Re: [RFC/PATCH 0/5] protocol v2 for upload-pack

Johannes Sixt [off-list ref] writes:

You may also consider an idea I proposed here:

http://thread.gmane.org/gmane.comp.version-control.git/206886/focus=207342

The idea is that the exchange begins as usual, but when the v2 client
sees that the server also supports v2, then it begins sending its
desired refs. When the server notices that the client spoke while it
was still sending out its megabytes of ref advertisments, it stops the
v1 advertisements and continues with v2 protocol.

Yes, it would be possible to design the protocol in such a way
provided if we can find a v1 protocol message that we can use so
that a new client will send it as "I am a client capable of talking
the new protocol" and the message appears as a no-op to older
servers.  And that would allow us to transparently upgrade the
protocol in-line.  That would be a big plus.

And there seems to be such a message for both fetch and push
protoocol, as discussed in $gmane/264512 a few days ago.

But I think the current thinking is that it is OK to avoid the
ugliness and complexity of having to say "oops, sorry but I did not
hear your 'I am new enough' soon enough and sent a lot of v1
advertisement, let's resync with v2 protocol" and instead upgrade
the old client upon the _next_ exchange (see $gmane/264309).