Insert failing in without sharing class for a manual share record

Question

I am inserting a manual share record for a custom object (Request__c) and getting the error: "Insert failed... insufficient access rights on cross-reference id: []".

When I comment out the insertion of the Request__share record the error does not occur so I know it's specific to that insert. The class is running without sharing. The user performing the action has access to the relevant record type on the Request__c object. I debugged all the variables being used to create

Any ideas what might be causing the insert to fail? I feel like it may be security related, but I'm not sure how to check what permissions are needed to insert a Request__share record. It's running without sharing so I'm not sure what the issue could be.

Relevant code:

sharingToCreate.add(new Request__Share(
                    AccessLevel = 'Read',
                    RowCause = 'Manual',
                    ParentId = requestId,
                    UserOrGroupId = piwi.ActorId
));

insert sharingToCreate;

Answer 1

As noted by the OP, the running user is a High Volume Customer Portal user. These users have restrictions on sharing as outlined in About High-Volume Community or Site Users

• High-volume users can’t manually share records they own or have access to.
• Only share the records they own with authenticated Salesforce users in Share Groups
• Only share the records they own in guest user or criteria-based sharing rules

You'll need to check the running user's UserType and avoid the insert ...

if (UserInfo.getUserType() == 'CSPLitePortal') {..do nothing..}

Apex ref