cache: Use getattr to access _cache.

`_cache` is not an attribute defined on `BaseCache`, but an
implementation detail of django_bmemcache.

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

zerver/lib/import_realm.py

@@ -6,6 +6,7 @@ import shutil
 from mimetypes import guess_type
 from typing import Any, Dict, Iterable, List, Optional, Tuple
 
+import bmemcached
 import orjson
 from bs4 import BeautifulSoup
 from django.conf import settings
@@ -876,7 +877,9 @@ def import_uploads(
                 process_avatars(record)
         else:
             connection.close()
-            cache._cache.disconnect_all()
+            _cache = getattr(cache, "_cache")
+            assert isinstance(_cache, bmemcached.Client)
+            _cache.disconnect_all()
             with multiprocessing.Pool(processes) as p:
                 for out in p.imap_unordered(process_avatars, records):
                     pass

zerver/lib/transfer.py

@@ -3,6 +3,7 @@ import multiprocessing
 import os
 from mimetypes import guess_type
 
+import bmemcached
 from django.conf import settings
 from django.core.cache import cache
 from django.db import connection
@@ -40,7 +41,9 @@ def transfer_avatars_to_s3(processes: int) -> None:
             _transfer_avatar_to_s3(user)
     else:  # nocoverage
         connection.close()
-        cache._cache.disconnect_all()
+        _cache = getattr(cache, "_cache")
+        assert isinstance(_cache, bmemcached.Client)
+        _cache.disconnect_all()
         with multiprocessing.Pool(processes) as p:
             for out in p.imap_unordered(_transfer_avatar_to_s3, users):
                 pass
@@ -71,7 +74,9 @@ def transfer_message_files_to_s3(processes: int) -> None:
             _transfer_message_files_to_s3(attachment)
     else:  # nocoverage
         connection.close()
-        cache._cache.disconnect_all()
+        _cache = getattr(cache, "_cache")
+        assert isinstance(_cache, bmemcached.Client)
+        _cache.disconnect_all()
         with multiprocessing.Pool(processes) as p:
             for out in p.imap_unordered(_transfer_message_files_to_s3, attachments):
                 pass
@@ -101,7 +106,9 @@ def transfer_emoji_to_s3(processes: int) -> None:
             _transfer_emoji_to_s3(realm_emoji)
     else:  # nocoverage
         connection.close()
-        cache._cache.disconnect_all()
+        _cache = getattr(cache, "_cache")
+        assert isinstance(_cache, bmemcached.Client)
+        _cache.disconnect_all()
         with multiprocessing.Pool(processes) as p:
             for out in p.imap_unordered(_transfer_emoji_to_s3, realm_emojis):
                 pass

zilencer/management/commands/mark_all_messages_unread.py

@@ -1,5 +1,6 @@
 from typing import Any
 
+import bmemcached
 from django.conf import settings
 from django.core.cache import cache
 from django.core.management.base import BaseCommand
@@ -14,4 +15,6 @@ class Command(BaseCommand):
     def handle(self, *args: Any, **options: Any) -> None:
         assert settings.DEVELOPMENT
         UserMessage.objects.all().update(flags=F("flags").bitand(~UserMessage.flags.read))
-        cache._cache.flush_all()
+        _cache = getattr(cache, "_cache")
+        assert isinstance(_cache, bmemcached.Client)
+        _cache.flush_all()