[MlMt] Resetting per-mailbox column state

[Bill Cole]

On 14 Aug 2014, at 7:11, Benny Kjær Nielsen wrote:

> On 13 Aug 2014, at 20:52, Bill Cole wrote:
>
>> I expect Benny will give me a proper slapping if this is 
>> substantially wrong, but I think this is worth sharing since I wasted 
>> a few hours trying to find a better fix for what is probably the 
>> result of a scale-sensitive bug.
>
> I'm sorry you had to spend time on this. I know there is a bug 
> somewhere in this system, but I don't know what triggers it. Under 
> certain circumstances MailMate starts to ignore changes to mailbox 
> related display settings.

I have a vague hypothesis based on the fact that my attempts to do 
targeted pruning of the giant MmMailboxRelatedStates dict yielded 
erratic results and small variances in what MM left in it after 
quitting. Across 16 snapshots, 249 mailboxes had entries in all, 261 
different mailboxes had entries in at least one, and all contained 260 
or 261 entries. Maybe some array of entries uses an 8-bit index? Seems 
unlikely, but only you could figure that out.


> Your reset-trick is correct and should be safe to use except for the 
> loss of settings of course:
>
>> 	defaults delete com.freron.MailMate MmMailboxRelatedStates
>
> Let me know if you find a way to get MailMate back into the buggy 
> state. (There is a possibility that this is only seen by long time 
> users with old settings files — in other words, it might not be 
> reproducible after the fix above.)

Long time users or perhaps users who have large numbers of mailboxes.

It seems like that pile of per-mailbox settings objects must grow almost 
strictly monotonically, as there's no obvious way to fully default a 
mailbox and do away with the need for its specific settings. Without a 
dedicated GC cycle to minimize it, a bloated & broken 
MmMailboxRelatedStates may be inevitable for anyone with a large mailbox 
count.