RFC: JDK 9 Sandbox Forest Proposal

[Volker Simonis]

On Mon, Sep 22, 2014 at 10:35 PM, Joe Darcy <joe.darcy at oracle.com> wrote:
> I agree with Mike's assessment below: while this proposal as it stands may
> not directly support all desirable modes of working (branches spanning
> forests), it greatly simplifies many should-be-common ways of sharing and
> working on code.
>
> I'd like to see us quickly go forward with this proposal, gain some
> experience with it, and then assess what adjustments might be helpful after
> a few months.

Agree.

>
> One reason I'd like to see the JDK organization uses branches for this
> project is so that branches could be included in our toolbox of features to
> use for multi-release work.
>
> For example, I think it could be helpful if the 9 update releases were
> implemented in terms of branches in a 9 update forest, as opposed to the
> practice today in the JDK 8 update world where for a few months each release
> gets its own forest that is then soon abandoned after a few weeks. This
> could also enable the Hg tooling to be used to answer questions like "which
> update releases is this fix in?" rather than relying almost exclusively on
> the bug database for that information.

I fully agree that using new new forest for each update release isn't
that nice. But in some sense it's quite safe. I'm not sure if it's
possible to "close" a certain branch to prevent people from pushing
there unintentionally if we would use branches for each update
release. And we need some easy way to bring all repos in the forest to
the same branch so people don't accidentally build OpenJDK from
different branches.

So let's start testing branches on the sandbox repo to gain some experience:)

>
> Cheers,
>
> -Joe
>
>
> On 9/22/2014 12:28 PM, Mike Duigou wrote:
>>
>> On Sep 22 2014, at 01:38 , Volker Simonis <volker.simonis at gmail.com>
>> wrote:
>>
>>> On Sun, Sep 21, 2014 at 4:41 PM, David Chase <david.r.chase at oracle.com>
>>> wrote:
>>>>>
>>>>> - All development happens on branches.
>>>>
>>>> It would be lovely to have a short tutorial on how we do
>>>> this written up and put in an easy-to-access place.
>>>> Branching still makes me nervous.
>>>>
>>> I'm also not familiar with branches. How do branches work in a
>>> Mercurial forest? Is it possible to easily develop on a branch if you
>>> need to push to different repositories within the whole sandbox forest
>>> (i.e. hotspot and jdk). Is it somehow possible to enforce the smae
>>> branch on all the repos in a forest?
>>
>> There is no specific support for branching across forests. This will need
>> to be managed manually unless extensions like trees [1] can be adapted to do
>> the necessary management across all repos.
>>
>>> I agree that the OpenJDK project
>>> process is much too heavyweight for many smaller project, but in the
>>> end you always get a complete forest. I'm just curious if cross
>>> repository changes can be easily developed with branches.
>>
>> Though you do end up with a complete forest most patches/features only
>> make changes in a single repo. For some people YMMV significantly of course.
>> I expect that most people will only need to work with a single repo.
>>
>> Mike
>>
>> [1] http://hg.openjdk.java.net/code-tools/trees/raw-file/tip/trees.py
>>
>>
>>> Thanks,
>>> Volker
>>>
>>>> David
>>>>
>