Chain exceptions from LibsecretPersistence (#20380)

Author: chlowell

sdk/identity/azure-identity/azure/identity/_persistent_cache.py

@@ -2,14 +2,19 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 # ------------------------------------
+import logging
 import os
 import sys
 from typing import TYPE_CHECKING
 
+import six
+
 if TYPE_CHECKING:
     from typing import Any
     import msal_extensions
 
+_LOGGER = logging.getLogger(__name__)
+
 
 class TokenCachePersistenceOptions(object):
     """Options for persistent token caching.
@@ -86,12 +91,16 @@ def _get_persistence(allow_unencrypted, account_name, cache_name):
             return msal_extensions.LibsecretPersistence(
                 file_path, cache_name, {"MsalClientID": "Microsoft.Developer.IdentityService"}, label=account_name
             )
-        except ImportError:
+        except Exception as ex:  # pylint:disable=broad-except
+            _LOGGER.debug('msal-extensions is unable to encrypt a persistent cache: "%s"', ex, exc_info=True)
             if not allow_unencrypted:
-                raise ValueError(
-                    "PyGObject is required to encrypt the persistent cache. Please install that library or "
-                    + 'specify "allow_unencrypted_storage=True" to store the cache without encryption.'
+                error = ValueError(
+                    "Cache encryption is impossible because libsecret dependencies are not installed or are unusable,"
+                    + " for example because no display is available (as in an SSH session). The chained exception has"
+                    + ' more information. Specify "allow_unencrypted_storage=True" to store the cache unencrypted'
+                    + " instead of raising this exception."
                 )
-            return msal_extensions.FilePersistence(file_path)
+                six.raise_from(error, ex)
+        return msal_extensions.FilePersistence(file_path)
 
     raise NotImplementedError("A persistent cache is not available in this environment.")