Looking ahead: proposed Hg forest consolidation for JDK 10

[joe darcy]

Hi Maurizio,

A partial reply for now...


On 10/13/2016 6:21 AM, Maurizio Cimadamore wrote:
> Hi Joe,
> some comments on this.

[snip]

>
>
> On a separate and more <meta> note, it seems to me that this effort is 
> two things at once:
>
> * a repo consolidation: use a single repo instead of a forest
> * a source restructuring
>
> Each of the above moves has risks and costs for people in the OpenJDK 
> land. For instance, as discussed above, the repo consolidation might 
> mean significantly change the workflow people use on a daily basis 
> (see above). At the same time, the source restructuring is posing 
> issues for things like builds, IDE support, and the likes.
>
> I wonder if it wouldn't be sensible to do the repo restructuring now, 
> where the new repo is simply a consolidated version of the new one; no 
> need to update build scripts to take into account new paths. Then, 
> maybe in the next release (JDK 11), we could attack the source 
> restructuring problem. This way people will have more time to adjust 
> to the big changes that are coming.
>
> What do you think?
>

As a preface, I'm working to get the prototype of the consolidated 
repository externally visible and hope to have an update within the next 
few days.

The prototype did first combine the repositories such that all the 
relative paths were the same compared to the root. As I recall, this did 
require some nonzero updates to the build scripts. The second step was 
moving the module source directories to a consistent scheme. This 
required more makefile updates, but those updates have been made and the 
resulting build successfully compared to a pre-combined, 
pre-module-directory moved build, one of the recent JDK 9 promoted builds.

There is some cleanup work remaining to be done including updates for 
IDE support and scripts to massage patches across the consolidation 
boundary. I'm confident the essential remaining work can be completed 
within the next few weeks.

A consolidated repository without the source restructuring feels 
half-done and internally inconsistent to me.

Cheers,

-Joe