On 01/31, Derrick Stolee wrote:

Sorry for chiming in with mostly nitpicks so late since sending this
version. Mostly, I tried to read it to see if I could understand the scope
of the patch and how this code worked before. It looks very polished, so I
the nits were the best I could do.

On 1/25/2018 6:58 PM, Brandon Williams wrote:

quoted

Changes in v2:
  * Added documentation for fetch
  * changes #defines for state variables to be enums
  * couple code changes to pkt-line functions and documentation
  * Added unit tests for the git-serve binary as well as for ls-refs

I'm a fan of more unit-level testing, and I think that will be more
important as we go on with these multiple configuration options.

quoted

Areas for improvement
  * Push isn't implemented, right now this is ok because if v2 is requested the
    server can just default to v0.  Before this can be merged we may want to
    change how the client request a new protocol, and not allow for sending
    "version=2" when pushing even though the user has it configured.  Or maybe
    its fine to just have an older client who doesn't understand how to push
    (and request v2) to die if the server tries to speak v2 at it.

    Fixing this essentially would just require piping through a bit more
    information to the function which ultimately runs connect (for both builtins
    and remote-curl)

Definitely save push for a later patch. Getting 'fetch' online did require
'ls-refs' at the same time. Future reviews will be easier when adding one
command at a time.

quoted

  * I want to make sure that the docs are well written before this gets merged
    so I'm hoping that someone can do a through review on the docs themselves to
    make sure they are clear.

I made a comment in the docs about the architectural changes. While I think
a discussion on that topic would be valuable, I'm not sure that's the point
of the document (i.e. documenting what v2 does versus selling the value of
the patch). I thought the docs were clear for how the commands work.

quoted

  * Right now there is a capability 'stateless-rpc' which essentially makes sure
    that a server command completes after a single round (this is to make sure
    http works cleanly).  After talking with some folks it may make more sense
    to just have v2 be stateless in nature so that all commands terminate after
    a single round trip.  This makes things a bit easier if a server wants to
    have ssh just be a proxy for http.

    One potential thing would be to flip this so that by default the protocol is
    stateless and if a server/command has a state-full mode that can be
    implemented as a capability at a later point.  Thoughts?

At minimum, all commands should be designed with a "stateless first"
philosophy since a large number of users communicate via HTTP[S] and any
decisions that make stateless communication painful should be rejected.

I agree with this and my next version will run with this philosophy in
mind (v2 will be stateless by default).

quoted

  * Shallow repositories and shallow clones aren't supported yet.  I'm working
    on it and it can be either added to v2 by default if people think it needs
    to be in there from the start, or we can add it as a capability at a later
    point.

I'm happy to say the following:

1. Shallow repositories should not be used for servers, since they cannot
service all requests.

2. Since v2 has easy capability features, I'm happy to leave shallow for
later. We will want to verify that a shallow clone command reverts to v1.


I fetched bw/protocol-v2 with tip 13c70148, built, set 'protocol.version=2'
in the config, and tested fetches against GitHub and VSTS just as a
compatibility test. Everything worked just fine.

Is there an easy way to test the existing test suite for clone and fetch
using protocol v2 to make sure there are no regressions with
protocol.version=2 in the config?

Yes there already exist interop tests for testing the addition of
requesting a new protocol at //t/interop/i5700-protocol-transition.sh

Thanks,
-Stolee

-- 
Brandon Williams