/*
* libgit2 "merge" example - shows how to perform merges
*
* 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"
#include <assert.h>
#ifdef _MSC_VER
#define snprintf sprintf_s
#endif
/** The following example demonstrates how to do merges with libgit2.
*
* It will merge whatever commit-ish you pass in into the current branch.
*
* Recognized options are :
* --no-commit: don't actually commit the merge.
*
*/
typedef struct {
const char **heads;
size_t heads_count;
git_annotated_commit **annotated;
size_t annotated_count;
int no_commit : 1;
} merge_options;
static void print_usage(void)
{
fprintf(stderr, "usage: merge [--no-commit] <commit...>\n");
exit(1);
}
static void merge_options_init(merge_options *opts)
{
opts->heads = NULL;
opts->heads_count = 0;
opts->annotated = NULL;
opts->annotated_count = 0;
}
static void opts_add_refish(merge_options *opts, const char *refish)
{
size_t sz;
assert(opts != NULL);
sz = ++opts->heads_count * sizeof(opts->heads[0]);
opts->heads = xrealloc(opts->heads, sz);
opts->heads[opts->heads_count - 1] = refish;
}
static void parse_options(const char **repo_path, merge_options *opts, int argc, char **argv)
{
struct args_info args = ARGS_INFO_INIT;
if (argc <= 1)
print_usage();
for (args.pos = 1; args.pos < argc; ++args.pos) {
const char *curr = argv[args.pos];
if (curr[0] != '-') {
opts_add_refish(opts, curr);
} else if (!strcmp(curr, "--no-commit")) {
opts->no_commit = 1;
} else if (match_str_arg(repo_path, &args, "--git-dir")) {
continue;
} else {
print_usage();
}
}
}
static int resolve_refish(git_annotated_commit **commit, git_repository *repo, const char *refish)
{
git_reference *ref;
int err = 0;
git_oid oid;
assert(commit != NULL);
err = git_reference_dwim(&ref, repo, refish);
if (err == GIT_OK) {
git_annotated_commit_from_ref(commit, repo, ref);
git_reference_free(ref);
return 0;
}
err = git_oid_fromstr(&oid, refish);
if (err == GIT_OK) {
err = git_annotated_commit_lookup(commit, repo, &oid);
}
return err;
}
static int resolve_heads(git_repository *repo, merge_options *opts)
{
git_annotated_commit **annotated = calloc(opts->heads_count, sizeof(git_annotated_commit *));
size_t annotated_count = 0, i;
int err = 0;
for (i = 0; i < opts->heads_count; i++) {
err = resolve_refish(&annotated[annotated_count++], repo, opts->heads[i]);
if (err != 0) {
fprintf(stderr, "failed to resolve refish %s: %s\n", opts->heads[i], giterr_last()->message);
annotated_count--;
continue;
}
}
if (annotated_count != opts->heads_count) {
fprintf(stderr, "unable to parse some refish\n");
free(annotated);
return -1;
}
opts->annotated = annotated;
opts->annotated_count = annotated_count;
return 0;
}
static int perform_fastforward(git_repository *repo, const git_oid *target_oid, int is_unborn)
{
git_checkout_options ff_checkout_options = GIT_CHECKOUT_OPTIONS_INIT;
git_reference *target_ref;
git_reference *new_target_ref;
git_object *target = NULL;
int err = 0;
if (is_unborn) {
const char *symbolic_ref;
git_reference *head_ref;
/* HEAD reference is unborn, lookup manually so we don't try to resolve it */
err = git_reference_lookup(&head_ref, repo, "HEAD");
if (err != 0) {
fprintf(stderr, "failed to lookup HEAD ref\n");
return -1;
}
/* Grab the reference HEAD should be pointing to */
symbolic_ref = git_reference_symbolic_target(head_ref);
/* Create our master reference on the target OID */
err = git_reference_create(&target_ref, repo, symbolic_ref, target_oid, 0, NULL);
if (err != 0) {
fprintf(stderr, "failed to create master reference\n");
return -1;
}
git_reference_free(head_ref);
} else {
/* HEAD exists, just lookup and resolve */
err = git_repository_head(&target_ref, repo);
if (err != 0) {
fprintf(stderr, "failed to get HEAD reference\n");
return -1;
}
}
/* Lookup the target object */
err = git_object_lookup(&target, repo, target_oid, GIT_OBJ_COMMIT);
if (err != 0) {
fprintf(stderr, "failed to lookup OID %s\n", git_oid_tostr_s(target_oid));
return -1;
}
/* Checkout the result so the workdir is in the expected state */
ff_checkout_options.checkout_strategy = GIT_CHECKOUT_SAFE;
err = git_checkout_tree(repo, target, &ff_checkout_options);
if (err != 0) {
fprintf(stderr, "failed to checkout HEAD reference\n");
return -1;
}
/* Move the target reference to the target OID */
err = git_reference_set_target(&new_target_ref, target_ref, target_oid, NULL);
if (err != 0) {
fprintf(stderr, "failed to move HEAD reference\n");
return -1;
}
git_reference_free(target_ref);
git_reference_free(new_target_ref);
git_object_free(target);
return 0;
}
static void output_conflicts(git_index *index)
{
git_index_conflict_iterator *conflicts;
const git_index_entry *ancestor;
const git_index_entry *our;
const git_index_entry *their;
int err = 0;
check_lg2(git_index_conflict_iterator_new(&conflicts, index), "failed to create conflict iterator", NULL);
while ((err = git_index_conflict_next(&ancestor, &our, &their, conflicts)) == 0) {
fprintf(stderr, "conflict: a:%s o:%s t:%s\n",
ancestor ? ancestor->path : "NULL",
our->path ? our->path : "NULL",
their->path ? their->path : "NULL");
}
if (err != GIT_ITEROVER) {
fprintf(stderr, "error iterating conflicts\n");
}
git_index_conflict_iterator_free(conflicts);
}
static int create_merge_commit(git_repository *repo, git_index *index, merge_options *opts)
{
git_oid tree_oid, commit_oid;
git_tree *tree;
git_signature *sign;
git_reference *merge_ref = NULL;
git_annotated_commit *merge_commit;
git_reference *head_ref;
git_commit **parents = calloc(opts->annotated_count + 1, sizeof(git_commit *));
const char *msg_target = NULL;
size_t msglen = 0;
char *msg;
size_t i;
int err;
/* Grab our needed references */
check_lg2(git_repository_head(&head_ref, repo), "failed to get repo HEAD", NULL);
if (resolve_refish(&merge_commit, repo, opts->heads[0])) {
fprintf(stderr, "failed to resolve refish %s", opts->heads[0]);
return -1;
}
/* Maybe that's a ref, so DWIM it */
err = git_reference_dwim(&merge_ref, repo, opts->heads[0]);
check_lg2(err, "failed to DWIM reference", giterr_last()->message);
/* Grab a signature */
check_lg2(git_signature_now(&sign, "Me", "me@example.com"), "failed to create signature", NULL);
#define MERGE_COMMIT_MSG "Merge %s '%s'"
/* Prepare a standard merge commit message */
if (merge_ref != NULL) {
check_lg2(git_branch_name(&msg_target, merge_ref), "failed to get branch name of merged ref", NULL);
} else {
msg_target = git_oid_tostr_s(git_annotated_commit_id(merge_commit));
}
msglen = snprintf(NULL, 0, MERGE_COMMIT_MSG, (merge_ref ? "branch" : "commit"), msg_target);
if (msglen > 0) msglen++;
msg = malloc(msglen);
err = snprintf(msg, msglen, MERGE_COMMIT_MSG, (merge_ref ? "branch" : "commit"), msg_target);
/* This is only to silence the compiler */
if (err < 0) goto cleanup;
/* Setup our parent commits */
err = git_reference_peel((git_object **)&parents[0], head_ref, GIT_OBJ_COMMIT);
check_lg2(err, "failed to peel head reference", NULL);
for (i = 0; i < opts->annotated_count; i++) {
git_commit_lookup(&parents[i + 1], repo, git_annotated_commit_id(opts->annotated[i]));
}
/* Prepare our commit tree */
check_lg2(git_index_write_tree(&tree_oid, index), "failed to write merged tree", NULL);
check_lg2(git_tree_lookup(&tree, repo, &tree_oid), "failed to lookup tree", NULL);
/* Commit time ! */
err = git_commit_create(&commit_oid,
repo, git_reference_name(head_ref),
sign, sign,
NULL, msg,
tree,
opts->annotated_count + 1, (const git_commit **)parents);
check_lg2(err, "failed to create commit", NULL);
/* We're done merging, cleanup the repository state */
git_repository_state_cleanup(repo);
cleanup:
free(parents);
return err;
}
int main(int argc, char **argv)
{
git_repository *repo = NULL;
merge_options opts;
git_index *index;
git_repository_state_t state;
git_merge_analysis_t analysis;
git_merge_preference_t preference;
const char *path = ".";
int err = 0;
merge_options_init(&opts);
parse_options(&path, &opts, argc, argv);
git_libgit2_init();
check_lg2(git_repository_open_ext(&repo, path, 0, NULL),
"Could not open repository", NULL);
state = git_repository_state(repo);
if (state != GIT_REPOSITORY_STATE_NONE) {
fprintf(stderr, "repository is in unexpected state %d\n", state);
goto cleanup;
}
err = resolve_heads(repo, &opts);
if (err != 0)
goto cleanup;
err = git_merge_analysis(&analysis, &preference,
repo,
(const git_annotated_commit **)opts.annotated,
opts.annotated_count);
check_lg2(err, "merge analysis failed", NULL);
if (analysis & GIT_MERGE_ANALYSIS_UP_TO_DATE) {
printf("Already up-to-date\n");
return 0;
} else if (analysis & GIT_MERGE_ANALYSIS_UNBORN ||
(analysis & GIT_MERGE_ANALYSIS_FASTFORWARD &&
!(preference & GIT_MERGE_PREFERENCE_NO_FASTFORWARD))) {
const git_oid *target_oid;
if (analysis & GIT_MERGE_ANALYSIS_UNBORN) {
printf("Unborn\n");
} else {
printf("Fast-forward\n");
}
/* Since this is a fast-forward, there can be only one merge head */
target_oid = git_annotated_commit_id(opts.annotated[0]);
assert(opts.annotated_count == 1);
return perform_fastforward(repo, target_oid, (analysis & GIT_MERGE_ANALYSIS_UNBORN));
} else if (analysis & GIT_MERGE_ANALYSIS_NORMAL) {
git_merge_options merge_opts = GIT_MERGE_OPTIONS_INIT;
git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
merge_opts.flags = 0;
merge_opts.file_flags = GIT_MERGE_FILE_STYLE_DIFF3;
checkout_opts.checkout_strategy = GIT_CHECKOUT_FORCE|GIT_CHECKOUT_ALLOW_CONFLICTS;
if (preference & GIT_MERGE_PREFERENCE_FASTFORWARD_ONLY) {
printf("Fast-forward is preferred, but only a merge is possible\n");
return -1;
}
err = git_merge(repo,
(const git_annotated_commit **)opts.annotated, opts.annotated_count,
&merge_opts, &checkout_opts);
check_lg2(err, "merge failed", NULL);
}
/* If we get here, we actually performed the merge above */
check_lg2(git_repository_index(&index, repo), "failed to get repository index", NULL);
if (git_index_has_conflicts(index)) {
/* Handle conflicts */
output_conflicts(index);
} else if (!opts.no_commit) {
create_merge_commit(repo, index, &opts);
printf("Merge made\n");
}
cleanup:
free(opts.heads);
free(opts.annotated);
git_repository_free(repo);
git_libgit2_shutdown();
return 0;
}
