Git branches are only "ahead" (or not) of a certain commit, not of another branch. Do you mean that you want to prevent the HEAD of your "main" branch from bei

Git branches are only "ahead" (or not) of a certain commit, not of another branch. Do you mean that you want to prevent the HEAD of your "main" branch from being a successor of the HEAD of the "develop" branch? Since it is always possible to put any commit you want in any branch, fixing incorrect situations with the worst case damage of keeping around mistaken commits that have been pushed to a shared repository, what would be the point?