If a change is likely to be disruptive or cause breakages in the program, the use of your own temporary branch is recommended. This private branch is a complete copy of one of the main development lines wherein you can make changes without disrupting the other developers. Although called a private branch every change is visible to all other developers and each commit will result in an automatic email to the relax-commits mailing list. Other developers are even able to check out your branch and make modifications to it. Private branches can also be used for testing ideas. If the idea does not work the branch can be deleted from the repository (in reality the branch will always exist between the revision numbers of its creation and deletion and can always be resurrected). For example to create a branch from the main development line, the `trunk', called molmol_macros whereby new Molmol macros are to be written, type
#Now check out the svn branch, which we will keep to perform certain svn commands.
cd ..
svn co svn+ssh://$RUSER@svn.gna.org/svn/relax/branches/$BRANCH ${BRANCH}_svn
</source>
For info about the commit template, see [[Format_commit_logs | Format commit logs]].
== Keeping the branch up to date using svnmerge.py ==
As you develop your branch, changes will be occurring simultaneously within the main line. These changes should be merged into your branch on a regular basis to avoid large incompatible changes from forming between the two branches. To simplify this process, the svnmerge.py script located at [http://www.orcaware.com/svn/wiki/Svnmerge.py http://www.orcaware.com/svn/wiki/Svnmerge.py] can be used. It is best to download the trunk version from that page, unless that version is non-functional.
#Once you have this script, the merging from the main line to your private branch must be initialised by typing, from within the checked out copy of your branch
svnmerge.py init
#This then needs to be committed using the automatically generated log
svn ci -F svnmerge-commit-message.txt
rm svnmerge-commit-message.txt
# See log
svn log -l 5
# To keep up to date, simply type
svnmerge.py avail
svnmerge.py merge
</source>
If conflicts have occurred please refer to the Subversion book at [http://svnbook.red-bean.com/ http://svnbook.red-bean.com/] for information on how to resolve the problem. Otherwise, or once fixed, the main line revisions merged into your branch can be committed using the automatically generated log file:
<source lang="bash">
svn ci -F svnmerge-commit-message.txt
</source>
=== BUG: svnmerge: no integration info available ===
If you receive a message like: '''svnmerge: no integration info available'''.<br>
Then you have probably run '''svnmerge.py''' before updating.
U test_suite/system_tests/scripts/relax_disp/cpmg_synthetic.py
property 'svnmerge-integrated' set on '.'
</source>
== Merging the branch back into the main line ==
Once you have completed the modifications desired for your branch, all changes which have occurred in the main line have been merged using svnmerge.py, and the changes have been approved for merging back into the main line - then your branch can be merged. First check out a copy of the main line,
<source lang="bash">
svn co svn+ssh://$RUSER@svn.gna.org/svn/relax/trunk relax-trunk
# or update a previously checked out version,
svn up
</source>
Then svnmerge.py can be utilised again. First initialise the merging process by typing, from within the checked out copy of the main line,