DevelopmentWorkflow

Contents

Development workflow

As of 2012-02-21, the git repository structure was modified to reflect the development workflow described here (see issue 96 for discussion).

Please check RepositoryStructure for details about the git repository structure.

master branch vs develop branch

The code repo is composed of two main branches:

• the master branch
• the develop branch

The master branch is used to store production-ready code. As a consequence, development code should never be committed to this branch. Ideally, only the release manager should commit code to this branch when a release is ready (See below).

The develop branch is where the magic happens! This is the branch used for development code. To avoid breaking things periodically, only working (and tested!) code should be committed to this branch. In other words, please consider this branch as an "integration branch" used to include your code into the next release.

Code integration into develop

As already mentioned, only "stabilized" code should be incorporated into the main development branch develop. When adding new features to MDAnalysis, developpers are asked to add the corresponding tests to the testsuite. Please check UnitTests for details.

Supporting branches

In addition to the master and develop branches, Three kinds of supporting branches may be used:

• feature branches
• release branches
• hotfix branches

feature branches

When you want to add an more-or-less experimental feature but still want other developers to be able to contribute (i.e. don't want to do everything locally), you may use a feature branch.

Rules for a feature branch:

• May branch from: develop
• Must be merged into: develop
• Naming convention: about anything except master, develop, release-*, hotfix-*

Typical workflow for feature development

• Create the branch from the develop branch:

git checkout -b myfeature develop

• Do some hacking... and commit
• Publish your branch (required only if you want to ease collaborative work):

git push -u origin myfeature

• More hacking and commits
• When your feature is ready to be implemented into the next release, merge back to the develop branch and publish it:

git checkout develop
git merge --no-ff myfeature
git push origin develop

Note: the --no-ff is used to prevent history loss

• Finally, you can delete your feature branch:

git branch -d myfeature

• ... And don't forget to delete the corresponding published branch (if you published it):

git push origin :myfeature

Release branches

release branches are used to prepare a new production release. They should be handled by the release manager only.

Rules for a release branch:

• May branch from: develop
• Must be merged into: master (and develop if needed)
• Naming convention: release-* where should be a version number

Typical workflow for preparating a release

• Create the branch from the develop branch:

git checkout -b release-0.7.6 develop

• Make sure the version number is right:

./maintainer/change_release.sh 0.7.6

• Check that everything is ready (documentation, unittests...)
• Commit the finalized state:

git commit -m "release 0.7.6 ready"

• Merge the branch into master and tag the release:

git checkout master
git merge --no-ff release-0.7.6
git tag -a release-0.7.6

• Merge the branch back into develop (actually this is not required if the only change was the version number):

git checkout develop
git merge --no-ff release-0.7.6
./maintainer/change_release.sh 0.7.7-devel
git commit -a -m "version number changed to 0.7.7-devel"

• Delete the release branch:

git branch -d release-0.7.6

the hotfix branches

hotfix branches are used to fix an issue found in a already released version. Like the release branches, they should be handled by the release manager only.

Rules for a feature branch:

• May branch from: master
• Must be merged into: master (and develop if needed)
• Naming convention: hotfix-* where should be a version number

Typical workflow for preparating a hotfix

• Create the branch from the master branch:

git checkout -b hotfix-0.7.6.1 master

• Make sure the version number is right:

./maintainer/change_release.sh 0.7.6.1

• Fix what has to be fixed.
• Commit the fixed state:

git commit -m "issue #123 fixed"

• Merge the branch into master and tag the release:

git checkout master
git merge --no-ff hotfix-0.7.6.1
git tag -a hotfix-0.7.6.1

• Merge the branch back into develop:

git checkout develop
git merge --no-ff hotfix-0.7.6.1

• Delete the hotfix branch:

git branch -d hotfix-0.7.6.1

Code development and debugging

In addition to the standard requirements, a developer should probably also install cython. In some cases it might be necessary to have SWIG as well.

Developers should be aware of how the setup.py script handles Cython code (see Issue 85):

• If no Cython, setup.py uses all the .c files that are included in the standard MDAnalysis distribution. If you changed any .pyx files then it will still use the old files!
• If Cython is installed, it is used to compile extension and .pyx source files are used instead of .c files.
• From there, .pyx files are converted to .c files if they are newer than the already present .c files or if the --force flag is set (e.g setup.py build --force).

By doing so, end users (or devs) should not trigger the .pyx to .c conversion since .c files delivered with source packages are always up to date. But devs who work on the .pyx files will automatically trigger the conversion since .c files will then be outdated. Using the --force flag with Cython installed will also trigger the conversion though.