Woops, this time with better formatting.

Hello there

We stumbled upon an user account with Solr FTS, which returned no search results for any given search query.
Further investigation revealed an issue between indexing mails and querying the index.
The user name contains upper and lower case characters (eg. Some.User@domain.net).

When new mail is indexed for this user, the user name used for Solr's `user` and `id` fields are transformed into lowercase, as shown in the Solr log:

webapp=/solr path=/update params={...}{add=[8543/426f3b0348d03451a3fb00008ba2b673/some.user@domain.net (1724281617442144256), ... (162 adds)]} 0 44298

And can be confirmed by manually querying Solr. The Solr schema in use performs no transformation for the affected fields.

When a search request is performed via IMAP, Dovecot queries Solr with the original user name:

GET /solr/dovecot_fts_popimap/select?wt=json&f...&fq=%2Bbox:1a30ec359dce3451b8e600008ba2b673+%2Buser:Some.User@domain.net HTTP/1.1"

Which (correctly) returns zero results.

To summarize, I suspect dovecot transforms any user name to lower case while indexing mails, but not when querying for results.

Is this a bug, or caused by misconfiguration?

Regards
Patrik