Folders not shown - Error 500 - unavailable federated share

[StCyr]

Expected behaviour

Application shows all my folders

Actual behaviour

Application only shows my favorites and, an error is shown "500: Internal server error".

I believe this issue is also the cause of various slowdowns in my application

Steps to reproduce

1- create a share on serverA and share it with serverB
2- once confirmed the share is accessible on serverB and synchronised on your iOS client, shutdown serverA

Additional information

The following log line appears on the server's log when I open my iOS app:

{
  "reqId": "CAQq2Zh6BXg4h7K4M4uy",
  "level": 0,
  "time": "2020-07-14T12:15:17+00:00",
  "remoteAddr": "94.104.124.217",
  "user": "cyrille",
  "app": "webdav",
  "method": "PROPFIND",
  "url": "/remote.php/webdav/",
  "message": "{\"Exception\":\"OCP\\\\Files\\\\StorageNotAvailableException\",\"Message\":\"\",\"Code\":1,\"Trace\":[{\"file\":\"/var/www/nextcloud/lib/private/Files/Storage/Wrapper/Availability.php\",\"line\":243,\"function\":\"checkAvailability\",\"class\":\"OC\\\\Files\\\\Storage\\\\Wrapper\\\\Availability\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/Storage/Wrapper/Wrapper.php\",\"line\":226,\"function\":\"file_exists\",\"class\":\"OC\\\\Files\\\\Storage\\\\Wrapper\\\\Availability\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/View.php\",\"line\":1334,\"function\":\"file_exists\",\"class\":\"OC\\\\Files\\\\Storage\\\\Wrapper\\\\Wrapper\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/View.php\",\"line\":1383,\"function\":\"getCacheEntry\",\"class\":\"OC\\\\Files\\\\View\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/Node/Root.php\",\"line\":201,\"function\":\"getFileInfo\",\"class\":\"OC\\\\Files\\\\View\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/Node/Folder.php\",\"line\":138,\"function\":\"get\",\"class\":\"OC\\\\Files\\\\Node\\\\Root\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/lib/private/Files/Node/Folder.php\",\"line\":147,\"function\":\"get\",\"class\":\"OC\\\\Files\\\\Node\\\\Folder\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/apps/text/lib/Service/WorkspaceService.php\",\"line\":28,\"function\":\"nodeExists\",\"class\":\"OC\\\\Files\\\\Node\\\\Folder\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/apps/text/lib/DAV/WorkspacePlugin.php\",\"line\":101,\"function\":\"getFile\",\"class\":\"OCA\\\\Text\\\\Service\\\\WorkspaceService\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/PropFind.php\",\"line\":96,\"function\":\"OCA\\\\Text\\\\DAV\\\\{closure}\",\"class\":\"OCA\\\\Text\\\\DAV\\\\WorkspacePlugin\",\"type\":\"->\",\"args\":[\"*** sensitive parameters replaced ***\"]},{\"file\":\"/var/www/nextcloud/apps/text/lib/DAV/WorkspacePlugin.php\",\"line\":107,\"function\":\"handle\",\"class\":\"Sabre\\\\DAV\\\\PropFind\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php\",\"line\":89,\"function\":\"propFind\",\"class\":\"OCA\\\\Text\\\\DAV\\\\WorkspacePlugin\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":1063,\"function\":\"emit\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":989,\"function\":\"getPropertiesByNode\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":1678,\"function\":\"getPropertiesIteratorForPath\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":1661,\"function\":\"writeMultiStatus\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php\",\"line\":363,\"function\":\"generateMultiStatus\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php\",\"line\":89,\"function\":\"httpPropFind\",\"class\":\"Sabre\\\\DAV\\\\CorePlugin\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":474,\"function\":\"emit\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":251,\"function\":\"invokeMethod\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php\",\"line\":319,\"function\":\"start\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/apps/dav/appinfo/v1/webdav.php\",\"line\":82,\"function\":\"exec\",\"class\":\"Sabre\\\\DAV\\\\Server\",\"type\":\"->\"},{\"file\":\"/var/www/nextcloud/remote.php\",\"line\":167,\"args\":[\"/var/www/nextcloud/apps/dav/appinfo/v1/webdav.php\"],\"function\":\"require_once\"}],\"File\":\"/var/www/nextcloud/lib/private/Files/Storage/Wrapper/Availability.php\",\"Line\":94,\"Hint\":\"Storage is temporarily not available\",\"CustomMessage\":\"--\"}",
  "userAgent": "Mozilla/5.0 (iOS) Nextcloud-iOS/3.0.0",
  "version": "19.0.0.12"
}

I suspect this issue is due to nextcloud/server#14797

Eventualy, after deleting the external share's corresponding row in table oc_share_external, the issue goes away

MariaDB [nextcloud]> select * from oc_share_external;
+----+--------+------------+---------------------------+-----------+-----------------+----------+-----------+-------+---------+------------+----------------------------------+----------+
| id | parent | share_type | remote                    | remote_id | share_token     | password | name      | owner | user    | mountpoint | mountpoint_hash                  | accepted |
+----+--------+------------+---------------------------+-----------+-----------------+----------+-----------+-------+---------+------------+----------------------------------+----------+
|  3 |     -1 |          0 | https://private.bollu.be/ |         3 | GL8M76GbVHk0nkv |          | /external | admin | cyrille | /external  | 48d7eb60b23e97e7d76b33e669c372da |        1 |
+----+--------+------------+---------------------------+-----------+-----------------+----------+-----------+-------+---------+------------+----------------------------------+----------+
1 row in set (0.000 sec)

MariaDB [nextcloud]> delete from oc_share_external where id=3;
Query OK, 1 row affected (0.019 sec)

Reasoning or why should it be changed/implemented?

This is a bug

iOS version

13.5.1

App version

3.0.0.76

Server configuration

Operating system:
Debian bullseye
Web server:
apache
Database:
MariaDB
PHP version:
7.4
Nextcloud version: (see Nextcloud admin page)
19.0

[mnme]

There is a thread in the Nextcloud community with several other people experiencing the same problem.