Branching strategy - Feature vs Release

Hi All

We're having a big debate where I work over whether or not to use the
"release" based branching strategy, or the "feature" based way.

I've always worked with the latter. These are the reasons why:

1) Trunk is always stable. This always mimics exactly what's in
production.

2) I do all new work on a branch (whether it's a small
experimental change or a new release which is essentially a collection
of new features). This to me has the following additional advantages

a. My new changes don't affect the production codebase

b. When the customer who requested change X wants it to go live, I
can merge it in to the trunk (because its own isolated branch), and
release only that change (plus whatever was in trunk originally). I then
commit it, tag it, and hey presto, trunk still mimics production
exactly. With the release based approach, with everyone committing
different changes to the trunk, when a customer wants change X to go
live, I have to tell him that it can go live, but I have to tell another
customer that because I have to release X, his change Y must also go
live too. This situation might never occur with systems that have a
simple release lifecycle, but when you're dealing with large systems
with different sets of customers (especially if they have different
legal requirements, or they are in different countries) I think this is
really important.

The arguments against this approach are often:

1) Merging is hard. I don't like it

a. Well, in my experience with Subversion and CVS, merging is
actually quite easy. I might have a few conflicts to resolve every now
and again, but they are usually pretty easy to iron out, especially if I
keep my branch up to date with the trunk (which might have had some bug
fixes done to it over time)

2) Keeping track of lots of branches is hard.

a. Not really. If I use a good naming convention, a handful of
branches are easy enough to keep track of. It's not as if I'm going to
have hundreds of branches to worry about, in reality

3) We have release branches so you know exactly whats on a
production server

a. So does this approach - whatever is on the trunk is in
production. And, a release branch by definition changes over time (until
it's tagged as final after which there will still be an element of
merging involved to get it in sync with the development branch (trunk in
this case)).

I can see why people would favour the release branch strategy, because
it 'sounds' much simpler, but I think the benefits of the feature based
approach far outweigh the negatives. I expect a lot of people to
disagree with me, but it's a good debate and I'd welcome any comments.

Thanks

Richard

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Received on Wed Nov 8 11:08:33 2006