Williams: Introducing Git protocol version 2

[Posted May 18, 2018 by corbet]

Brandon Williams writes about the new Git remote protocol that will debut in the 2.18 release. "We recently rolled out support for protocol version 2 at Google and have seen a performance improvement of 3x for no-op fetches of a single branch on repositories containing 500k references. Protocol v2 has also enabled a reduction of 8x of the overhead bytes (non-packfile) sent from googlesource.com servers. A majority of this improvement is due to filtering references advertised by the server to the refs the client has expressed interest in."

Williams: Introducing Git protocol version 2

Posted May 19, 2018 19:05 UTC (Sat) by xtifr (guest, #143) [Link] (2 responses)

The description of the hack they had to come up with to work around built-in limitations caused by earlier oversights, compounded by bug-fixes, is both frightening and awe-inspiring.

I hope *someone* learned a lesson about designing wire protocols (or protocols in general) without any versioning info to start with.

Williams: Introducing Git protocol version 2

Posted May 19, 2018 22:08 UTC (Sat) by brunowolff (guest, #71160) [Link] (1 responses)

It's not always that simple. Downgrade attacks are a common security flaw.

Williams: Introducing Git protocol version 2

Posted May 22, 2018 8:22 UTC (Tue) by Karellen (subscriber, #67644) [Link]

So... if an inherent security flaw is found in version 1 of a protocol, and users are stuck on version 1 forever because there is no way specify that there even is a version 2 of the protocol to upgrade to, how is that better?