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 * libgit2 "init" example - shows how to initialize a new repo
 * Written by the libgit2 contributors
 * To the extent possible under law, the author(s) have dedicated all copyright
 * and related and neighboring rights to this software to the public domain
 * worldwide. This software is distributed without any warranty.
 * You should have received a copy of the CC0 Public Domain Dedication along
 * with this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.

#include "common.h"

This is a sample program that is similar to "git init". See the documentation for that (try "git help init") to understand what this program is emulating.

This demonstrates using the libgit2 APIs to initialize a new repository.

This also contains a special additional option that regular "git init" does not support which is "--initial-commit" to make a first empty commit. That is demonstrated in the "createinitialcommit" helper function.

Forward declarations of helpers

struct init_opts {
  int no_options;
  int quiet;
  int bare;
  int initial_commit;
  uint32_t shared;
  const char *template;
  const char *gitdir;
  const char *dir;
static void create_initial_commit(git_repository *repo);
static void parse_opts(struct init_opts *o, int argc, char *argv[]);

int lg2_init(git_repository *repo, int argc, char *argv[])
  struct init_opts o = { 1, 0, 0, 0, GIT_REPOSITORY_INIT_SHARED_UMASK, 0, 0, 0 };

  parse_opts(&o, argc, argv);

  /* Initialize repository. */

  if (o.no_options) {

No options were specified, so let's demonstrate the default simple case of gitrepositoryinit() API usage...

    check_lg2(git_repository_init(&repo, o.dir, 0),
      "Could not initialize repository", NULL);
  else {

Some command line options were specified, so we'll use the extended init API to handle them

    git_repository_init_options initopts = GIT_REPOSITORY_INIT_OPTIONS_INIT;
    initopts.flags = GIT_REPOSITORY_INIT_MKPATH;

    if (o.bare)
      initopts.flags |= GIT_REPOSITORY_INIT_BARE;

    if (o.template) {
      initopts.template_path = o.template;

    if (o.gitdir) {

If you specified a separate git directory, then initialize the repository at that path and use the second path as the working directory of the repository (with a git-link file)

      initopts.workdir_path = o.dir;
      o.dir = o.gitdir;

    if (o.shared != 0)
      initopts.mode = o.shared;

    check_lg2(git_repository_init_ext(&repo, o.dir, &initopts),
        "Could not initialize repository", NULL);

Print a message to stdout like "git init" does.

  if (!o.quiet) {
    if (o.bare || o.gitdir)
      o.dir = git_repository_path(repo);
      o.dir = git_repository_workdir(repo);

    printf("Initialized empty Git repository in %s\n", o.dir);

As an extension to the basic "git init" command, this example gives the option to create an empty initial commit. This is mostly to demonstrate what it takes to do that, but also some people like to have that empty base commit in their repo.

  if (o.initial_commit) {
    printf("Created empty initial commit\n");


  return 0;

Unlike regular "git init", this example shows how to create an initial empty commit in the repository. This is the helper function that does that.

static void create_initial_commit(git_repository *repo)
  git_signature *sig;
  git_index *index;
  git_oid tree_id, commit_id;
  git_tree *tree;

First use the config to initialize a commit signature for the user.

  if (git_signature_default(&sig, repo) < 0)
    fatal("Unable to create a commit signature.",
          "Perhaps 'user.name' and 'user.email' are not set");

  /* Now let's create an empty tree for this commit */

  if (git_repository_index(&index, repo) < 0)
    fatal("Could not open repository index", NULL);

Outside of this example, you could call gitindexadd_bypath() here to put actual files into the index. For our purposes, we'll leave it empty for now.

  if (git_index_write_tree(&tree_id, index) < 0)
    fatal("Unable to write initial tree from index", NULL);


  if (git_tree_lookup(&tree, repo, &tree_id) < 0)
    fatal("Could not look up initial tree", NULL);

Ready to create the initial commit.

Normally creating a commit would involve looking up the current HEAD commit and making that be the parent of the initial commit, but here this is the first commit so there will be no parent.

  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);

Clean up so we don't leak memory.


static void usage(const char *error, const char *arg)
  fprintf(stderr, "error: %s '%s'\n", error, arg);
      "usage: init [-q | --quiet] [--bare] [--template=<dir>]\n"
      "            [--shared[=perms]] [--initial-commit]\n"
      "            [--separate-git-dir] <directory>\n");

Parse the tail of the --shared= argument.

static uint32_t parse_shared(const char *shared)
  if (!strcmp(shared, "false") || !strcmp(shared, "umask"))

  else if (!strcmp(shared, "true") || !strcmp(shared, "group"))

  else if (!strcmp(shared, "all") || !strcmp(shared, "world") ||
       !strcmp(shared, "everybody"))

  else if (shared[0] == '0') {
    long val;
    char *end = NULL;
    val = strtol(shared + 1, &end, 8);
    if (end == shared + 1 || *end != 0)
      usage("invalid octal value for --shared", shared);
    return (uint32_t)val;

    usage("unknown value for --shared", shared);

  return 0;

static void parse_opts(struct init_opts *o, int argc, char *argv[])
  struct args_info args = ARGS_INFO_INIT;
  const char *sharedarg;

Process arguments.

  for (args.pos = 1; args.pos < argc; ++args.pos) {
    char *a = argv[args.pos];

    if (a[0] == '-')
      o->no_options = 0;

    if (a[0] != '-') {
      if (o->dir != NULL)
        usage("extra argument", a);
      o->dir = a;
    else if (!strcmp(a, "-q") || !strcmp(a, "--quiet"))
      o->quiet = 1;
    else if (!strcmp(a, "--bare"))
      o->bare = 1;
    else if (!strcmp(a, "--shared"))
    else if (!strcmp(a, "--initial-commit"))
      o->initial_commit = 1;
    else if (match_str_arg(&sharedarg, &args, "--shared"))
      o->shared = parse_shared(sharedarg);
    else if (!match_str_arg(&o->template, &args, "--template") ||
             !match_str_arg(&o->gitdir, &args, "--separate-git-dir"))
      usage("unknown option", a);

  if (!o->dir)
    usage("must specify directory to init", "");