[MlMt] expiring deleted and sent

[Bill Cole]

On 8 Oct 2018, at 13:52, Randy Bush wrote:

>> A user NEVER directly adds a message to a Smart Mailbox.
>
> but i delete and send mail, and it is Deleted and Sent i have 
> configured
> to delete older

I am working on the assumption that Deleted and Sent are real IMAP 
mailboxes in your account ("Source" mailboxes, in MM jargon,) which is 
why you need to create Smart Mailboxes as I described to make the 
expiration actually happen.

>> The combined criteria of the Source Mailboxes plus the Conditions add
>> messages to a Smart Mailbox.
>
> clearly i do not understand how a smart mailbox is different than a
> stupid one

Smart Mailboxes are logical constructs that have no existence outside of 
a logical definition in your MailMate configuration and how MailMate 
presents a collection of matching messages to you. They don't exist as a 
set of message files in a Maildir directory or as messages concatenated 
into a mbox file or any other mechanism of bundling stored messages 
together. The IMAP server knows nothing of Smart Mailboxes and neither 
does MM's local message cache.

The IMAP server has a hierarchical tree of mailboxes that MailMate 
refers to as Source Mailboxes and MailMate stores all messages in a 
cache that mirrors the IMAP hierarchy. The user or a MailMate rule can 
move messages arbitrarily between Source Mailboxes (and that movement is 
passed upstream to the IMAP server) but Smart Mailboxes contain messages 
based only on their logical definition consisting of Source Mailboxes 
and Conditions. You can't drag a message to a Smart Mailbox or use the 
"Message->Move to Mailbox..." to move a message into a Smart Mailbox, 
you can only adjust the Source Mailboxes and Conditions to cause 
MailMate to select the matching messages.

Complicating matters, MM also presents unified special-purpose mailboxes 
containing the aggregation of messages from the special-purpose 
mailboxes across all IMAP accounts: Inbox, Sent Messages, Deleted 
Messages, Archive, Drafts, and Junk. These are akin to MM Smart 
Mailboxes but lack configurable Sources (which are selected by setting 
the "Mailbox Type" on Sources) and you probably should avoid the 
temptation of reducing their contents by adding Conditions. The 
mechanism I described depends on date-based Conditions to "add" messages 
to the operative mailboxes when they hit their expiration age, which is 
what triggers the deleting rule. Hence, it cannot be used with unified 
special-purpose mailboxes and requires one discrete Smart Mailbox for 
each set of expiration rules.