[3.0] Can not send PMs

[jdarwood007]

When I try to send a message

 Class "SMF\PersonalMessage\UserDataset" not found 

I think also the type and search for a name is broken as it doesn't complete like it does for 2.1. Maybe related

[albertlast]

Cause found, fix in #9342.

Sources/PersonalMessage/PM.php uses UserDataset::Minimal and UserDataset::None at lines 1607, 1670 and 1917 but never imports the enum. The file's own namespace is SMF\PersonalMessage, so the unqualified name resolves there instead of to SMF\UserDataset. PM::send() reaches User::load($all_to, dataset: UserDataset::Minimal) while loading the recipients and dies, so the message is never stored. One line: use SMF\UserDataset;.

Verified before and after on a fresh 3.0 install: before, the send produced the error page with smf_personal_messages unchanged; after, the PM is delivered and the sender lands on the inbox with done=sent.

On the second half of the report — the name field not completing the way 2.1 does — that part does not reproduce on current release-3.0. Typing into the To field returns an auto_suggest_div populated from action=suggest, and picking the name works. If it is still happening for you it looks like something separate from this, and a browser console error from that page would help.

Despite the similar wording, this is not the same as #9336. That one is Cannot assign null to property SMF\User::$dataset, a null being assigned to a property whose type resolves fine; this one is the class not being findable at all.