[PATCH 2 of 8] discovery: move code for creating outgoing from heads and common (API)

[Pierre-Yves David]

On 08/05/2016 05:16 AM, Gregory Szorc wrote:
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1470365488 25200
> #      Thu Aug 04 19:51:28 2016 -0700
> # Node ID 19d16c9bce2fdf86d8c84915a45815bb7d4fd932
> # Parent  8a046444390debab5372de0b4f38863c57058f69
> discovery: move code for creating outgoing from heads and common (API)
>
> We recently moved similar code from changegroup.py to
> discovery.outgoingbetween(). It makes sense for creation of outgoing
> instances to all live together in discovery.py. So move
> changegroup.computeoutgoing() to discovery.outgoingheadsandcommon() and
> update consumers to use the new function.

I like the general idea of cleaning the changegroup API. but I think we 
can move toward something even saner:

With your series we end up with 3 way to obtains an outgoing object

- outgoingbetween(repo, roots, heads)
   # root can be empty//False

- outgoingheadsandcommon(repo, heads, common)
   # common will be filtered from locally missing
   # heads can be empty (means all heads)

- outgoing(revlog, commonheads, missingheads):

That is probably 2 more function than we want.

First, even if the object will only bear a changelog object, all 
creators seems to have access to a repository anyway. So we can probably 
make the class internal and have all caller go through a builder function.

Second, we can probably have a single function handling all this with 
default value:

- outgoing(repo, roots=None, commonheads=None, heads=None)
   # 'roots' and 'commonheads' cannot be both specified
   # if neither 'roots' or 'commonheads' is set, 'commonheads' is nullid
   # commonheads is filtered if specified
   # heads=None mean 'all heads in the repo

In my opinion having a single high level API would make things much simpler.

-- 
Pierre-Yves David