Best practices in modelling a tax and benefits system country package

Nuggets of knowledge around how the OpenFisca community solves its problems.

Which branching strategy is the most appropriate?

I would recommend to do trunk-based development, and always merge against master. Long-lived branches make it easier to deliver a specific feature, but since the value of OpenFisca lies in ensuring each tiny improvement is made available for reuse across all formulas, it is very often:

1. Conflict-prone to merge two diverging branches.
2. Frustrating to not be able to reuse that definition you just added in another branch.
3. Impossible to keep up with upstream updates when you get many other collaborators working on the model. The administrative costs of upgrading to keep a branch alive for more than a week are very high in France, for example.

— @MattiSG