There is a bug in partial IMAP fetches where the following happens:

fetch ... <0.10240>	correctly returns bytes 0-10239
fetch ... <10240.10240>	incorrectly returns bytes 20479...
fetch ... <10240.10240> (a 2nd time)	correctly returns bytes 10240-20479

While the second fetch fails, the third fetch works correctly. I tracked this down to a problem with partial_cache. There seems to be a bug in lib-mail/message-send.c:39 (CVS):

    ret = o_stream_send_istream(output, input) > 0;

This causes message_send() to return 0 or 1 (note the "> 0"), not the number of bytes sent. This in turn causes partial.pos.virtual_size to get a value of 1 rather than 10240 in fetch_body(), and this in turn results in the wrong portion of the message being returned for the subsequent fetch.

But then when I remove the "> 0" from the above line of code, I get off-by-one errors:

fetch ... <0.10240>	correctly returns bytes 0-10240
fetch ... <10240.10240>	incorrectly returns bytes 10241-20480
fetch ... <10240.10240> (a 2nd time)	correctly returns bytes 10240-20479

I'm guessing there is a bug in the interaction with message_skip_virtual(), but I haven't been able to find the problem yet.

Any ideas? I've attached the offending message.

Matt