State of protocol changes; naming contest

[Augie Fackler]

On Feb 20, 2010, at 9:24 AM, Sune Foldager wrote:

> Hey guys
> 
> As you may know I have been working on some changes to the two write
> protocols (low-level changes; not command set), ssh and http to bring
> their feature set more in-line. Http is missing better transfer of
> hook-output and sometimes errors back to the client; ssh is missing
> arbitrary number of arguments for commands.
> 
> Also, we want to add some features to the high-level protocol in the
> near future: parent-delta, light-weight copy, new discovery. For these
> things we are going to need some capabilities, so the client knows what
> the server understands. For some things we also need a few other tweaks
> which are not finalized yet.
> 
> The protocol changes for ssh necessitates a new capability on two
> levels: low-level (the command format changes) and high-level (the
> features mentioned above). The http protocol only needs capabilities for
> the high-level changes, since the command format stays the same. Thus we
> have the following decisions to make:
> 
> a) Do we use the same capability names for ssh and http? I personally
> think we should.

+1

> 
> b) Do we use separate capabilities for each of the high-level features,
> or lump them together in a single one? I think I prefer the latter, to
> avoid making the code too complex.

I'd prefer the former, as it opens the door to having a server only support some of them if (for example) they're expensive to compute and it's a heavily-loaded server.

> c) Do we use a separate capability for the new ssh command format, or
> lump it together with the one from b (assuming we decided to lump those
> together; otherwise we need a separate one I guess). I am not sure about
> this one. It's somewhat a conflation of domains. On the other hand, we
> don't really need the feature on its own.

I think it makes sense as its own capability.

> d) What do we call the capabilities? Some possibilities: "protocol=2"
> (pro: easy to extend later on. con: kind of conflicts with the 0.1 that
> http uses, but which isn't _really_ used). "<foo>ng" (this one's for
> mpm). "lwpddisco".. ok that's silly, but illustrates how hard it is to
> find a suitable name :).
> 
> Let's have some feedback on the above points :)
> 
> /Sune
> _______________________________________________
> Mercurial-devel mailing list
> Mercurial-devel at selenic.com
> http://selenic.com/mailman/listinfo/mercurial-devel