missing support for parsing and using commit_graph files

[kevinhendricks]

From fighting with the lcas routines and getting commit times, I looked more into how actual git handles the inherently more unreliable commit times (due to cross repo mishandled time settings). Git uses generation numbers. A generation number is 1 plus the max of your parents generation numbers.p with the original first commit with no parents being 0. To prevent having to walk the full commit history dag, they now calculate these generations once and store it along with commit time and parent info into a commit_graph file (object) than has a very specific format file format that needs to be read in and written out just like an index file.

Having access to this information would make lcas lookup (and therefore merging) much easier.

Do you have any near term plans to add commit-graph file and lookup support to dulwich?

If not, would you be interested in having it contributed?

Thanks,

Kevin