When a new branch is created, some work needs to be done to specify that the previous branch is no longer equivalent to HEAD. The following instructions apply to the previous branch number:
Create a new zfs filesystem for sources:
zfs create a/snap/src-branch
Checkout a src tree in the new filesystem:
cvs -Rq -d /r/ncvs co -r RELENG-branch
Edit the master copy of Tools/portbuild/portbuild.conf.
For each arch, edit its copy of the above in /var/portbuild/arch/portbuild.conf.
Edit /var/portbuild/scripts/buildenv.
(Only necessary for old codebase): Add a link from /var/portbuild/scripts/dopackages to /var/portbuild/scripts/dopackages.branch.
Modify HEAD_BRANCH and NON_HEAD_BRANCHES in /var/portbuild/scripts/updatesnap.
(Only necessary for old codebase): Add the snap directory to /var/portbuild/scripts/zexpire.
(Only necessary for old codebase): In the /var/portbuild/errorlogs/ directory, create links for the webserver:
ln -s ../arch/branch/builds/latest/bak/errors arch-branch-full ln -s ../arch/branch/builds/latest/bak/logs arch-branch-full-logs ln -s ../arch/branch/builds/latest/errors arch-branch-latest ln -s ../arch/branch/builds/latest/logs arch-branch-latest-logs ln -s ../arch/branch/builds/latest/bak/packages arch-branch-packages-full ln -s ../arch/branch/builds/latest/packages arch-branch-packages-latest
Kick-start the build for the branch with
build create arch branch