Re: LARGE_PACKET_MAX wrong?
From: Jeff King <hidden>
Date: 2016-07-26 13:43:39
On Tue, Jul 26, 2016 at 03:07:41PM +0200, Lars Schneider wrote:
I am reading the pkt-line code and stumbled across this oddity: LARGE_PACKET_MAX is defined as 65520 https://github.com/git/git/blob/8c6d1f9807c67532e7fb545a944b064faff0f70b/pkt-line.h#L79 In `format_packet` we check that the 4 bytes of length data plus payload is not larger than LARGE_PACKET_MAX (= 65520) https://github.com/git/git/blob/8c6d1f9807c67532e7fb545a944b064faff0f70b/pkt-line.c#L111-L112 However, in the documentation we state that 4 bytes of length data plus payload must not exceed 65524 https://github.com/git/git/blob/8c6d1f9807c67532e7fb545a944b064faff0f70b/Documentation/technical/protocol-common.txt#L70-L72 Who is right? Code or documentation?
I think the documentation is wrong. Git's packet_read() will complain on a 65524-byte incoming packet (it actually handles up to 65523, but that is simply a quirk of the implementation). The sending sides always include the 4-byte header in the LARGE_PACKET_MAX calculations. So I don't know what was intended once upon a time, but I think we have to stick to what the code does, because there are many deployed instances that we cannot break compatibility with. -Peff