this item is gone".

Record the failing response as _last_err in fetch_resource so callers can
tell a gone resource (404) from a transient 5xx, then in get_bundles treat
a 404 as a clean empty result. Any other failure still falls through and
surfaces to the caller, so it keeps its retry and failure counting.

Co-authored-by: jm <jm@maz>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

dspace_rest_client/client.py

@@ -475,6 +475,9 @@ def fetch_resource(self, url, params=None):
         """
         r = self.api_get(url, params, None)
         if r.status_code != 200:
+            # record the failing response so callers can tell a 404 (the
+            # resource is gone) from a transient 5xx before we drop the body
+            self._last_err = r
             _logger.error(f'Error encountered fetching resource: {r.text}')
             return None
         # ValueError / JSON handling moved to static method
@@ -698,6 +701,12 @@ def get_bundles(self, parent=None, uuid=None, page=0, size=20, sort=None):
         if sort is not None:
             params['sort'] = sort
         r_json = self.fetch_resource(url, params=params)
+        if r_json is None and getattr(self._last_err, 'status_code', None) == 404:
+            # the item (or bundle) no longer exists - a deleted item simply has
+            # no bundles, which is a clean empty result, not a crash. any other
+            # failure falls through and still surfaces to the caller.
+            _logger.info(f'No bundles: resource not found (404) [{url}]')
+            return bundles
         try:
             if single_result:
                 bundles.append(Bundle(r_json))