fix(share): Return empty string if no label is set

[susnux]

• Resolves: [Bug]: Sharing links with null labels broken after upgrade to NC-30 #48629

Summary

While the database supports NULL, the typing has always said it only returns string. So to not break any apps that might trust the typings we should return '' if the database is set to NULL.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[susnux]

/backport to stable30

[provokateurin]

Oh then you can actually revert #47551 where I thought this was intended but wrongly documented!
It was already broken before 30 as well, so please backport to 29 and 28 as well.

[susnux]

Oh then you can actually revert #47551 where I thought this was intended but wrongly documented!

I am not sure. The PHP documentation is only stating strings, but the DB accepts null. I personally think null is much better for representing the empty label then an empty string. But then again we would break some usage of the API if you trust the doc comments.

[come-nc]

I thought some DB will treat null and empty string the same anyway and so we cannot differentiate in DB, no?

[provokateurin]

Yeah, Oracle treats empty strings as NULL.
While I agree that it is nicer in the API to use null for a missing label we should fallback to an empty string to always have consistent behavior.

[susnux]

Oh then you can actually revert #47551 where I thought this was intended but wrongly documented!

Done

[susnux]

/backport to stable29

[provokateurin]

@susnux not 28?

[susnux]

/backport to stable28