/* * Builtin "git merge" * * Copyright (c) 2008 Miklos Vajna * * 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] ...", "git merge [options] HEAD ", 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; struct pretty_print_context ctx = {0}; printf("Squash commit -- not updating HEAD\n"); fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666); if (fd < 0) die_errno("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"); ctx.abbrev = rev.abbrev; ctx.date_mode = rev.date_mode; 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, &ctx); } if (write(fd, out.buf, out.len) < 0) die_errno("Writing SQUASH_MSG"); if (close(fd)) die_errno("Finishing SQUASH_MSG"); 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; char *found_ref; int len, early; strbuf_branchname(&bname, remote); 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); if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) { if (!prefixcmp(found_ref, "refs/heads/")) { strbuf_addf(msg, "%s\t\tbranch '%s' of .\n", sha1_to_hex(branch_head), remote); goto cleanup; } if (!prefixcmp(found_ref, "refs/remotes/")) { strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n", sha1_to_hex(branch_head), remote); goto cleanup; } } /* See if remote matches ^^^.. or ~ */ 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 ...~ */ 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, NULL)) { 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_errno("could not open '%s' for reading", git_path("FETCH_HEAD")); 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, NULL, 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.flags |= DIR_SHOW_IGNORED; 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_errno("Could not 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; if (file_exists(git_path("MERGE_HEAD"))) die("You have not concluded your merge. (MERGE_HEAD exists)"); if (read_cache_unmerged()) die("You are in the middle of a conflicted merge." " (index unmerged)"); /* * 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, prefix, 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 HEAD ..." 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]; strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV)); if (verbosity >= 0) printf("Updating %s..%s\n", hex, find_unique_abbrev(remoteheads->item->object.sha1, DEFAULT_ABBREV)); 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_errno("Could not open '%s' for writing", git_path("MERGE_HEAD")); if (write_in_full(fd, buf.buf, buf.len) != buf.len) die_errno("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_errno("Could not open '%s' for writing", git_path("MERGE_MSG")); if (write_in_full(fd, merge_msg.buf, merge_msg.len) != merge_msg.len) die_errno("Could not write to '%s'", git_path("MERGE_MSG")); close(fd); fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666); if (fd < 0) die_errno("Could not open '%s' for writing", git_path("MERGE_MODE")); strbuf_reset(&buf); if (!allow_fast_forward) strbuf_addf(&buf, "no-ff"); if (write_in_full(fd, buf.buf, buf.len) != buf.len) die_errno("Could not write to '%s'", git_path("MERGE_MODE")); close(fd); } if (merge_was_ok) { fprintf(stderr, "Automatic merge went well; " "stopped before committing as requested\n"); return 0; } else return suggest_conflicts(); }