Git tree show untracked files - c++

Question

I am trying to fix this issue:
https://github.com/gitahead/gitahead/issues/380
The problem is that the tree used in the model does not contain any untracked files and therefore the view has nothing to show. When I stage on file it is shown.
Is there a way to track in the tree also the untracked files?
I created a small test application to find the problem. When one file is staged, count is unequal to zero, otherwise it is always zero.
Testsetup
new git repository (TestRepository) with the following untracked files:
testfile.txt
testfolder/testfile2.txt
d
#include <git2.h>
#include <stdio.h>
int main() {
git_libgit2_init();
git_repository *repo = NULL;
int error = git_repository_open(&repo, "/TestRepository");
if (error < 0) {
const git_error *e = git_error_last();
printf("Error %d/%d: %s\n", error, e->klass, e->message);
exit(error);
}
git_tree *tree = nullptr;
git_index* idx = nullptr;
git_repository_index(&idx, repo);
git_oid id;
if (git_index_write_tree(&id, idx)) {
const git_error *e = git_error_last();
printf("Error %d/%d: %s\n", error, e->klass, e->message);
exit(error);
}
git_tree_lookup(&tree, repo, &id);
int count = git_tree_entrycount(tree);
printf("%d", count);
git_repository_free(repo);
printf("SUCCESS");
return 0;
}

Answer 1

If I understood correctly, what you're seeing is normal: as the file is untracked/new, the index has no knowledge of it, so if you ask the index, it has no "staged" changes to compare with, hence no diff.
If you want a diff for a yet-to-be tracked file, you'll have to provide it another way, usually by asking git_diff to do the work of comparing the worktree version with /dev/null, the empty blob, etc.
Since you're after a libgit2 solution, the way I'm trying to do that in GitX is via the git_status_list_new API, which gives a somewhat filesystem-independent way of generating both viewable diffs (staged & unstaged) on-the-fly, using git_patch_from_blobs/git_patch_from_blobs_and_buffer. In retrospect, maybe that should live in the library as git_status_entry_generate_patch or something…