Changing IMAP separator - does it break things?

[Sami Ketola]

> On 14. Oct 2020, at 14.20, @lbutlr <kremels at kreme.com> wrote:
> 
> On 14 Oct 2020, at 04:24, Sami Ketola <sami at ketola.io> wrote:
>> On 14. Oct 2020, at 12.51, Victor Sudakov <vas at sibptus.ru> wrote:
>>> Those Mac clients who do not use nested folders do not seem to be
>>> affected. That is, I've already suggested to the Mac Mail user that he
>>> start Thunderbird, move all his mailboxes into the IMAP root folder, and
>>> then go on using Mac Mail. I hope that's what he has done.
> 
>> There is a bug in Mail.app that it always assumes / as hierarchy separator and 
>> completely ignores server provided separator.
> 
> Cite? Because no, that is not my experience at all.
> 
> From my maildir on my FreeBSD server:
> 
> # ls -lnd .root*
> drwx------  5 89  89  512 Oct 14 05:16 .root
> drwx------  5 89  89  512 Oct 14 02:02 .root.44
> drwx------  5 89  89  512 Oct 14 02:02 .root.Cron
> drwx------  5 89  89  512 Oct 14 05:16 .root.Hastur
> … etc
> 
> Works fine in Mail.app on Mac OS and has for at least 16 years.

I just tested it with my Dovecot 2.2.36 setup. I did set up an account with '.' as separator and created some folders.
First mail.app succeeded in creating test root folder but when I tried to create subfolder 'test2' under 'test' Mail.app issued
CREATE "test/test2" folder instead of "test.test2". And then failed to list the created folder completely.

Everything worked if I did set separator to '/'

Sami