Fixes an issue of using empty username when searching

[DummyCatz]

Fixes an issue of using empty username when searching

[filiphanes]

thanks
In what situation was empty username problem?

[DummyCatz]

thanks In what situation was empty username problem?

The public mailboxes don't have owners, so the usernames are empty in this case.

[filiphanes]

Why did you choose -?

Could it be solved by changing elastic schema to allow empty user?

I think when user is empty it should be empty or null not short string.

[filiphanes]

try setting null_value in elastic schema:
"user": {"type": "keyword", "normalizer": "lowercase", "null_value": ""},

[filiphanes]

fts-elastic uses parameter routing=user for faster connection to shard with user's mails.
How should it work in public mailboxes?