As you may have noticed there are some problems to implement a python generator with these *_foreach iterators of libgit2. I've opened an issue libgit2/libgit2#1384 for that. I'll let this issue open to collect some problematic _foreach functions. For the moment there are:

• git_references_foreach
• git_note_foreach

Diff seems to support as well some old fashioned way of iterating (not callback based). I'll look into that.