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From Bikas Saha <bi...@hortonworks.com>
Subject RE: [DISCUSS] Developing features in branches
Date Thu, 30 Apr 2015 17:12:00 GMT
IMO,

Branch development is great when the feature is "blue sky" - we don't exactly know what we
are going to do. We will try out things and the current state will be unstable for a while
until we have figured things out.

On master, the work would be clearly spec'd out and done without causing disruption. So I
am guessing, branches could be used when the feature is expected to be more "blue sky". Of
course that's a subjective call.

Bikas

-----Original Message-----
From: Zhijie Shen [mailto:zshen@hortonworks.com] 
Sent: Wednesday, April 29, 2015 9:43 PM
To: yarn-dev@hadoop.apache.org
Subject: Re: [DISCUSS] Developing features in branches

My 2 cents:

Branch maintenance cost should be fine if we have few features to be developed in branches.
However, if there're too many, each other branch may be blind to most of latest code change
from others, and trunk/branch-2 becomes stale. That said, with the increasing adopting of
branch development, it's likely to increase the cost of merging each branch back.

Some features may last more than one releases, such as RM restarting before and timeline service
now. Even if it's developed in a branch, we may want to merge its milestones such as phase
1, phase 2 back to trunk/branch-2 to align with some release before it's completely done.
Moreover, my experience is that the longer a feature stays in the branch, the more conflicts
we have to merge. Hence, it may not be a good idea to hold a feature in the branch too long
before merging it back.

Thanks,
Zhijie
________________________________________
From: Subramaniam V K <subru.vk@gmail.com>
Sent: Wednesday, April 29, 2015 7:16 PM
To: yarn-dev@hadoop.apache.org
Subject: Re: [DISCUSS] Developing features in branches

Karthik, thanks for starting the thread.

Here's my $0.02 based on the experience of working on a feature branch while adding reservations
(YARN-1051).

Overall a +1 for the approach.

The couple of pain points we faced were:
1) Merge cost with trunk
2) Lack of CI in the feature branch

The migration to git & keeping the feature branch in continuous sync with trunk mitigated
(1) and with Allen's new test-patch.sh addressing (2), branches for features especially if
used for all major features seems like an excellent choice.

-Subru

On Tue, Apr 28, 2015 at 5:47 PM, Sangjin Lee <sjlee0@gmail.com> wrote:

> Ah, I missed that part (obviously). Fantastic!
>
> On Tue, Apr 28, 2015 at 5:31 PM, Sean Busbey <busbey@cloudera.com> wrote:
>
> > On Apr 28, 2015 5:59 PM, "Sangjin Lee" <sjlee0@gmail.com> wrote:
> > >
> >
> > > That said, in a way we're deferring the cost of cleaning things up
> > towards
> > > the end of the branch. For example, we don't get the same 
> > > treatment of
> > the
> > > hadoop jenkins in a branch development. It's left up to the group 
> > > or
> the
> > > individuals to make sure to run test-patch.sh to ensure tech debt 
> > > does
> > not
> > > accumulate.
> >
> > As Allen previously mentioned, the QA bot will run test-patch 
> > against feature branches so long as you name the patch file correctly.
> >
>

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