Ideally you want tooling that allows you to toggle between the diff between 2 and 3 and HEAD and 3, and to specify that 2 is the parent of 3. Some folks use "s

Ideally you want tooling that allows you to toggle between the diff between 2 and 3 and HEAD and 3, and to specify that 2 is the parent of 3. Some folks use "stacked diffs" or "stacked commits" to do this. Others use feature branches, or a patch series.