[PATCH 3/3] lib: Reject multi-message mboxes and deprecate single-message mbox

[Tomi Ollila]

On Sun, Nov 25 2012, Austin Clements <amdragon at MIT.EDU> wrote:

> Quoth Tomi Ollila on Nov 25 at  3:26 pm:
>> On Sun, Nov 25 2012, Austin Clements <amdragon at MIT.EDU> wrote:
>> 
>> > Previously, we would treat multi-message mboxes as one giant email,
>> > which, besides the obvious incorrect indexing, often led to
>> > out-of-memory errors for archival mboxes.  Now we explicitly reject
>> > multi-message mboxes.  For historical reasons, we retain support for
>> > single-message mboxes, but official deprecate this behavior.
>> 
>> 
>> The series looks good to me -- but I don't know about deprecating
>> single-message mboxes:
>> 
>> * If we someday support (read-only?) mbox format, then single-message
>>   mboxes are "normal" again.
>
> If notmuch does gain mbox support, then its handling of single-message
> mboxes will *definitely* change because it will stop doing
> maildir-like things to them (flag sync, moving from new to cur, etc),
> which people may currently be depending on.  This was one of the
> motivations for deprecating the current handling of single-message
> mboxes.
>
>> * Some naïve mb2md scripts could leave the 'From ' -line intact: for
>>   example `formail -bz -s head -3 < $MAIL`(*) can be used to demonstrate this
>
> I would call that "buggy", rather than "naïve".  ]:--8)
>
>> * Some people may have large collection of single-file messages starting
>>   with 'From ' currently indexed. If those are to be re-indexed later
>>   without "single-message mbox" support that is somewhat of a burden to
>>   the users (**)
>
> That's why this only deprecates them (with a warning) and doesn't drop
> support for them.  The idea is to keep the historical handling for a
> few releases and then we'll have the flexibility to do what we want
> with single-message mboxes (including supporting them as real mbox).
>
> It's probably a good idea to include a script or a wiki pointer for
> fixing single-message mboxes in the NEWS.  As long as the file name is
> kept the same, notmuch won't reindex it.

Ok, I'm convinced. +1

Tomi

>
>> (*) my "mb2md" wannabe does gnus-like "$formail" -bz -R 'From ' X-From-Line: ...
>> 
>> (**) Something like the following could be used to mangle "single-file mboxes"...
>>      find . -type f | xargs perl -e 'foreach (@ARGV) { open IO, "+<", $_ or
>>      next; sysread IO, $buf, 5; if ($buf eq "From ") { sysseek IO, 0, 0;
>>      syswrite IO, "Fro:"; }}' 
>>      This breaks the multi-message mbox nicely... >;)
>> 
>> 
>> Tomi
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