These are some issues I found while playing around with the new parser for docurium.
Use an unsigned int for the version and add a helper macro so the code is simplified (and so the error message is a common string).
Since git_diff_init_options was introduced, remove this old fn.
When diff is scanning the working directory, if it finds a file where it is not sure if the index entry matches the working dir, it will recalculate the OID (which is pretty expensive). This adds a new flag to diff so that if the OID calculation finds that the file actually has not changed (i.e. just the modified time was altered or such), then it will refresh the stat cache in the index so that future calls to diff will not have to check the oid again.
patch: emit deflated binary patches (optionally)
This takes the `--stat` and related example options in the example diff.c program and converts them to use the `git_diff_get_stats` API which nicely formats stats for you. I went to add bar-graph scaling to the stats formatter and noticed that the `git_diff_stats` structure was holding on to all of the `git_patch` objects. Unfortunately, each of these objects keeps the full text of the diff in memory, so this is very expensive. I ended up modifying `git_diff_stats` to keep just the data that it needs to keep and allowed it to release the patches. Then, I added width scaling to the output on top of that. In making the diff example program match 'git diff' output, I ended up removing an newline from the sumamry output which I then had to compensate for in the email formatting to match the expectations. Lastly, I went through and refactored the tests to use a couple of helper functions and reduce the overall amount of code there.
I was playing with "git diff-index" and wanted to be able to emulate that behavior a little more closely with the diff example. Also, I wanted to play with running `git_diff_tree_to_workdir` directly even though core Git doesn't exactly have the equivalent, so I added a command line option for that and tweaked some other things in the example code. This changes a minor output thing in that the "raw" print helper function will no longer add ellipses (...) if the OID is not actually abbreviated.