We have a workflow where any pull request from a feature branch to development branch (master) will have to be merged using "Squash" commit. We also have a separate production branch (release) from where our release builds are generated.

We have added a rule to not allow any modifications without a Pull Request on both master and release. When we have to make a new release, we would like to create a pull request from master to release branch. But if the merge strategy is "Squash", then those 2 branches would diverge.

So, we would like to make it a "Fast-forward only" merge if the source branch is master. Any merges from hotfix branches to release directly should still be "Squash" commits.

I know we can choose this option in each pull request individually, but it is error prone and would be more convenient to set it in the merge strategies setting to automatically choose the required type based on the source (and optionally target) branch.