[dovecot/core] a97ad3: lib-storage: Fix sorting mails with the same prima...

[GitHub]

  Branch: refs/heads/master-2.2
  Home:   https://github.com/dovecot/core
  Commit: a97ad32c8534cc8fcfb359767f880789cb695124
      https://github.com/dovecot/core/commit/a97ad32c8534cc8fcfb359767f880789cb695124
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-11-28 (Tue, 28 Nov 2017)

  Changed paths:
    M src/lib-storage/index/index-sort-string.c

  Log Message:
  -----------
  lib-storage: Fix sorting mails with the same primary sort key

The sorting order may have been wrong when there was a combination of:
 * Messages were sorted by a string (e.g. Subject)
 * Some messages had the same sort key (e.g. same base subject)
 * Within the messages with the same sort key, some of the messages already
   had the "sort-*" index number in Dovecot indexes, but some of them
   didn't.

The result was that Dovecot found that the two messages had exactly the same
sort key. It should have continued with the secondary sort key (e.g.
message sequence number), but it didn't.