[Dovecot] case (non-)sensitivity for folder names

[Timo Sirainen]

On 5.1.2011, at 23.04, Phil Howard wrote:

> But if for INBOX names are case IN-sensitive, then there will be
> confusion because anything obeying that concept would see "Inbox >>
> spam" and "Inbox >> Spam" as being the same box.

It's case insensitive only for the INBOX itself, not its children. So INBOX.spam and inbox.spam are the same, but INBOX.Spam isn't the same as either of them.

> The behavior I have seen, through Evolution (I just installed
> Thunderbird and will be trying that in a while), is that when I had 3
> existing, "foo", "Foo", and "FOO", all under inbox (seen as ".INBOX"
> on the server, and as "Inbox" in the client), there were various
> situations of getting things mixed up among them as if accessing one
> would really access another, though it was unclear which.  But I
> definitely ran into the case where when I had ONE message in each of
> "foo", "Foo" and "FOO", and deleted the message in "foo" only, it
> deleted one message in all three, but left the new message count on
> "FOO" as "(1)" even though it showed now messages.

I'm pretty sure this confusion comes from Evolution internally.

> My boss was using Apple Mail, then tried Thunderbird, and similar
> effects are happening.  I'm wanting to believe that IMAP is just so
> poorly defined that everyone is doing things just a bit differently,
> and enough to sort of work, but mess things up.

It's possible that multiple clients do case insensitive comparing. I doubt many people have actually tested what happens then. I only know Dovecot's code, and there's about zero possibility of it mixing up mailboxes with different casing.