diff options
Diffstat (limited to 'builtin-merge.c')
| -rw-r--r-- | builtin-merge.c | 1156 |
1 files changed, 1156 insertions, 0 deletions
diff --git a/builtin-merge.c b/builtin-merge.c new file mode 100644 index 0000000000..129b4e62dd --- /dev/null +++ b/builtin-merge.c @@ -0,0 +1,1156 @@ +/* + * 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" + +#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 struct strategy all_strategy[] = { + { "recur", NO_TRIVIAL }, + { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL }, + { "octopus", DEFAULT_OCTOPUS }, + { "resolve", 0 }, + { "stupid", 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 { + strbuf_addf(buf, "%s\n\n", arg); + have_message = 1; + } + return 0; +} + +static struct strategy *get_strategy(const char *name) +{ + int i; + + if (!name) + return NULL; + + for (i = 0; i < ARRAY_SIZE(all_strategy); i++) + if (!strcmp(name, all_strategy[i].name)) + return &all_strategy[i]; + return NULL; +} + +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) +{ + int i; + struct strategy *s; + + if (unset) + return 0; + + s = get_strategy(name); + + if (s) + append_strategy(s); + else { + struct strbuf err; + strbuf_init(&err, 0); + for (i = 0; i < ARRAY_SIZE(all_strategy); i++) + strbuf_addf(&err, " %s", all_strategy[i].name); + fprintf(stderr, "Could not find merge strategy '%s'.\n", name); + fprintf(stderr, "Available strategies are:%s.\n", err.buf); + exit(1); + } + 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_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")); +} + +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; + const char *args[] = { "stash", "apply", NULL, NULL }; + + if (is_null_sha1(stash)) + return; + + reset_hard(head, 1); + + strbuf_init(&sb, 0); + 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) +{ + 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; + 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_init(&out, 0); + 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); + } + write(fd, out.buf, out.len); + close(fd); + strbuf_release(&out); +} + +static int run_hook(const char *name) +{ + struct child_process hook; + const char *argv[3], *env[2]; + char index[PATH_MAX]; + + argv[0] = git_path("hooks/%s", name); + if (access(argv[0], X_OK) < 0) + return 0; + + snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file()); + env[0] = index; + env[1] = NULL; + + if (squash) + argv[1] = "1"; + else + argv[1] = "0"; + argv[2] = NULL; + + memset(&hook, 0, sizeof(hook)); + hook.argv = argv; + hook.no_stdin = 1; + hook.stdout_to_stderr = 1; + hook.env = env; + + return run_command(&hook); +} + +static void finish(const unsigned char *new_head, const char *msg) +{ + struct strbuf reflog_message; + + strbuf_init(&reflog_message, 0); + if (!msg) + strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION")); + else { + printf("%s\n", msg); + strbuf_addf(&reflog_message, "%s: %s", + getenv("GIT_REFLOG_ACTION"), msg); + } + if (squash) { + squash_message(); + } else { + if (!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("post-merge"); + + 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; + const char *ptr; + int len, early; + + 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_init(&buf, 0); + 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); + return; + } + + /* 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, len+11); + 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, + (early ? " (early part)" : "")); + return; + } + } + + if (!strcmp(remote, "FETCH_HEAD") && + !access(git_path("FETCH_HEAD"), R_OK)) { + FILE *fp; + struct strbuf line; + char *ptr; + + strbuf_init(&line, 0); + 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); + return; + } + strbuf_addf(msg, "%s\t\tcommit '%s'\n", + sha1_to_hex(remote_head->sha1), remote); +} + +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); + 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; + + args = xmalloc((4 + commit_list_count(common) + + commit_list_count(remoteheads)) * sizeof(char *)); + strbuf_init(&buf, 0); + 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); + 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)); + + if (read_cache_unmerged()) + die("you need to resolve your current index first"); + + fd = hold_locked_index(lock_file, 1); + + memset(&trees, 0, sizeof(trees)); + memset(&opts, 0, sizeof(opts)); + memset(&t, 0, sizeof(t)); + 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 != NULL) { + for (i = 0; i < list_nr; i++) { + struct strategy *s; + + s = get_strategy(list[i].name); + if (s) + append_strategy(s); + } + 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; + + write_tree_trivial(result_tree); + printf("Wonderful.\n"); + parent.item = remoteheads->item; + parent.next = NULL; + commit_tree(merge_msg.buf, result_tree, &parent, result_commit); + 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); + 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; + + if (read_cache() < 0) + die("failed to read the cache"); + + /* 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; + 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 (unmerged_cache()) + 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 (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. + */ + strbuf_init(&buf, 0); + + 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"); + 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; + + /* 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. + */ + strbuf_init(&msg, 0); + 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; + + o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT); + if (!o) + die("%s - not something we can merge", argv[i]); + remotes = &commit_list_insert(lookup_commit(o->sha1), + 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; + struct object *o; + char hex[41]; + + strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV)); + + printf("Updating %s..%s\n", + hex, + find_unique_abbrev(remoteheads->item->object.sha1, + DEFAULT_ABBREV)); + refresh_cache(REFRESH_QUIET); + strbuf_init(&msg, 0); + strbuf_addstr(&msg, "Fast forward"); + if (have_message) + strbuf_addstr(&msg, + " (no commit created; -m option ignored)"); + o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1), + 0, NULL, OBJ_COMMIT); + if (!o) + return 1; + + if (checkout_fast_forward(head, remoteheads->item->object.sha1)) + return 1; + + finish(o->sha1, msg.buf); + drop_save(); + return 0; + } else if (!remoteheads->next && common->next) + ; + /* + * We are not doing octopus and not fast forward. Need + * a real merge. + */ + else if (!remoteheads->next && !common->next && option_commit) { + /* + * We are not doing octopus, not fast forward, and have + * only one common. + */ + refresh_cache(REFRESH_QUIET); + if (allow_trivial) { + /* See if it is really trivial. */ + git_committer_info(IDENT_ERROR_ON_NO_NAME); + printf("Trying really trivial in-index merge...\n"); + if (!read_tree_trivial(common->item->object.sha1, + head, remoteheads->item->object.sha1)) + return merge_trivial(); + printf("Nope.\n"); + } + } else { + /* + * An octopus. If we can reach all the remote we are up + * to date. + */ + int up_to_date = 1; + struct commit_list *j; + + for (j = remoteheads; j; j = j->next) { + struct commit_list *common_one; + + /* + * Here we *have* to calculate the individual + * merge_bases again, otherwise "git merge HEAD^ + * HEAD^^" would be missed. + */ + common_one = get_merge_bases(lookup_commit(head), + j->item, 1); + if (hashcmp(common_one->item->object.sha1, + j->item->object.sha1)) { + up_to_date = 0; + break; + } + } + if (up_to_date) { + finish_up_to_date("Already up-to-date. Yeeah!"); + return 0; + } + } + + /* We are going to make a new commit. */ + git_committer_info(IDENT_ERROR_ON_NO_NAME); + + /* + * At this point, we need a real merge. No matter what strategy + * we use, it would operate on the index, possibly affecting the + * working tree, and when resolved cleanly, have the desired + * tree in the index -- this means that the index must be in + * sync with the head commit. The strategies are responsible + * to ensure this. + */ + if (use_strategies_nr != 1) { + /* + * Stash away the local changes so that we can try more + * than one. + */ + save_state(); + } else { + memcpy(stash, null_sha1, 20); + } + + for (i = 0; i < use_strategies_nr; i++) { + int ret; + if (i) { + printf("Rewinding the tree to pristine...\n"); + restore_state(); + } + if (use_strategies_nr != 1) + printf("Trying merge strategy %s...\n", + use_strategies[i]->name); + /* + * Remember which strategy left the state in the working + * tree. + */ + wt_strategy = use_strategies[i]->name; + + ret = try_merge_strategy(use_strategies[i]->name, + common, head_arg); + if (!option_commit && !ret) { + merge_was_ok = 1; + /* + * This is necessary here just to avoid writing + * the tree, but later we will *not* exit with + * status code 1 because merge_was_ok is set. + */ + ret = 1; + } + + if (ret) { + /* + * The backend exits with 1 when conflicts are + * left to be resolved, with 2 when it does not + * handle the given merge at all. + */ + if (ret == 1) { + int cnt = evaluate_result(); + + if (best_cnt <= 0 || cnt <= best_cnt) { + best_strategy = use_strategies[i]->name; + best_cnt = cnt; + } + } + if (merge_was_ok) + break; + else + continue; + } + + /* Automerge succeeded. */ + write_tree_trivial(result_tree); + automerge_was_ok = 1; + break; + } + + /* + * If we have a resulting tree, that means the strategy module + * auto resolved the merge cleanly. + */ + if (automerge_was_ok) + return finish_automerge(common, result_tree, wt_strategy); + + /* + * Pick the result from the best strategy and have the user fix + * it up. + */ + if (!best_strategy) { + restore_state(); + if (use_strategies_nr > 1) + fprintf(stderr, + "No merge strategy handled the merge.\n"); + else + fprintf(stderr, "Merge with strategy %s failed.\n", + use_strategies[0]->name); + return 2; + } else if (best_strategy == wt_strategy) + ; /* We already have its result in the working tree. */ + else { + printf("Rewinding the tree to pristine...\n"); + restore_state(); + printf("Using the %s to prepare resolving by hand.\n", + best_strategy); + try_merge_strategy(best_strategy, common, head_arg); + } + + if (squash) + finish(NULL, NULL); + else { + int fd; + struct commit_list *j; + + for (j = remoteheads; j; j = j->next) + strbuf_addf(&buf, "%s\n", + sha1_to_hex(j->item->object.sha1)); + fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666); + if (fd < 0) + die("Could open %s for writing", + git_path("MERGE_HEAD")); + if (write_in_full(fd, buf.buf, buf.len) != buf.len) + die("Could not write to %s", git_path("MERGE_HEAD")); + close(fd); + strbuf_addch(&merge_msg, '\n'); + fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666); + if (fd < 0) + die("Could open %s for writing", git_path("MERGE_MSG")); + if (write_in_full(fd, merge_msg.buf, merge_msg.len) != + merge_msg.len) + die("Could not write to %s", git_path("MERGE_MSG")); + close(fd); + } + + if (merge_was_ok) { + fprintf(stderr, "Automatic merge went well; " + "stopped before committing as requested\n"); + return 0; + } else + return suggest_conflicts(); +} |