Comment 76 for bug 1074260

(In reply to Kent James (:rkent) from comment #66)
> Comment on attachment 679311
> Update message size in database on every full message download
>
> I've tested this on Erik's account, and others have tested it, and it seems
> to work. Code looks good as well.

Did you also test for the case where folder data is NOT cached for offline use?
In the past, there have been issues causing corruption of attachments when offline caching
is not used.
For example, receive a mail message with a largish attachment, read only the text part (attachments are never downloaded), then forward the whole message including attachment to another address. Receiver gets only "This part will be downloaded on demand" instead of attachment.
Other example: receive message that fulfilled the criteria for the bug discussed here to cause repeated downloading, but in a folder that has offline caching disabled. Open attachments. Attachments are corrupt.

Those errors resurfaced at the same time the issue discussed in this bug appeared, and
showed the same phenomena (like a wrong message size in the message list, a repair of the folder temporarily fixing it). I think it is the same bug but manifested in a different way because of the different setting of offline caching.