Issue Summary

Confluence Space permissions REST API (/rest/api/space/<SPACEKEY>/permissions) results in an HTTP 500 response when the space permissions in the Knowledge Base of the JSM (connected to Confluence) project is set to 'All Users and Customers'.

Steps to Reproduce

1. Create an application link (with impersonation) between Confluence v9.2.1 and JSM v10.5.0.
2. Create a project example- 'test' in the JSM.
3. Create a Space in Confluence example- 'GLOB'
4. In the JSM project 'test', link the 'GLOB' space and set to 'All users and customers' as below:

5. Call the rest API for space permissions

<Base_URL>/rest/api/space/spacekey/permissions 

Expected Results

User/admin Should be able to fetch space permissions

Actual Results

Space permissions Rest api throws 500, Internal server error

Workaround

Change the permissions to only Licensed users in JSM for that linked space.

Note: The permissions in the Confluence database do not change when switching the JSM permissions between 'All users and customers' and 'Only License Users', which was verified using the below DB query.

select sp.permid, sp.permtype, sp.spaceid, s.spacekey, sp.permusername, u.username
from spacepermissions sp
join spaces s on s.spaceid = sp.spaceid
join user_mapping u on u.user_key = sp.permusername
where spacekey = '<Space_Key>'

• The REST API (/rest/api/space/<SPACEKEY>/permissions) doesn't seem to refer to the space permissions table.
  This could be because the JSM's feature Give Access to Unlicensed Users from Jira Service Management is overwriting the default Space permissions.
• A similar issue was reported in the CONFSERVER-98372. However, the issue in CONFSERVER-98372 occurs when the permissions gets modified on the Database, which is not the case here.