Using libgit2, how can an empty initial commit be created?

Question

Previously I had asked how one could create an empty commit in libgit2 . That question was fully answered, however I wasn't clear enough when I initially asked it.

Using libgit2, how can one create an empty initial commit? The answer to my previous question relies on having the parent commit object, which I don't know how to obtain for an empty repository. Perhaps something could be done using the empty tree object (whose hash can be generated with git hash-object -t tree /dev/null )?

Answer 1

While writing my question, I came across an example on the libgit2 reference , which had exactly what I needed.

 static void create_initial_commit(git_repository *repo) { git_signature *sig; git_index *index; git_oid tree_id, commit_id; git_tree *tree; if (git_signature_default(&sig, repo) < 0) fatal("Unable to create a commit signature.", "Perhaps 'user.name' and 'user.email' are not set"); if (git_repository_index(&index, repo) < 0) fatal("Could not open repository index", NULL); if (git_index_write_tree(&tree_id, index) < 0) fatal("Unable to write initial tree from index", NULL); git_index_free(index); if (git_tree_lookup(&tree, repo, &tree_id) < 0) fatal("Could not look up initial tree", NULL); if (git_commit_create_v(&commit_id, repo, "HEAD", sig, sig, NULL, "Initial commit", tree, 0) < 0) fatal("Could not create the initial commit", NULL); git_tree_free(tree); git_signature_free(sig); }

This function creates an empty initial commit. It reads the index from the empty repository, then uses that to obtains the ID of the empty tree ( 4b825dc642cb6eb9a060e54bf8d69288fbee4904 ), then uses that to obtain the empty tree, and finally creates the empty initial commit using that tree.