Proposal: manage all the source code in one repo

[luchsh]

Background

The CompoundVM JDK was built from source code of two repositories: modified jdk17u (aka this-repo), unmodified jdk8u. and the jdk8u source code was downloaded using wget at build time, see cvm.mk:150.

This approach has two drawbacks:

• the external dependency may be unstable, affected by network, permission, etc.;
• it would be hard to maintain changes in the downloaded package;

Proposal

This proposal tries to maintain all the source code in one repository (this one).

Design

• Put jdk8u/master to a standalone branch up/jdk8u/master and attached tags to it in this repo. which can be done via following commands

cd compoundVM/
git remote add jdk8u https://github.com/openjdk/jdk8u.git
git fetch jdk8u
git checkout -b up/jdk8u/master jdk8u/master
git push origin HEAD

Branch up/jdk8u/master has many shared history nodes with CompoundVM/master, thus no need to duplicate the whole git history tree.

• Modify cvm.mk to clone the up/jdk8u/master branch into directory $(JDK8U_SRCROOT) at build time.
• In the future, if some jdk8u changes has to be made, we may create a new branch out of this up/jdk8u/master and save those extra changes, all in one codebase.

Demo

I've created a demo in my fork repo, feel free to check out the code.