git_diff_index_to_workdir fails to load untracked content when GIT_DIFF_REVERSE and GIT_DIFF_SHOW_UNTRACKED_CONTENT are set.

[arroz]

Reproduction steps

Assume the following code on a workdir with an untracked file with at least one line of content:

git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
git_diff *diff = NULL;
opts.flags |= GIT_DIFF_INCLUDE_UNTRACKED | GIT_DIFF_SHOW_UNTRACKED_CONTENT | GIT_DIFF_REVERSE;
git_diff_index_to_workdir(&diff, repo, NULL, &opts)

This diff will not properly load the content when inspected. Specifically, the following call will never get run diff_hunk_cb or diff_line_cb:

git_diff_foreach(diff, diff_file_cb, diff_binary_cb, diff_hunk_cb, diff_line_cb, &exp)

Expected behavior

The call above should call diff_hunk_cb once and diff_line_cb for each content line.

Actual behavior

The calls never happen because, internally, the content is never loaded.

Version of libgit2 (release number or SHA1)

2f20fe8869d7a1df7c9b7a9e2939c1a20533c6dc

Operating system(s) tested

macOS