DEVEL: Help with feature implementation

Hello everybody!

I want to implement a feature in git, and I'm looking for some help.

I wanted to add a history-simplification option to rev-list so that it doesn't simplify away any irrelevant commits if they have multiple relevant _children_, i.e. when they are the point where two relevant histories diverge.

Basically the effect I want for --show-forkpoints (named like --show-pulls): http://ix.io/2Ms6

But it seems there is no existing apparatus in the revision walker for deciding simplification on basis of *children*, am I correct? Admittedly my understanding of it is still a WIP, but I don't see anything that could help.

I was hoping that simply the flag CHILD_SHOWN could be checked, but it seems that's only set on boundary commits :(

This option would be pretty useful when used with some diffs, to see how much two forks have diverged. Currently if you use history simplification, the diffs for both divergent histories will be created against the last relevant commit instead of the last common ancestor, which creates pretty useless diffs with a lot of intersection between them.

Are there any viable alternative means to do this that I can explore?

Thanks!

FriendlyNeighborhoodShane