Development process#

BioSimSpace uses a main and devel development process, using feature branches for all code development.

  • main - this always contains the latest official release.

  • devel - this always contains the latest development release, which will become the next official release.

Code should be developed on a fork or in a feature branch called feature_{feature}. When your feature is ready, please submit a pull request against devel. This will trigger our continuos integration (CI) process, which will build BioSimSpace on a range of different platforms. All merge conflicts must be fixed in the branch and all tests must pass before the pull request can be merged into devel.( NOTE THAT ONLY AUTHORISED DEVELOPERS CAN ACCEPT THE PULL REQUEST.) Authorised developers will review the pull request as quickly as they can. They will be greatly helped if the feature is accompanied with tests, examples and/or tutorial instructions.


We encourage that new functionality in a pull request is documented, e.g. by adding to the tutorials or writing a detailed description for the website.

Assuming the CI completes successfully, then one of the release team will conduct a code review, with the code being merged into devel if it is approved.

Bug fixes or issue fixes are developed on fix branches, called fix_{number} (again in either the main repository or forks). If no issue thread exists for the bug that you are fixing, please open one to notify other users of the problem. This also allows us to correctly cross-reference and categorise pull requests. Once a fix is ready, please submit a pull request against devel. Assuming that the CI passes and the reviewers are happy, this will then be merged. The same approach should also be used for updates to documentation.

Once a fix has been approved and merged into devel one of the core developers will backport it to the previous major release, i.e. by applying the fix to the main branch. To do so, create a new fix branch based on main. If the files that were updated on devel as part of the fix don’t contain any other differences to those in main, i.e. they haven’t been updated during the merging of a new feature, then you can directly apply those to main. This can be done via:

git checkout devel file

where file is the path to the file that was changed. If multiple files in a directory were changed, then you can use:

git checkout devel directory

Note that the above approach will automatically stage the modified files. If you would prefer to be able to check the diff and make additional edits, then use git restore instead, e.g.:

git restore --source devel file

If the fix applied on devel was applied on top of a new feature, then you might be able to use git cherry-pick to apply the specific commits that relate only to the fix, e.g.

git cherry-pick commitSha

where commitSha is a commit reference. Use the --edit option if you want to change the commit message, and use --no-commit if you just want to apply the edits to the files on main, but not automatically make a new commit, e.g. if you want to check the results. (For more details, see here or here.)

Once the fix has been successfully applied, please raise a pull request against main for one of the development team to review. In cases where the updated files are identical to devel, it may not be necessary to ask for a review or run CI, since this would have been done when the fix was applied to devel. Once approved, the fix be merged into main.

Within a release cycle we will periodically create point releases on main, e.g. 2023.1.1. (The frequency will depend on the urgency of the fixes.)


The group of developers authorised to have access to the main BioSimSpace repository and to accept pull requests is not fixed, and will evolve over time. If you wish to join this group then please complete the tutorial and then demostrate your commitment by submitting good issues and pull requests from a personal fork of the repository. Please get in touch if you find this difficult, or follow this workshop and this workshop if you need to learn how to use Git, GitHub, feature branching, merging, pull requests etc.

Creating releases#

We use a calendar-based version numbering system, based on regular release cadence of several releases per year. Our aim is to make a major release every quarter (so four releases per year). Each release will be numbered sequentially, e.g. 2023.1.0 is the first release of 2023, 2023.2.0 is the second release. Our aim is that new functionality only appears in these “major” releases.

Major releases#

There are a number of stages to go through to create a major release:

  1. Make sure that all changes (features and fixes) that are required for the release have been merged into the devel branch, and the GitHub Action has run fully, building BioSimSpace on all supported platforms, running all the unit tests correctly, and building and uploading the conda packages to the dev channel on

  2. Create feature branches from devel to synchronise updates from external sandpits, e.g. here. (This may also be submitted as an external PR from the industrial partner.) Once ready, submit a pull request so that these updates can be tested and reviewed. (It might be the case the an external partner needs to run a larger set of internal tests against the changes.) When ready, this can be merged into devel by an authorised developer.

  3. The next task is to create a pull request to merge devel into main. At this point there might be conflicts to resolve due to previous backporting of fixes from devel into main. Since devel should now be the source of truth, an approach could be to perform the merge in the reverse fashion, taking everything from devel, after which the release branch has the exact same tree as devel, with all of the history and tags from main.

git checkout -b release devel
git merge -s ours main
  1. On the release branch, you will now need to update doc/source/changelog.rst with the changes since the last release. Start the entry with a title that (will) link to the changes on GitHub, e.g.…2023.1.0 links to the changes between the 2022.2.1 and 2023.1.0 releases. Follow a similar format for changes as already exist in this file. Try to link to pull requests and tutorials that describe new functionality if available.

  2. Typically Sire will be release at the same time, so you will need to update the version number in the requirements.txt file. Note that there are different versions of Sire for main and devel, so you will need to ensure that only the main version is uncommented and increment it to the latest version of Sire available on main.

  3. Now create a pull request for the release branch against main. Once the CI passes and it has been approved by an authorised developer it can be merged.

  4. An authorised developer will now create a tag for this release on main, e.g. using git tag -as {VERSION} -m "{VERSION} release", e.g. git tag -as 2023.1.0 -m "2023.1.0 release" would be the tag for the 2023.1.0 release. The tag can then be pushed to GitHub with git push origin tag, where tag is the new tag that you’ve created, e.g. 2023.1.0.

  5. Now we are finally ready to build the packages. This can be done by an authorised developer by triggering the workflow dispatch event for the Release Main workflow. At this point you will need to choose yes to upload packages to

  6. (*) GitHub Actions don’t currently build the ARM64/aarch64 packages. These have to be built and uploaded manually. On a MacOS/M1 or Linux/aarch64 computer you should create build environments for the Python versions that BioSimSpace should support. Activate this environment, and then checkout the main branch, run python actions/ and then run conda-build via the command conda mambabuild -c conda-forge -c openbiosim/label/main recipes/biosimspace. This will result in a conda package in the conda-bld directory in the root directory of your conda environment. You then need to upload these packages to, e.g. via the command anaconda --token {PASSWORD} upload --user openbiosim --label main {/path/to/biosimspace-packages} (modified as appropriate to include the anaconda password and the path to the built conda package).

  7. On GitHub, you can now create a release by using the Draft a New Release link. Choose the version number for your release from the tag you created earlier. The text should be simple, e.g. titled BioSimSpace {VERSION}, with the body This is the {VERSION} release of BioSimSpace., along with a link to the changelog for the release on the website (if a major release).

  8. Next you should build the docker images for this release. Do this by following the instructions in the containers repository. You should make sure to run the extra command listed there to tag the container with the version number you used earlier.

  9. Finally(!) you can now update the website. To do this, follow the instructions in the website repository.

  10. Bonus! Follow the instructions in the containers repository to build the notebook container image and instruct to update and use that image.

  11. Super-bonus! If you have time, please write a short news item piece that can be added to the openbiosim website to announce this new release.

(We are in the process of automating many of the above steps, so hope that this process will become much easier in the future.)

Point releases#

Between major releases it might be necessary to create point releases to fix bugs. Fixes will have been applied following the Development process and a release can be made by following steps 7 through 11 above. There is no need to create a changelog entry or update the website for a point release. (Unless fixes apply to the documentation itself.)

Development releases#

Following a major release, the next commit to devel will be given a new development tag based against the next major release number. For example, following the 2023.1.0 release, devel will be tagged with Following this, future merges into devel will trigger builds of development packages that will be pushed to our channel using the dev label. This allows users to pull and test features that will be available in the next major release on main.

Periodically an authorised user will update the development documentation on our website repository by running the workflow dispatch event against the devel branch.