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builtin-merge.c
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builtin-merge.c
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/*
* Builtin "git merge"
*
* Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
*
* Based on git-merge.sh by Junio C Hamano.
*/
#include "cache.h"
#include "parse-options.h"
#include "builtin.h"
#include "run-command.h"
#include "diff.h"
#include "refs.h"
#include "commit.h"
#include "diffcore.h"
#include "revision.h"
#include "unpack-trees.h"
#include "cache-tree.h"
#include "dir.h"
#include "utf8.h"
#include "log-tree.h"
#include "color.h"
#include "rerere.h"
#include "help.h"
#include "merge-recursive.h"
#define DEFAULT_TWOHEAD (1<<0)
#define DEFAULT_OCTOPUS (1<<1)
#define NO_FAST_FORWARD (1<<2)
#define NO_TRIVIAL (1<<3)
struct strategy {
const char *name;
unsigned attr;
};
static const char * const builtin_merge_usage[] = {
"git merge [options] <remote>...",
"git merge [options] <msg> HEAD <remote>",
NULL
};
static int show_diffstat = 1, option_log, squash;
static int option_commit = 1, allow_fast_forward = 1;
static int allow_trivial = 1, have_message;
static struct strbuf merge_msg;
static struct commit_list *remoteheads;
static unsigned char head[20], stash[20];
static struct strategy **use_strategies;
static size_t use_strategies_nr, use_strategies_alloc;
static const char *branch;
static int verbosity;
static struct strategy all_strategy[] = {
{ "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
{ "octopus", DEFAULT_OCTOPUS },
{ "resolve", 0 },
{ "ours", NO_FAST_FORWARD | NO_TRIVIAL },
{ "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
};
static const char *pull_twohead, *pull_octopus;
static int option_parse_message(const struct option *opt,
const char *arg, int unset)
{
struct strbuf *buf = opt->value;
if (unset)
strbuf_setlen(buf, 0);
else if (arg) {
strbuf_addf(buf, "%s\n\n", arg);
have_message = 1;
} else
return error("switch `m' requires a value");
return 0;
}
static struct strategy *get_strategy(const char *name)
{
int i;
struct strategy *ret;
static struct cmdnames main_cmds, other_cmds;
static int loaded;
if (!name)
return NULL;
for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
if (!strcmp(name, all_strategy[i].name))
return &all_strategy[i];
if (!loaded) {
struct cmdnames not_strategies;
loaded = 1;
memset(¬_strategies, 0, sizeof(struct cmdnames));
load_command_list("git-merge-", &main_cmds, &other_cmds);
for (i = 0; i < main_cmds.cnt; i++) {
int j, found = 0;
struct cmdname *ent = main_cmds.names[i];
for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
if (!strncmp(ent->name, all_strategy[j].name, ent->len)
&& !all_strategy[j].name[ent->len])
found = 1;
if (!found)
add_cmdname(¬_strategies, ent->name, ent->len);
exclude_cmds(&main_cmds, ¬_strategies);
}
}
if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
fprintf(stderr, "Available strategies are:");
for (i = 0; i < main_cmds.cnt; i++)
fprintf(stderr, " %s", main_cmds.names[i]->name);
fprintf(stderr, ".\n");
if (other_cmds.cnt) {
fprintf(stderr, "Available custom strategies are:");
for (i = 0; i < other_cmds.cnt; i++)
fprintf(stderr, " %s", other_cmds.names[i]->name);
fprintf(stderr, ".\n");
}
exit(1);
}
ret = xcalloc(1, sizeof(struct strategy));
ret->name = xstrdup(name);
return ret;
}
static void append_strategy(struct strategy *s)
{
ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
use_strategies[use_strategies_nr++] = s;
}
static int option_parse_strategy(const struct option *opt,
const char *name, int unset)
{
if (unset)
return 0;
append_strategy(get_strategy(name));
return 0;
}
static int option_parse_n(const struct option *opt,
const char *arg, int unset)
{
show_diffstat = unset;
return 0;
}
static struct option builtin_merge_options[] = {
{ OPTION_CALLBACK, 'n', NULL, NULL, NULL,
"do not show a diffstat at the end of the merge",
PARSE_OPT_NOARG, option_parse_n },
OPT_BOOLEAN(0, "stat", &show_diffstat,
"show a diffstat at the end of the merge"),
OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
OPT_BOOLEAN(0, "log", &option_log,
"add list of one-line log to merge commit message"),
OPT_BOOLEAN(0, "squash", &squash,
"create a single commit instead of doing a merge"),
OPT_BOOLEAN(0, "commit", &option_commit,
"perform a commit if the merge succeeds (default)"),
OPT_BOOLEAN(0, "ff", &allow_fast_forward,
"allow fast forward (default)"),
OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
"merge strategy to use", option_parse_strategy),
OPT_CALLBACK('m', "message", &merge_msg, "message",
"message to be used for the merge commit (if any)",
option_parse_message),
OPT__VERBOSITY(&verbosity),
OPT_END()
};
/* Cleans up metadata that is uninteresting after a succeeded merge. */
static void drop_save(void)
{
unlink(git_path("MERGE_HEAD"));
unlink(git_path("MERGE_MSG"));
unlink(git_path("MERGE_MODE"));
}
static void save_state(void)
{
int len;
struct child_process cp;
struct strbuf buffer = STRBUF_INIT;
const char *argv[] = {"stash", "create", NULL};
memset(&cp, 0, sizeof(cp));
cp.argv = argv;
cp.out = -1;
cp.git_cmd = 1;
if (start_command(&cp))
die("could not run stash.");
len = strbuf_read(&buffer, cp.out, 1024);
close(cp.out);
if (finish_command(&cp) || len < 0)
die("stash failed");
else if (!len)
return;
strbuf_setlen(&buffer, buffer.len-1);
if (get_sha1(buffer.buf, stash))
die("not a valid object: %s", buffer.buf);
}
static void reset_hard(unsigned const char *sha1, int verbose)
{
int i = 0;
const char *args[6];
args[i++] = "read-tree";
if (verbose)
args[i++] = "-v";
args[i++] = "--reset";
args[i++] = "-u";
args[i++] = sha1_to_hex(sha1);
args[i] = NULL;
if (run_command_v_opt(args, RUN_GIT_CMD))
die("read-tree failed");
}
static void restore_state(void)
{
struct strbuf sb = STRBUF_INIT;
const char *args[] = { "stash", "apply", NULL, NULL };
if (is_null_sha1(stash))
return;
reset_hard(head, 1);
args[2] = sha1_to_hex(stash);
/*
* It is OK to ignore error here, for example when there was
* nothing to restore.
*/
run_command_v_opt(args, RUN_GIT_CMD);
strbuf_release(&sb);
refresh_cache(REFRESH_QUIET);
}
/* This is called when no merge was necessary. */
static void finish_up_to_date(const char *msg)
{
if (verbosity >= 0)
printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
drop_save();
}
static void squash_message(void)
{
struct rev_info rev;
struct commit *commit;
struct strbuf out = STRBUF_INIT;
struct commit_list *j;
int fd;
printf("Squash commit -- not updating HEAD\n");
fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
if (fd < 0)
die("Could not write to %s", git_path("SQUASH_MSG"));
init_revisions(&rev, NULL);
rev.ignore_merges = 1;
rev.commit_format = CMIT_FMT_MEDIUM;
commit = lookup_commit(head);
commit->object.flags |= UNINTERESTING;
add_pending_object(&rev, &commit->object, NULL);
for (j = remoteheads; j; j = j->next)
add_pending_object(&rev, &j->item->object, NULL);
setup_revisions(0, NULL, &rev, NULL);
if (prepare_revision_walk(&rev))
die("revision walk setup failed");
strbuf_addstr(&out, "Squashed commit of the following:\n");
while ((commit = get_revision(&rev)) != NULL) {
strbuf_addch(&out, '\n');
strbuf_addf(&out, "commit %s\n",
sha1_to_hex(commit->object.sha1));
pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
NULL, NULL, rev.date_mode, 0);
}
if (write(fd, out.buf, out.len) < 0)
die("Writing SQUASH_MSG: %s", strerror(errno));
if (close(fd))
die("Finishing SQUASH_MSG: %s", strerror(errno));
strbuf_release(&out);
}
static void finish(const unsigned char *new_head, const char *msg)
{
struct strbuf reflog_message = STRBUF_INIT;
if (!msg)
strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
else {
if (verbosity >= 0)
printf("%s\n", msg);
strbuf_addf(&reflog_message, "%s: %s",
getenv("GIT_REFLOG_ACTION"), msg);
}
if (squash) {
squash_message();
} else {
if (verbosity >= 0 && !merge_msg.len)
printf("No merge message -- not updating HEAD\n");
else {
const char *argv_gc_auto[] = { "gc", "--auto", NULL };
update_ref(reflog_message.buf, "HEAD",
new_head, head, 0,
DIE_ON_ERR);
/*
* We ignore errors in 'gc --auto', since the
* user should see them.
*/
run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
}
}
if (new_head && show_diffstat) {
struct diff_options opts;
diff_setup(&opts);
opts.output_format |=
DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
opts.detect_rename = DIFF_DETECT_RENAME;
if (diff_use_color_default > 0)
DIFF_OPT_SET(&opts, COLOR_DIFF);
if (diff_setup_done(&opts) < 0)
die("diff_setup_done failed");
diff_tree_sha1(head, new_head, "", &opts);
diffcore_std(&opts);
diff_flush(&opts);
}
/* Run a post-merge hook */
run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
strbuf_release(&reflog_message);
}
/* Get the name for the merge commit's message. */
static void merge_name(const char *remote, struct strbuf *msg)
{
struct object *remote_head;
unsigned char branch_head[20], buf_sha[20];
struct strbuf buf = STRBUF_INIT;
struct strbuf bname = STRBUF_INIT;
const char *ptr;
int len, early;
len = strlen(remote);
if (interpret_nth_last_branch(remote, &bname) == len)
remote = bname.buf;
memset(branch_head, 0, sizeof(branch_head));
remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
if (!remote_head)
die("'%s' does not point to a commit", remote);
strbuf_addstr(&buf, "refs/heads/");
strbuf_addstr(&buf, remote);
resolve_ref(buf.buf, branch_head, 0, 0);
if (!hashcmp(remote_head->sha1, branch_head)) {
strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
sha1_to_hex(branch_head), remote);
goto cleanup;
}
/* See if remote matches <name>^^^.. or <name>~<number> */
for (len = 0, ptr = remote + strlen(remote);
remote < ptr && ptr[-1] == '^';
ptr--)
len++;
if (len)
early = 1;
else {
early = 0;
ptr = strrchr(remote, '~');
if (ptr) {
int seen_nonzero = 0;
len++; /* count ~ */
while (*++ptr && isdigit(*ptr)) {
seen_nonzero |= (*ptr != '0');
len++;
}
if (*ptr)
len = 0; /* not ...~<number> */
else if (seen_nonzero)
early = 1;
else if (len == 1)
early = 1; /* "name~" is "name~1"! */
}
}
if (len) {
struct strbuf truname = STRBUF_INIT;
strbuf_addstr(&truname, "refs/heads/");
strbuf_addstr(&truname, remote);
strbuf_setlen(&truname, truname.len - len);
if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
strbuf_addf(msg,
"%s\t\tbranch '%s'%s of .\n",
sha1_to_hex(remote_head->sha1),
truname.buf + 11,
(early ? " (early part)" : ""));
strbuf_release(&truname);
goto cleanup;
}
}
if (!strcmp(remote, "FETCH_HEAD") &&
!access(git_path("FETCH_HEAD"), R_OK)) {
FILE *fp;
struct strbuf line = STRBUF_INIT;
char *ptr;
fp = fopen(git_path("FETCH_HEAD"), "r");
if (!fp)
die("could not open %s for reading: %s",
git_path("FETCH_HEAD"), strerror(errno));
strbuf_getline(&line, fp, '\n');
fclose(fp);
ptr = strstr(line.buf, "\tnot-for-merge\t");
if (ptr)
strbuf_remove(&line, ptr-line.buf+1, 13);
strbuf_addbuf(msg, &line);
strbuf_release(&line);
goto cleanup;
}
strbuf_addf(msg, "%s\t\tcommit '%s'\n",
sha1_to_hex(remote_head->sha1), remote);
cleanup:
strbuf_release(&buf);
strbuf_release(&bname);
}
static int git_merge_config(const char *k, const char *v, void *cb)
{
if (branch && !prefixcmp(k, "branch.") &&
!prefixcmp(k + 7, branch) &&
!strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
const char **argv;
int argc;
char *buf;
buf = xstrdup(v);
argc = split_cmdline(buf, &argv);
if (argc < 0)
die("Bad branch.%s.mergeoptions string", branch);
argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
argc++;
parse_options(argc, argv, builtin_merge_options,
builtin_merge_usage, 0);
free(buf);
}
if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
show_diffstat = git_config_bool(k, v);
else if (!strcmp(k, "pull.twohead"))
return git_config_string(&pull_twohead, k, v);
else if (!strcmp(k, "pull.octopus"))
return git_config_string(&pull_octopus, k, v);
else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
option_log = git_config_bool(k, v);
return git_diff_ui_config(k, v, cb);
}
static int read_tree_trivial(unsigned char *common, unsigned char *head,
unsigned char *one)
{
int i, nr_trees = 0;
struct tree *trees[MAX_UNPACK_TREES];
struct tree_desc t[MAX_UNPACK_TREES];
struct unpack_trees_options opts;
memset(&opts, 0, sizeof(opts));
opts.head_idx = 2;
opts.src_index = &the_index;
opts.dst_index = &the_index;
opts.update = 1;
opts.verbose_update = 1;
opts.trivial_merges_only = 1;
opts.merge = 1;
trees[nr_trees] = parse_tree_indirect(common);
if (!trees[nr_trees++])
return -1;
trees[nr_trees] = parse_tree_indirect(head);
if (!trees[nr_trees++])
return -1;
trees[nr_trees] = parse_tree_indirect(one);
if (!trees[nr_trees++])
return -1;
opts.fn = threeway_merge;
cache_tree_free(&active_cache_tree);
for (i = 0; i < nr_trees; i++) {
parse_tree(trees[i]);
init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
}
if (unpack_trees(nr_trees, t, &opts))
return -1;
return 0;
}
static void write_tree_trivial(unsigned char *sha1)
{
if (write_cache_as_tree(sha1, 0, NULL))
die("git write-tree failed to write a tree");
}
static int try_merge_strategy(const char *strategy, struct commit_list *common,
const char *head_arg)
{
const char **args;
int i = 0, ret;
struct commit_list *j;
struct strbuf buf = STRBUF_INIT;
int index_fd;
struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
index_fd = hold_locked_index(lock, 1);
refresh_cache(REFRESH_QUIET);
if (active_cache_changed &&
(write_cache(index_fd, active_cache, active_nr) ||
commit_locked_index(lock)))
return error("Unable to write index.");
rollback_lock_file(lock);
if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
int clean;
struct commit *result;
struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
int index_fd;
struct commit_list *reversed = NULL;
struct merge_options o;
if (remoteheads->next) {
error("Not handling anything other than two heads merge.");
return 2;
}
init_merge_options(&o);
if (!strcmp(strategy, "subtree"))
o.subtree_merge = 1;
o.branch1 = head_arg;
o.branch2 = remoteheads->item->util;
for (j = common; j; j = j->next)
commit_list_insert(j->item, &reversed);
index_fd = hold_locked_index(lock, 1);
clean = merge_recursive(&o, lookup_commit(head),
remoteheads->item, reversed, &result);
if (active_cache_changed &&
(write_cache(index_fd, active_cache, active_nr) ||
commit_locked_index(lock)))
die ("unable to write %s", get_index_file());
rollback_lock_file(lock);
return clean ? 0 : 1;
} else {
args = xmalloc((4 + commit_list_count(common) +
commit_list_count(remoteheads)) * sizeof(char *));
strbuf_addf(&buf, "merge-%s", strategy);
args[i++] = buf.buf;
for (j = common; j; j = j->next)
args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
args[i++] = "--";
args[i++] = head_arg;
for (j = remoteheads; j; j = j->next)
args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
args[i] = NULL;
ret = run_command_v_opt(args, RUN_GIT_CMD);
strbuf_release(&buf);
i = 1;
for (j = common; j; j = j->next)
free((void *)args[i++]);
i += 2;
for (j = remoteheads; j; j = j->next)
free((void *)args[i++]);
free(args);
discard_cache();
if (read_cache() < 0)
die("failed to read the cache");
return -ret;
}
}
static void count_diff_files(struct diff_queue_struct *q,
struct diff_options *opt, void *data)
{
int *count = data;
(*count) += q->nr;
}
static int count_unmerged_entries(void)
{
const struct index_state *state = &the_index;
int i, ret = 0;
for (i = 0; i < state->cache_nr; i++)
if (ce_stage(state->cache[i]))
ret++;
return ret;
}
static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
{
struct tree *trees[MAX_UNPACK_TREES];
struct unpack_trees_options opts;
struct tree_desc t[MAX_UNPACK_TREES];
int i, fd, nr_trees = 0;
struct dir_struct dir;
struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
refresh_cache(REFRESH_QUIET);
fd = hold_locked_index(lock_file, 1);
memset(&trees, 0, sizeof(trees));
memset(&opts, 0, sizeof(opts));
memset(&t, 0, sizeof(t));
memset(&dir, 0, sizeof(dir));
dir.show_ignored = 1;
dir.exclude_per_dir = ".gitignore";
opts.dir = &dir;
opts.head_idx = 1;
opts.src_index = &the_index;
opts.dst_index = &the_index;
opts.update = 1;
opts.verbose_update = 1;
opts.merge = 1;
opts.fn = twoway_merge;
trees[nr_trees] = parse_tree_indirect(head);
if (!trees[nr_trees++])
return -1;
trees[nr_trees] = parse_tree_indirect(remote);
if (!trees[nr_trees++])
return -1;
for (i = 0; i < nr_trees; i++) {
parse_tree(trees[i]);
init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
}
if (unpack_trees(nr_trees, t, &opts))
return -1;
if (write_cache(fd, active_cache, active_nr) ||
commit_locked_index(lock_file))
die("unable to write new index file");
return 0;
}
static void split_merge_strategies(const char *string, struct strategy **list,
int *nr, int *alloc)
{
char *p, *q, *buf;
if (!string)
return;
buf = xstrdup(string);
q = buf;
for (;;) {
p = strchr(q, ' ');
if (!p) {
ALLOC_GROW(*list, *nr + 1, *alloc);
(*list)[(*nr)++].name = xstrdup(q);
free(buf);
return;
} else {
*p = '\0';
ALLOC_GROW(*list, *nr + 1, *alloc);
(*list)[(*nr)++].name = xstrdup(q);
q = ++p;
}
}
}
static void add_strategies(const char *string, unsigned attr)
{
struct strategy *list = NULL;
int list_alloc = 0, list_nr = 0, i;
memset(&list, 0, sizeof(list));
split_merge_strategies(string, &list, &list_nr, &list_alloc);
if (list) {
for (i = 0; i < list_nr; i++)
append_strategy(get_strategy(list[i].name));
return;
}
for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
if (all_strategy[i].attr & attr)
append_strategy(&all_strategy[i]);
}
static int merge_trivial(void)
{
unsigned char result_tree[20], result_commit[20];
struct commit_list *parent = xmalloc(sizeof(*parent));
write_tree_trivial(result_tree);
printf("Wonderful.\n");
parent->item = lookup_commit(head);
parent->next = xmalloc(sizeof(*parent->next));
parent->next->item = remoteheads->item;
parent->next->next = NULL;
commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
finish(result_commit, "In-index merge");
drop_save();
return 0;
}
static int finish_automerge(struct commit_list *common,
unsigned char *result_tree,
const char *wt_strategy)
{
struct commit_list *parents = NULL, *j;
struct strbuf buf = STRBUF_INIT;
unsigned char result_commit[20];
free_commit_list(common);
if (allow_fast_forward) {
parents = remoteheads;
commit_list_insert(lookup_commit(head), &parents);
parents = reduce_heads(parents);
} else {
struct commit_list **pptr = &parents;
pptr = &commit_list_insert(lookup_commit(head),
pptr)->next;
for (j = remoteheads; j; j = j->next)
pptr = &commit_list_insert(j->item, pptr)->next;
}
free_commit_list(remoteheads);
strbuf_addch(&merge_msg, '\n');
commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
finish(result_commit, buf.buf);
strbuf_release(&buf);
drop_save();
return 0;
}
static int suggest_conflicts(void)
{
FILE *fp;
int pos;
fp = fopen(git_path("MERGE_MSG"), "a");
if (!fp)
die("Could open %s for writing", git_path("MERGE_MSG"));
fprintf(fp, "\nConflicts:\n");
for (pos = 0; pos < active_nr; pos++) {
struct cache_entry *ce = active_cache[pos];
if (ce_stage(ce)) {
fprintf(fp, "\t%s\n", ce->name);
while (pos + 1 < active_nr &&
!strcmp(ce->name,
active_cache[pos + 1]->name))
pos++;
}
}
fclose(fp);
rerere();
printf("Automatic merge failed; "
"fix conflicts and then commit the result.\n");
return 1;
}
static struct commit *is_old_style_invocation(int argc, const char **argv)
{
struct commit *second_token = NULL;
if (argc > 1) {
unsigned char second_sha1[20];
if (get_sha1(argv[1], second_sha1))
return NULL;
second_token = lookup_commit_reference_gently(second_sha1, 0);
if (!second_token)
die("'%s' is not a commit", argv[1]);
if (hashcmp(second_token->object.sha1, head))
return NULL;
}
return second_token;
}
static int evaluate_result(void)
{
int cnt = 0;
struct rev_info rev;
/* Check how many files differ. */
init_revisions(&rev, "");
setup_revisions(0, NULL, &rev, NULL);
rev.diffopt.output_format |=
DIFF_FORMAT_CALLBACK;
rev.diffopt.format_callback = count_diff_files;
rev.diffopt.format_callback_data = &cnt;
run_diff_files(&rev, 0);
/*
* Check how many unmerged entries are
* there.
*/
cnt += count_unmerged_entries();
return cnt;
}
int cmd_merge(int argc, const char **argv, const char *prefix)
{
unsigned char result_tree[20];
struct strbuf buf = STRBUF_INIT;
const char *head_arg;
int flag, head_invalid = 0, i;
int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
struct commit_list *common = NULL;
const char *best_strategy = NULL, *wt_strategy = NULL;
struct commit_list **remotes = &remoteheads;
setup_work_tree();
if (read_cache_unmerged())
die("You are in the middle of a conflicted merge.");
/*
* Check if we are _not_ on a detached HEAD, i.e. if there is a
* current branch.
*/
branch = resolve_ref("HEAD", head, 0, &flag);
if (branch && !prefixcmp(branch, "refs/heads/"))
branch += 11;
if (is_null_sha1(head))
head_invalid = 1;
git_config(git_merge_config, NULL);
/* for color.ui */
if (diff_use_color_default == -1)
diff_use_color_default = git_use_color_default;
argc = parse_options(argc, argv, builtin_merge_options,
builtin_merge_usage, 0);
if (verbosity < 0)
show_diffstat = 0;
if (squash) {
if (!allow_fast_forward)
die("You cannot combine --squash with --no-ff.");
option_commit = 0;
}
if (!argc)
usage_with_options(builtin_merge_usage,
builtin_merge_options);
/*
* This could be traditional "merge <msg> HEAD <commit>..." and
* the way we can tell it is to see if the second token is HEAD,
* but some people might have misused the interface and used a
* committish that is the same as HEAD there instead.
* Traditional format never would have "-m" so it is an
* additional safety measure to check for it.
*/
if (!have_message && is_old_style_invocation(argc, argv)) {
strbuf_addstr(&merge_msg, argv[0]);
head_arg = argv[1];
argv += 2;
argc -= 2;
} else if (head_invalid) {
struct object *remote_head;
/*
* If the merged head is a valid one there is no reason
* to forbid "git merge" into a branch yet to be born.
* We do the same for "git pull".
*/
if (argc != 1)
die("Can merge only exactly one commit into "
"empty head");
if (squash)
die("Squash commit into empty head not supported yet");
if (!allow_fast_forward)
die("Non-fast-forward commit does not make sense into "
"an empty head");
remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
if (!remote_head)
die("%s - not something we can merge", argv[0]);
update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
DIE_ON_ERR);
reset_hard(remote_head->sha1, 0);
return 0;
} else {
struct strbuf msg = STRBUF_INIT;
/* We are invoked directly as the first-class UI. */
head_arg = "HEAD";
/*
* All the rest are the commits being merged;
* prepare the standard merge summary message to
* be appended to the given message. If remote
* is invalid we will die later in the common
* codepath so we discard the error in this
* loop.
*/
for (i = 0; i < argc; i++)
merge_name(argv[i], &msg);
fmt_merge_msg(option_log, &msg, &merge_msg);
if (merge_msg.len)
strbuf_setlen(&merge_msg, merge_msg.len-1);
}
if (head_invalid || !argc)
usage_with_options(builtin_merge_usage,
builtin_merge_options);
strbuf_addstr(&buf, "merge");
for (i = 0; i < argc; i++)
strbuf_addf(&buf, " %s", argv[i]);
setenv("GIT_REFLOG_ACTION", buf.buf, 0);
strbuf_reset(&buf);
for (i = 0; i < argc; i++) {
struct object *o;
struct commit *commit;
o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
if (!o)
die("%s - not something we can merge", argv[i]);
commit = lookup_commit(o->sha1);
commit->util = (void *)argv[i];
remotes = &commit_list_insert(commit, remotes)->next;
strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
setenv(buf.buf, argv[i], 1);
strbuf_reset(&buf);
}
if (!use_strategies) {
if (!remoteheads->next)
add_strategies(pull_twohead, DEFAULT_TWOHEAD);
else
add_strategies(pull_octopus, DEFAULT_OCTOPUS);
}
for (i = 0; i < use_strategies_nr; i++) {
if (use_strategies[i]->attr & NO_FAST_FORWARD)
allow_fast_forward = 0;
if (use_strategies[i]->attr & NO_TRIVIAL)
allow_trivial = 0;
}
if (!remoteheads->next)
common = get_merge_bases(lookup_commit(head),
remoteheads->item, 1);
else {
struct commit_list *list = remoteheads;
commit_list_insert(lookup_commit(head), &list);
common = get_octopus_merge_bases(list);
free(list);
}
update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
DIE_ON_ERR);
if (!common)
; /* No common ancestors found. We need a real merge. */
else if (!remoteheads->next && !common->next &&
common->item == remoteheads->item) {
/*
* If head can reach all the merge then we are up to date.
* but first the most common case of merging one remote.
*/
finish_up_to_date("Already up-to-date.");
return 0;
} else if (allow_fast_forward && !remoteheads->next &&
!common->next &&
!hashcmp(common->item->object.sha1, head)) {
/* Again the most common case of merging one remote. */
struct strbuf msg = STRBUF_INIT;
struct object *o;
char hex[41];