diff options
Diffstat (limited to 'builtin/merge.c')
| -rw-r--r-- | builtin/merge.c | 1793 |
1 files changed, 1793 insertions, 0 deletions
diff --git a/builtin/merge.c b/builtin/merge.c new file mode 100644 index 0000000..dd47437 --- /dev/null +++ b/builtin/merge.c @@ -0,0 +1,1793 @@ +/* + * Builtin "git merge" + * + * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org> + * + * Based on git-merge.sh by Junio C Hamano. + */ + +#define USE_THE_INDEX_COMPATIBILITY_MACROS +#include "cache.h" +#include "config.h" +#include "parse-options.h" +#include "builtin.h" +#include "lockfile.h" +#include "run-command.h" +#include "hook.h" +#include "diff.h" +#include "diff-merges.h" +#include "refs.h" +#include "refspec.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" +#include "merge-ort-wrappers.h" +#include "resolve-undo.h" +#include "remote.h" +#include "fmt-merge-msg.h" +#include "gpg-interface.h" +#include "sequencer.h" +#include "string-list.h" +#include "packfile.h" +#include "tag.h" +#include "alias.h" +#include "branch.h" +#include "commit-reach.h" +#include "wt-status.h" +#include "commit-graph.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[] = { + N_("git merge [<options>] [<commit>...]"), + "git merge --abort", + "git merge --continue", + NULL +}; + +static int show_diffstat = 1, shortlog_len = -1, squash; +static int option_commit = -1; +static int option_edit = -1; +static int allow_trivial = 1, have_message, verify_signatures; +static int check_trust_level = 1; +static int overwrite_ignore = 1; +static struct strbuf merge_msg = STRBUF_INIT; +static struct strategy **use_strategies; +static size_t use_strategies_nr, use_strategies_alloc; +static const char **xopts; +static size_t xopts_nr, xopts_alloc; +static const char *branch; +static char *branch_mergeoptions; +static int verbosity; +static int allow_rerere_auto; +static int abort_current_merge; +static int quit_current_merge; +static int continue_current_merge; +static int allow_unrelated_histories; +static int show_progress = -1; +static int default_to_upstream = 1; +static int signoff; +static const char *sign_commit; +static int autostash; +static int no_verify; +static char *into_name; + +static struct strategy all_strategy[] = { + { "recursive", NO_TRIVIAL }, + { "octopus", DEFAULT_OCTOPUS }, + { "ort", DEFAULT_TWOHEAD | NO_TRIVIAL }, + { "resolve", 0 }, + { "ours", NO_FAST_FORWARD | NO_TRIVIAL }, + { "subtree", NO_FAST_FORWARD | NO_TRIVIAL }, +}; + +static const char *pull_twohead, *pull_octopus; + +enum ff_type { + FF_NO, + FF_ALLOW, + FF_ONLY +}; + +static enum ff_type fast_forward = FF_ALLOW; + +static const char *cleanup_arg; +static enum commit_msg_cleanup_mode cleanup_mode; + +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%s", buf->len ? "\n\n" : "", arg); + have_message = 1; + } else + return error(_("switch `m' requires a value")); + return 0; +} + +static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx, + const struct option *opt, + const char *arg_not_used, + int unset) +{ + struct strbuf *buf = opt->value; + const char *arg; + + BUG_ON_OPT_ARG(arg_not_used); + if (unset) + BUG("-F cannot be negated"); + + if (ctx->opt) { + arg = ctx->opt; + ctx->opt = NULL; + } else if (ctx->argc > 1) { + ctx->argc--; + arg = *++ctx->argv; + } else + return error(_("option `%s' requires a value"), opt->long_name); + + if (buf->len) + strbuf_addch(buf, '\n'); + if (ctx->prefix && !is_absolute_path(arg)) + arg = prefix_filename(ctx->prefix, arg); + if (strbuf_read_file(buf, arg, 0) < 0) + return error(_("could not read file '%s'"), arg); + have_message = 1; + + 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; + char *default_strategy = getenv("GIT_TEST_MERGE_ALGORITHM"); + + if (!name) + return NULL; + + if (default_strategy && + !strcmp(default_strategy, "ort") && + !strcmp(name, "recursive")) { + name = "ort"; + } + + 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); + } + + CALLOC_ARRAY(ret, 1); + ret->name = xstrdup(name); + ret->attr = NO_TRIVIAL; + 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_x(const struct option *opt, + const char *arg, int unset) +{ + if (unset) + return 0; + + ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc); + xopts[xopts_nr++] = xstrdup(arg); + return 0; +} + +static int option_parse_n(const struct option *opt, + const char *arg, int unset) +{ + BUG_ON_OPT_ARG(arg); + show_diffstat = unset; + return 0; +} + +static struct option builtin_merge_options[] = { + OPT_CALLBACK_F('n', NULL, NULL, NULL, + N_("do not show a diffstat at the end of the merge"), + PARSE_OPT_NOARG, option_parse_n), + OPT_BOOL(0, "stat", &show_diffstat, + N_("show a diffstat at the end of the merge")), + OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")), + { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"), + N_("add (at most <n>) entries from shortlog to merge commit message"), + PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN }, + OPT_BOOL(0, "squash", &squash, + N_("create a single commit instead of doing a merge")), + OPT_BOOL(0, "commit", &option_commit, + N_("perform a commit if the merge succeeds (default)")), + OPT_BOOL('e', "edit", &option_edit, + N_("edit message before committing")), + OPT_CLEANUP(&cleanup_arg), + OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW), + OPT_SET_INT_F(0, "ff-only", &fast_forward, + N_("abort if fast-forward is not possible"), + FF_ONLY, PARSE_OPT_NONEG), + OPT_RERERE_AUTOUPDATE(&allow_rerere_auto), + OPT_BOOL(0, "verify-signatures", &verify_signatures, + N_("verify that the named commit has a valid GPG signature")), + OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"), + N_("merge strategy to use"), option_parse_strategy), + OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"), + N_("option for selected merge strategy"), option_parse_x), + OPT_CALLBACK('m', "message", &merge_msg, N_("message"), + N_("merge commit message (for a non-fast-forward merge)"), + option_parse_message), + { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"), + N_("read message from file"), PARSE_OPT_NONEG, + NULL, 0, option_read_message }, + OPT_STRING(0, "into-name", &into_name, N_("name"), + N_("use <name> instead of the real target")), + OPT__VERBOSITY(&verbosity), + OPT_BOOL(0, "abort", &abort_current_merge, + N_("abort the current in-progress merge")), + OPT_BOOL(0, "quit", &quit_current_merge, + N_("--abort but leave index and working tree alone")), + OPT_BOOL(0, "continue", &continue_current_merge, + N_("continue the current in-progress merge")), + OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories, + N_("allow merging unrelated histories")), + OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1), + { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"), + N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" }, + OPT_AUTOSTASH(&autostash), + OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")), + OPT_BOOL(0, "signoff", &signoff, N_("add a Signed-off-by trailer")), + OPT_BOOL(0, "no-verify", &no_verify, N_("bypass pre-merge-commit and commit-msg hooks")), + OPT_END() +}; + +static int save_state(struct object_id *stash) +{ + int len; + struct child_process cp = CHILD_PROCESS_INIT; + struct strbuf buffer = STRBUF_INIT; + struct lock_file lock_file = LOCK_INIT; + int fd; + int rc = -1; + + fd = repo_hold_locked_index(the_repository, &lock_file, 0); + refresh_index(&the_index, REFRESH_QUIET, NULL, NULL, NULL); + if (0 <= fd) + repo_update_index_if_able(the_repository, &lock_file); + rollback_lock_file(&lock_file); + + strvec_pushl(&cp.args, "stash", "create", NULL); + 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) /* no changes */ + goto out; + strbuf_setlen(&buffer, buffer.len-1); + if (get_oid(buffer.buf, stash)) + die(_("not a valid object: %s"), buffer.buf); + rc = 0; +out: + strbuf_release(&buffer); + return rc; +} + +static void read_empty(const struct object_id *oid) +{ + struct child_process cmd = CHILD_PROCESS_INIT; + + strvec_pushl(&cmd.args, "read-tree", "-m", "-u", empty_tree_oid_hex(), + oid_to_hex(oid), NULL); + cmd.git_cmd = 1; + + if (run_command(&cmd)) + die(_("read-tree failed")); +} + +static void reset_hard(const struct object_id *oid) +{ + struct child_process cmd = CHILD_PROCESS_INIT; + + strvec_pushl(&cmd.args, "read-tree", "-v", "--reset", "-u", + oid_to_hex(oid), NULL); + cmd.git_cmd = 1; + + if (run_command(&cmd)) + die(_("read-tree failed")); +} + +static void restore_state(const struct object_id *head, + const struct object_id *stash) +{ + struct child_process cmd = CHILD_PROCESS_INIT; + + reset_hard(head); + + if (is_null_oid(stash)) + goto refresh_cache; + + strvec_pushl(&cmd.args, "stash", "apply", "--index", "--quiet", NULL); + strvec_push(&cmd.args, oid_to_hex(stash)); + + /* + * It is OK to ignore error here, for example when there was + * nothing to restore. + */ + cmd.git_cmd = 1; + run_command(&cmd); + +refresh_cache: + discard_cache(); + if (read_cache() < 0) + die(_("could not read index")); +} + +/* This is called when no merge was necessary. */ +static void finish_up_to_date(void) +{ + if (verbosity >= 0) { + if (squash) + puts(_("Already up to date. (nothing to squash)")); + else + puts(_("Already up to date.")); + } + remove_merge_branch_state(the_repository); +} + +static void squash_message(struct commit *commit, struct commit_list *remoteheads) +{ + struct rev_info rev; + struct strbuf out = STRBUF_INIT; + struct commit_list *j; + struct pretty_print_context ctx = {0}; + + printf(_("Squash commit -- not updating HEAD\n")); + + repo_init_revisions(the_repository, &rev, NULL); + diff_merges_suppress(&rev); + rev.commit_format = CMIT_FMT_MEDIUM; + + 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; + ctx.fmt = rev.commit_format; + + 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", + oid_to_hex(&commit->object.oid)); + pretty_print_commit(&ctx, commit, &out); + } + write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len); + strbuf_release(&out); + release_revisions(&rev); +} + +static void finish(struct commit *head_commit, + struct commit_list *remoteheads, + const struct object_id *new_head, const char *msg) +{ + struct strbuf reflog_message = STRBUF_INIT; + const struct object_id *head = &head_commit->object.oid; + + 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(head_commit, remoteheads); + } else { + if (verbosity >= 0 && !merge_msg.len) + printf(_("No merge message -- not updating HEAD\n")); + else { + update_ref(reflog_message.buf, "HEAD", new_head, head, + 0, UPDATE_REFS_DIE_ON_ERR); + /* + * We ignore errors in 'gc --auto', since the + * user should see them. + */ + run_auto_maintenance(verbosity < 0); + } + } + if (new_head && show_diffstat) { + struct diff_options opts; + repo_diff_setup(the_repository, &opts); + opts.stat_width = -1; /* use full terminal width */ + opts.stat_graph_width = -1; /* respect statGraphWidth config */ + opts.output_format |= + DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT; + opts.detect_rename = DIFF_DETECT_RENAME; + diff_setup_done(&opts); + diff_tree_oid(head, new_head, "", &opts); + diffcore_std(&opts); + diff_flush(&opts); + } + + /* Run a post-merge hook */ + run_hooks_l("post-merge", squash ? "1" : "0", NULL); + + if (new_head) + apply_autostash(git_path_merge_autostash(the_repository)); + strbuf_release(&reflog_message); +} + +/* Get the name for the merge commit's message. */ +static void merge_name(const char *remote, struct strbuf *msg) +{ + struct commit *remote_head; + struct object_id branch_head; + struct strbuf bname = STRBUF_INIT; + struct merge_remote_desc *desc; + const char *ptr; + char *found_ref = NULL; + int len, early; + + strbuf_branchname(&bname, remote, 0); + remote = bname.buf; + + oidclr(&branch_head); + remote_head = get_merge_parent(remote); + if (!remote_head) + die(_("'%s' does not point to a commit"), remote); + + if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref, 0) > 0) { + if (starts_with(found_ref, "refs/heads/")) { + strbuf_addf(msg, "%s\t\tbranch '%s' of .\n", + oid_to_hex(&branch_head), remote); + goto cleanup; + } + if (starts_with(found_ref, "refs/tags/")) { + strbuf_addf(msg, "%s\t\ttag '%s' of .\n", + oid_to_hex(&branch_head), remote); + goto cleanup; + } + if (starts_with(found_ref, "refs/remotes/")) { + strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n", + oid_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_addf(&truname, "refs/heads/%s", remote); + strbuf_setlen(&truname, truname.len - len); + if (ref_exists(truname.buf)) { + strbuf_addf(msg, + "%s\t\tbranch '%s'%s of .\n", + oid_to_hex(&remote_head->object.oid), + truname.buf + 11, + (early ? " (early part)" : "")); + strbuf_release(&truname); + goto cleanup; + } + strbuf_release(&truname); + } + + desc = merge_remote_util(remote_head); + if (desc && desc->obj && desc->obj->type == OBJ_TAG) { + strbuf_addf(msg, "%s\t\t%s '%s'\n", + oid_to_hex(&desc->obj->oid), + type_name(desc->obj->type), + remote); + goto cleanup; + } + + strbuf_addf(msg, "%s\t\tcommit '%s'\n", + oid_to_hex(&remote_head->object.oid), remote); +cleanup: + free(found_ref); + strbuf_release(&bname); +} + +static void parse_branch_merge_options(char *bmo) +{ + const char **argv; + int argc; + + if (!bmo) + return; + argc = split_cmdline(bmo, &argv); + if (argc < 0) + die(_("Bad branch.%s.mergeoptions string: %s"), branch, + _(split_cmdline_strerror(argc))); + REALLOC_ARRAY(argv, argc + 2); + MOVE_ARRAY(argv + 1, argv, argc + 1); + argc++; + argv[0] = "branch.*.mergeoptions"; + parse_options(argc, argv, NULL, builtin_merge_options, + builtin_merge_usage, 0); + free(argv); +} + +static int git_merge_config(const char *k, const char *v, void *cb) +{ + int status; + const char *str; + + if (branch && + skip_prefix(k, "branch.", &str) && + skip_prefix(str, branch, &str) && + !strcmp(str, ".mergeoptions")) { + free(branch_mergeoptions); + branch_mergeoptions = xstrdup(v); + return 0; + } + + if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat")) + show_diffstat = git_config_bool(k, v); + else if (!strcmp(k, "merge.verifysignatures")) + verify_signatures = 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, "commit.cleanup")) + return git_config_string(&cleanup_arg, k, v); + else if (!strcmp(k, "merge.ff")) { + int boolval = git_parse_maybe_bool(v); + if (0 <= boolval) { + fast_forward = boolval ? FF_ALLOW : FF_NO; + } else if (v && !strcmp(v, "only")) { + fast_forward = FF_ONLY; + } /* do not barf on values from future versions of git */ + return 0; + } else if (!strcmp(k, "merge.defaulttoupstream")) { + default_to_upstream = git_config_bool(k, v); + return 0; + } else if (!strcmp(k, "commit.gpgsign")) { + sign_commit = git_config_bool(k, v) ? "" : NULL; + return 0; + } else if (!strcmp(k, "gpg.mintrustlevel")) { + check_trust_level = 0; + } else if (!strcmp(k, "merge.autostash")) { + autostash = git_config_bool(k, v); + return 0; + } + + status = fmt_merge_msg_config(k, v, cb); + if (status) + return status; + status = git_gpg_config(k, v, NULL); + if (status) + return status; + return git_diff_ui_config(k, v, cb); +} + +static int read_tree_trivial(struct object_id *common, struct object_id *head, + struct object_id *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; + opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */ + 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(&the_index.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(struct object_id *oid) +{ + if (write_cache_as_tree(oid, 0, NULL)) + die(_("git write-tree failed to write a tree")); +} + +static int try_merge_strategy(const char *strategy, struct commit_list *common, + struct commit_list *remoteheads, + struct commit *head) +{ + const char *head_arg = "HEAD"; + + if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET, + SKIP_IF_UNCHANGED, 0, NULL, NULL, + NULL) < 0) + return error(_("Unable to write index.")); + + if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree") || + !strcmp(strategy, "ort")) { + struct lock_file lock = LOCK_INIT; + int clean, x; + struct commit *result; + struct commit_list *reversed = NULL; + struct merge_options o; + struct commit_list *j; + + if (remoteheads->next) { + error(_("Not handling anything other than two heads merge.")); + return 2; + } + + init_merge_options(&o, the_repository); + if (!strcmp(strategy, "subtree")) + o.subtree_shift = ""; + + o.show_rename_progress = + show_progress == -1 ? isatty(2) : show_progress; + + for (x = 0; x < xopts_nr; x++) + if (parse_merge_opt(&o, xopts[x])) + die(_("unknown strategy option: -X%s"), xopts[x]); + + o.branch1 = head_arg; + o.branch2 = merge_remote_util(remoteheads->item)->name; + + for (j = common; j; j = j->next) + commit_list_insert(j->item, &reversed); + + repo_hold_locked_index(the_repository, &lock, + LOCK_DIE_ON_ERROR); + if (!strcmp(strategy, "ort")) + clean = merge_ort_recursive(&o, head, remoteheads->item, + reversed, &result); + else + clean = merge_recursive(&o, head, remoteheads->item, + reversed, &result); + if (clean < 0) { + rollback_lock_file(&lock); + return 2; + } + if (write_locked_index(&the_index, &lock, + COMMIT_LOCK | SKIP_IF_UNCHANGED)) + die(_("unable to write %s"), get_index_file()); + return clean ? 0 : 1; + } else { + return try_merge_command(the_repository, + strategy, xopts_nr, xopts, + common, head_arg, remoteheads); + } +} + +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) +{ + int i, ret = 0; + + for (i = 0; i < the_index.cache_nr; i++) + if (ce_stage(the_index.cache[i])) + ret++; + + return ret; +} + +static void add_strategies(const char *string, unsigned attr) +{ + int i; + + if (string) { + struct string_list list = STRING_LIST_INIT_DUP; + struct string_list_item *item; + string_list_split(&list, string, ' ', -1); + for_each_string_list_item(item, &list) + append_strategy(get_strategy(item->string)); + string_list_clear(&list, 0); + return; + } + for (i = 0; i < ARRAY_SIZE(all_strategy); i++) + if (all_strategy[i].attr & attr) + append_strategy(&all_strategy[i]); + +} + +static void read_merge_msg(struct strbuf *msg) +{ + const char *filename = git_path_merge_msg(the_repository); + strbuf_reset(msg); + if (strbuf_read_file(msg, filename, 0) < 0) + die_errno(_("Could not read from '%s'"), filename); +} + +static void write_merge_state(struct commit_list *); +static void abort_commit(struct commit_list *remoteheads, const char *err_msg) +{ + if (err_msg) + error("%s", err_msg); + fprintf(stderr, + _("Not committing merge; use 'git commit' to complete the merge.\n")); + write_merge_state(remoteheads); + exit(1); +} + +static const char merge_editor_comment[] = +N_("Please enter a commit message to explain why this merge is necessary,\n" + "especially if it merges an updated upstream into a topic branch.\n" + "\n"); + +static const char scissors_editor_comment[] = +N_("An empty message aborts the commit.\n"); + +static const char no_scissors_editor_comment[] = +N_("Lines starting with '%c' will be ignored, and an empty message aborts\n" + "the commit.\n"); + +static void write_merge_heads(struct commit_list *); +static void prepare_to_commit(struct commit_list *remoteheads) +{ + struct strbuf msg = STRBUF_INIT; + const char *index_file = get_index_file(); + + if (!no_verify) { + int invoked_hook; + + if (run_commit_hook(0 < option_edit, index_file, &invoked_hook, + "pre-merge-commit", NULL)) + abort_commit(remoteheads, NULL); + /* + * Re-read the index as pre-merge-commit hook could have updated it, + * and write it out as a tree. We must do this before we invoke + * the editor and after we invoke run_status above. + */ + if (invoked_hook) + discard_index(&the_index); + } + read_index_from(&the_index, index_file, get_git_dir()); + strbuf_addbuf(&msg, &merge_msg); + if (squash) + BUG("the control must not reach here under --squash"); + if (0 < option_edit) { + strbuf_addch(&msg, '\n'); + if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) { + wt_status_append_cut_line(&msg); + strbuf_commented_addf(&msg, "\n"); + } + strbuf_commented_addf(&msg, _(merge_editor_comment)); + if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) + strbuf_commented_addf(&msg, _(scissors_editor_comment)); + else + strbuf_commented_addf(&msg, + _(no_scissors_editor_comment), comment_line_char); + } + if (signoff) + append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0); + write_merge_heads(remoteheads); + write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len); + if (run_commit_hook(0 < option_edit, get_index_file(), NULL, + "prepare-commit-msg", + git_path_merge_msg(the_repository), "merge", NULL)) + abort_commit(remoteheads, NULL); + if (0 < option_edit) { + if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL)) + abort_commit(remoteheads, NULL); + } + + if (!no_verify && run_commit_hook(0 < option_edit, get_index_file(), + NULL, "commit-msg", + git_path_merge_msg(the_repository), NULL)) + abort_commit(remoteheads, NULL); + + read_merge_msg(&msg); + cleanup_message(&msg, cleanup_mode, 0); + if (!msg.len) + abort_commit(remoteheads, _("Empty commit message.")); + strbuf_release(&merge_msg); + strbuf_addbuf(&merge_msg, &msg); + strbuf_release(&msg); +} + +static int merge_trivial(struct commit *head, struct commit_list *remoteheads) +{ + struct object_id result_tree, result_commit; + struct commit_list *parents, **pptr = &parents; + + if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET, + SKIP_IF_UNCHANGED, 0, NULL, NULL, + NULL) < 0) + return error(_("Unable to write index.")); + + write_tree_trivial(&result_tree); + printf(_("Wonderful.\n")); + pptr = commit_list_append(head, pptr); + pptr = commit_list_append(remoteheads->item, pptr); + prepare_to_commit(remoteheads); + if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents, + &result_commit, NULL, sign_commit)) + die(_("failed to write commit object")); + finish(head, remoteheads, &result_commit, "In-index merge"); + remove_merge_branch_state(the_repository); + return 0; +} + +static int finish_automerge(struct commit *head, + int head_subsumed, + struct commit_list *common, + struct commit_list *remoteheads, + struct object_id *result_tree, + const char *wt_strategy) +{ + struct commit_list *parents = NULL; + struct strbuf buf = STRBUF_INIT; + struct object_id result_commit; + + write_tree_trivial(result_tree); + free_commit_list(common); + parents = remoteheads; + if (!head_subsumed || fast_forward == FF_NO) + commit_list_insert(head, &parents); + prepare_to_commit(remoteheads); + if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents, + &result_commit, NULL, sign_commit)) + die(_("failed to write commit object")); + strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy); + finish(head, remoteheads, &result_commit, buf.buf); + strbuf_release(&buf); + remove_merge_branch_state(the_repository); + return 0; +} + +static int suggest_conflicts(void) +{ + const char *filename; + FILE *fp; + struct strbuf msgbuf = STRBUF_INIT; + + filename = git_path_merge_msg(the_repository); + fp = xfopen(filename, "a"); + + /* + * We can't use cleanup_mode because if we're not using the editor, + * get_cleanup_mode will return COMMIT_MSG_CLEANUP_SPACE instead, even + * though the message is meant to be processed later by git-commit. + * Thus, we will get the cleanup mode which is returned when we _are_ + * using an editor. + */ + append_conflicts_hint(&the_index, &msgbuf, + get_cleanup_mode(cleanup_arg, 1)); + fputs(msgbuf.buf, fp); + strbuf_release(&msgbuf); + fclose(fp); + repo_rerere(the_repository, allow_rerere_auto); + printf(_("Automatic merge failed; " + "fix conflicts and then commit the result.\n")); + return 1; +} + +static int evaluate_result(void) +{ + int cnt = 0; + struct rev_info rev; + + /* Check how many files differ. */ + repo_init_revisions(the_repository, &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(); + + release_revisions(&rev); + return cnt; +} + +/* + * Pretend as if the user told us to merge with the remote-tracking + * branch we have for the upstream of the current branch + */ +static int setup_with_upstream(const char ***argv) +{ + struct branch *branch = branch_get(NULL); + int i; + const char **args; + + if (!branch) + die(_("No current branch.")); + if (!branch->remote_name) + die(_("No remote for the current branch.")); + if (!branch->merge_nr) + die(_("No default upstream defined for the current branch.")); + + args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *)); + for (i = 0; i < branch->merge_nr; i++) { + if (!branch->merge[i]->dst) + die(_("No remote-tracking branch for %s from %s"), + branch->merge[i]->src, branch->remote_name); + args[i] = branch->merge[i]->dst; + } + args[i] = NULL; + *argv = args; + return i; +} + +static void write_merge_heads(struct commit_list *remoteheads) +{ + struct commit_list *j; + struct strbuf buf = STRBUF_INIT; + + for (j = remoteheads; j; j = j->next) { + struct object_id *oid; + struct commit *c = j->item; + struct merge_remote_desc *desc; + + desc = merge_remote_util(c); + if (desc && desc->obj) { + oid = &desc->obj->oid; + } else { + oid = &c->object.oid; + } + strbuf_addf(&buf, "%s\n", oid_to_hex(oid)); + } + write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len); + + strbuf_reset(&buf); + if (fast_forward == FF_NO) + strbuf_addstr(&buf, "no-ff"); + write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len); + strbuf_release(&buf); +} + +static void write_merge_state(struct commit_list *remoteheads) +{ + write_merge_heads(remoteheads); + strbuf_addch(&merge_msg, '\n'); + write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf, + merge_msg.len); +} + +static int default_edit_option(void) +{ + static const char name[] = "GIT_MERGE_AUTOEDIT"; + const char *e = getenv(name); + struct stat st_stdin, st_stdout; + + if (have_message) + /* an explicit -m msg without --[no-]edit */ + return 0; + + if (e) { + int v = git_parse_maybe_bool(e); + if (v < 0) + die(_("Bad value '%s' in environment '%s'"), e, name); + return v; + } + + /* Use editor if stdin and stdout are the same and is a tty */ + return (!fstat(0, &st_stdin) && + !fstat(1, &st_stdout) && + isatty(0) && isatty(1) && + st_stdin.st_dev == st_stdout.st_dev && + st_stdin.st_ino == st_stdout.st_ino && + st_stdin.st_mode == st_stdout.st_mode); +} + +static struct commit_list *reduce_parents(struct commit *head_commit, + int *head_subsumed, + struct commit_list *remoteheads) +{ + struct commit_list *parents, **remotes; + + /* + * Is the current HEAD reachable from another commit being + * merged? If so we do not want to record it as a parent of + * the resulting merge, unless --no-ff is given. We will flip + * this variable to 0 when we find HEAD among the independent + * tips being merged. + */ + *head_subsumed = 1; + + /* Find what parents to record by checking independent ones. */ + parents = reduce_heads(remoteheads); + free_commit_list(remoteheads); + + remoteheads = NULL; + remotes = &remoteheads; + while (parents) { + struct commit *commit = pop_commit(&parents); + if (commit == head_commit) + *head_subsumed = 0; + else + remotes = &commit_list_insert(commit, remotes)->next; + } + return remoteheads; +} + +static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg) +{ + struct fmt_merge_msg_opts opts; + + memset(&opts, 0, sizeof(opts)); + opts.add_title = !have_message; + opts.shortlog_len = shortlog_len; + opts.credit_people = (0 < option_edit); + opts.into_name = into_name; + + fmt_merge_msg(merge_names, merge_msg, &opts); + if (merge_msg->len) + strbuf_setlen(merge_msg, merge_msg->len - 1); +} + +static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names) +{ + const char *filename; + int fd, pos, npos; + struct strbuf fetch_head_file = STRBUF_INIT; + const unsigned hexsz = the_hash_algo->hexsz; + + if (!merge_names) + merge_names = &fetch_head_file; + + filename = git_path_fetch_head(the_repository); + fd = xopen(filename, O_RDONLY); + + if (strbuf_read(merge_names, fd, 0) < 0) + die_errno(_("could not read '%s'"), filename); + if (close(fd) < 0) + die_errno(_("could not close '%s'"), filename); + + for (pos = 0; pos < merge_names->len; pos = npos) { + struct object_id oid; + char *ptr; + struct commit *commit; + + ptr = strchr(merge_names->buf + pos, '\n'); + if (ptr) + npos = ptr - merge_names->buf + 1; + else + npos = merge_names->len; + + if (npos - pos < hexsz + 2 || + get_oid_hex(merge_names->buf + pos, &oid)) + commit = NULL; /* bad */ + else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2)) + continue; /* not-for-merge */ + else { + char saved = merge_names->buf[pos + hexsz]; + merge_names->buf[pos + hexsz] = '\0'; + commit = get_merge_parent(merge_names->buf + pos); + merge_names->buf[pos + hexsz] = saved; + } + if (!commit) { + if (ptr) + *ptr = '\0'; + die(_("not something we can merge in %s: %s"), + filename, merge_names->buf + pos); + } + remotes = &commit_list_insert(commit, remotes)->next; + } + + if (merge_names == &fetch_head_file) + strbuf_release(&fetch_head_file); +} + +static struct commit_list *collect_parents(struct commit *head_commit, + int *head_subsumed, + int argc, const char **argv, + struct strbuf *merge_msg) +{ + int i; + struct commit_list *remoteheads = NULL; + struct commit_list **remotes = &remoteheads; + struct strbuf merge_names = STRBUF_INIT, *autogen = NULL; + + if (merge_msg && (!have_message || shortlog_len)) + autogen = &merge_names; + + if (head_commit) + remotes = &commit_list_insert(head_commit, remotes)->next; + + if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) { + handle_fetch_head(remotes, autogen); + remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads); + } else { + for (i = 0; i < argc; i++) { + struct commit *commit = get_merge_parent(argv[i]); + if (!commit) + help_unknown_ref(argv[i], "merge", + _("not something we can merge")); + remotes = &commit_list_insert(commit, remotes)->next; + } + remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads); + if (autogen) { + struct commit_list *p; + for (p = remoteheads; p; p = p->next) + merge_name(merge_remote_util(p->item)->name, autogen); + } + } + + if (autogen) { + prepare_merge_message(autogen, merge_msg); + strbuf_release(autogen); + } + + return remoteheads; +} + +static int merging_a_throwaway_tag(struct commit *commit) +{ + char *tag_ref; + struct object_id oid; + int is_throwaway_tag = 0; + + /* Are we merging a tag? */ + if (!merge_remote_util(commit) || + !merge_remote_util(commit)->obj || + merge_remote_util(commit)->obj->type != OBJ_TAG) + return is_throwaway_tag; + + /* + * Now we know we are merging a tag object. Are we downstream + * and following the tags from upstream? If so, we must have + * the tag object pointed at by "refs/tags/$T" where $T is the + * tagname recorded in the tag object. We want to allow such + * a "just to catch up" merge to fast-forward. + * + * Otherwise, we are playing an integrator's role, making a + * merge with a throw-away tag from a contributor with + * something like "git pull $contributor $signed_tag". + * We want to forbid such a merge from fast-forwarding + * by default; otherwise we would not keep the signature + * anywhere. + */ + tag_ref = xstrfmt("refs/tags/%s", + ((struct tag *)merge_remote_util(commit)->obj)->tag); + if (!read_ref(tag_ref, &oid) && + oideq(&oid, &merge_remote_util(commit)->obj->oid)) + is_throwaway_tag = 0; + else + is_throwaway_tag = 1; + free(tag_ref); + return is_throwaway_tag; +} + +int cmd_merge(int argc, const char **argv, const char *prefix) +{ + struct object_id result_tree, stash, head_oid; + struct commit *head_commit; + struct strbuf buf = STRBUF_INIT; + int i, ret = 0, head_subsumed; + 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 *remoteheads = NULL, *p; + void *branch_to_free; + int orig_argc = argc; + + if (argc == 2 && !strcmp(argv[1], "-h")) + usage_with_options(builtin_merge_usage, builtin_merge_options); + + prepare_repo_settings(the_repository); + the_repository->settings.command_requires_full_index = 0; + + /* + * Check if we are _not_ on a detached HEAD, i.e. if there is a + * current branch. + */ + branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL); + if (branch) + skip_prefix(branch, "refs/heads/", &branch); + + if (!pull_twohead) { + char *default_strategy = getenv("GIT_TEST_MERGE_ALGORITHM"); + if (default_strategy && !strcmp(default_strategy, "ort")) + pull_twohead = "ort"; + } + + init_diff_ui_defaults(); + git_config(git_merge_config, NULL); + + if (!branch || is_null_oid(&head_oid)) + head_commit = NULL; + else + head_commit = lookup_commit_or_die(&head_oid, "HEAD"); + + if (branch_mergeoptions) + parse_branch_merge_options(branch_mergeoptions); + argc = parse_options(argc, argv, prefix, builtin_merge_options, + builtin_merge_usage, 0); + if (shortlog_len < 0) + shortlog_len = (merge_log_config > 0) ? merge_log_config : 0; + + if (verbosity < 0 && show_progress == -1) + show_progress = 0; + + if (abort_current_merge) { + int nargc = 2; + const char *nargv[] = {"reset", "--merge", NULL}; + struct strbuf stash_oid = STRBUF_INIT; + + if (orig_argc != 2) + usage_msg_opt(_("--abort expects no arguments"), + builtin_merge_usage, builtin_merge_options); + + if (!file_exists(git_path_merge_head(the_repository))) + die(_("There is no merge to abort (MERGE_HEAD missing).")); + + if (read_oneliner(&stash_oid, git_path_merge_autostash(the_repository), + READ_ONELINER_SKIP_IF_EMPTY)) + unlink(git_path_merge_autostash(the_repository)); + + /* Invoke 'git reset --merge' */ + ret = cmd_reset(nargc, nargv, prefix); + + if (stash_oid.len) + apply_autostash_oid(stash_oid.buf); + + strbuf_release(&stash_oid); + goto done; + } + + if (quit_current_merge) { + if (orig_argc != 2) + usage_msg_opt(_("--quit expects no arguments"), + builtin_merge_usage, + builtin_merge_options); + + remove_merge_branch_state(the_repository); + goto done; + } + + if (continue_current_merge) { + int nargc = 1; + const char *nargv[] = {"commit", NULL}; + + if (orig_argc != 2) + usage_msg_opt(_("--continue expects no arguments"), + builtin_merge_usage, builtin_merge_options); + + if (!file_exists(git_path_merge_head(the_repository))) + die(_("There is no merge in progress (MERGE_HEAD missing).")); + + /* Invoke 'git commit' */ + ret = cmd_commit(nargc, nargv, prefix); + goto done; + } + + if (repo_read_index_unmerged(the_repository)) + die_resolve_conflict("merge"); + + if (file_exists(git_path_merge_head(the_repository))) { + /* + * There is no unmerged entry, don't advise 'git + * add/rm <file>', just 'git commit'. + */ + if (advice_enabled(ADVICE_RESOLVE_CONFLICT)) + die(_("You have not concluded your merge (MERGE_HEAD exists).\n" + "Please, commit your changes before you merge.")); + else + die(_("You have not concluded your merge (MERGE_HEAD exists).")); + } + if (ref_exists("CHERRY_PICK_HEAD")) { + if (advice_enabled(ADVICE_RESOLVE_CONFLICT)) + die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n" + "Please, commit your changes before you merge.")); + else + die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).")); + } + resolve_undo_clear_index(&the_index); + + if (option_edit < 0) + option_edit = default_edit_option(); + + cleanup_mode = get_cleanup_mode(cleanup_arg, 0 < option_edit); + + if (verbosity < 0) + show_diffstat = 0; + + if (squash) { + if (fast_forward == FF_NO) + die(_("options '%s' and '%s' cannot be used together"), "--squash", "--no-ff."); + if (option_commit > 0) + die(_("options '%s' and '%s' cannot be used together"), "--squash", "--commit."); + /* + * squash can now silently disable option_commit - this is not + * a problem as it is only overriding the default, not a user + * supplied option. + */ + option_commit = 0; + } + + if (option_commit < 0) + option_commit = 1; + + if (!argc) { + if (default_to_upstream) + argc = setup_with_upstream(&argv); + else + die(_("No commit specified and merge.defaultToUpstream not set.")); + } else if (argc == 1 && !strcmp(argv[0], "-")) { + argv[0] = "@{-1}"; + } + + if (!argc) + usage_with_options(builtin_merge_usage, + builtin_merge_options); + + if (!head_commit) { + /* + * 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". + */ + struct object_id *remote_head_oid; + if (squash) + die(_("Squash commit into empty head not supported yet")); + if (fast_forward == FF_NO) + die(_("Non-fast-forward commit does not make sense into " + "an empty head")); + remoteheads = collect_parents(head_commit, &head_subsumed, + argc, argv, NULL); + if (!remoteheads) + die(_("%s - not something we can merge"), argv[0]); + if (remoteheads->next) + die(_("Can merge only exactly one commit into empty head")); + + if (verify_signatures) + verify_merge_signature(remoteheads->item, verbosity, + check_trust_level); + + remote_head_oid = &remoteheads->item->object.oid; + read_empty(remote_head_oid); + update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0, + UPDATE_REFS_DIE_ON_ERR); + goto done; + } + + /* + * All the rest are the commits being merged; prepare + * the standard merge summary message to be appended + * to the given message. + */ + remoteheads = collect_parents(head_commit, &head_subsumed, + argc, argv, &merge_msg); + + if (!head_commit || !argc) + usage_with_options(builtin_merge_usage, + builtin_merge_options); + + if (verify_signatures) { + for (p = remoteheads; p; p = p->next) { + verify_merge_signature(p->item, verbosity, + check_trust_level); + } + } + + strbuf_addstr(&buf, "merge"); + for (p = remoteheads; p; p = p->next) + strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name); + setenv("GIT_REFLOG_ACTION", buf.buf, 0); + strbuf_reset(&buf); + + for (p = remoteheads; p; p = p->next) { + struct commit *commit = p->item; + strbuf_addf(&buf, "GITHEAD_%s", + oid_to_hex(&commit->object.oid)); + setenv(buf.buf, merge_remote_util(commit)->name, 1); + strbuf_reset(&buf); + if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit)) + fast_forward = FF_NO; + } + + if (!use_strategies && !pull_twohead && + remoteheads && !remoteheads->next) { + char *default_strategy = getenv("GIT_TEST_MERGE_ALGORITHM"); + if (default_strategy) + append_strategy(get_strategy(default_strategy)); + } + if (!use_strategies) { + if (!remoteheads) + ; /* already up-to-date */ + else 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) + fast_forward = FF_NO; + if (use_strategies[i]->attr & NO_TRIVIAL) + allow_trivial = 0; + } + + if (!remoteheads) + ; /* already up-to-date */ + else if (!remoteheads->next) + common = get_merge_bases(head_commit, remoteheads->item); + else { + struct commit_list *list = remoteheads; + commit_list_insert(head_commit, &list); + common = get_octopus_merge_bases(list); + free(list); + } + + update_ref("updating ORIG_HEAD", "ORIG_HEAD", + &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR); + + if (remoteheads && !common) { + /* No common ancestors found. */ + if (!allow_unrelated_histories) + die(_("refusing to merge unrelated histories")); + /* otherwise, we need a real merge. */ + } else if (!remoteheads || + (!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(); + goto done; + } else if (fast_forward != FF_NO && !remoteheads->next && + !common->next && + oideq(&common->item->object.oid, &head_commit->object.oid)) { + /* Again the most common case of merging one remote. */ + struct strbuf msg = STRBUF_INIT; + struct commit *commit; + + if (verbosity >= 0) { + printf(_("Updating %s..%s\n"), + find_unique_abbrev(&head_commit->object.oid, + DEFAULT_ABBREV), + find_unique_abbrev(&remoteheads->item->object.oid, + DEFAULT_ABBREV)); + } + strbuf_addstr(&msg, "Fast-forward"); + if (have_message) + strbuf_addstr(&msg, + " (no commit created; -m option ignored)"); + commit = remoteheads->item; + if (!commit) { + ret = 1; + goto done; + } + + if (autostash) + create_autostash(the_repository, + git_path_merge_autostash(the_repository)); + if (checkout_fast_forward(the_repository, + &head_commit->object.oid, + &commit->object.oid, + overwrite_ignore)) { + apply_autostash(git_path_merge_autostash(the_repository)); + ret = 1; + goto done; + } + + finish(head_commit, remoteheads, &commit->object.oid, msg.buf); + remove_merge_branch_state(the_repository); + strbuf_release(&msg); + goto done; + } 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_index(&the_index, REFRESH_QUIET, NULL, NULL, NULL); + if (allow_trivial && fast_forward != FF_ONLY) { + /* + * Must first ensure that index matches HEAD before + * attempting a trivial merge. + */ + struct tree *head_tree = get_commit_tree(head_commit); + struct strbuf sb = STRBUF_INIT; + + if (repo_index_has_changes(the_repository, head_tree, + &sb)) { + error(_("Your local changes to the following files would be overwritten by merge:\n %s"), + sb.buf); + strbuf_release(&sb); + return 2; + } + + /* See if it is really trivial. */ + git_committer_info(IDENT_STRICT); + printf(_("Trying really trivial in-index merge...\n")); + if (!read_tree_trivial(&common->item->object.oid, + &head_commit->object.oid, + &remoteheads->item->object.oid)) { + ret = merge_trivial(head_commit, remoteheads); + goto done; + } + 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(head_commit, j->item); + if (!oideq(&common_one->item->object.oid, &j->item->object.oid)) { + up_to_date = 0; + break; + } + } + if (up_to_date) { + finish_up_to_date(); + goto done; + } + } + + if (fast_forward == FF_ONLY) + die_ff_impossible(); + + if (autostash) + create_autostash(the_repository, + git_path_merge_autostash(the_repository)); + + /* We are going to make a new commit. */ + git_committer_info(IDENT_STRICT); + + /* + * 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. + * + * Stash away the local changes so that we can try more than one + * and/or recover from merge strategies bailing while leaving the + * index and working tree polluted. + */ + if (save_state(&stash)) + oidclr(&stash); + + for (i = 0; i < use_strategies_nr; i++) { + int ret, cnt; + if (i) { + printf(_("Rewinding the tree to pristine...\n")); + restore_state(&head_commit->object.oid, &stash); + } + 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(wt_strategy, + common, remoteheads, + head_commit); + /* + * 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 < 2) { + if (!ret) { + /* + * This strategy worked; no point in trying + * another. + */ + merge_was_ok = 1; + best_strategy = wt_strategy; + break; + } + cnt = (use_strategies_nr > 1) ? evaluate_result() : 0; + if (best_cnt <= 0 || cnt <= best_cnt) { + best_strategy = wt_strategy; + best_cnt = cnt; + } + } + } + + /* + * If we have a resulting tree, that means the strategy module + * auto resolved the merge cleanly. + */ + if (merge_was_ok && option_commit) { + automerge_was_ok = 1; + ret = finish_automerge(head_commit, head_subsumed, + common, remoteheads, + &result_tree, wt_strategy); + goto done; + } + + /* + * Pick the result from the best strategy and have the user fix + * it up. + */ + if (!best_strategy) { + restore_state(&head_commit->object.oid, &stash); + 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); + apply_autostash(git_path_merge_autostash(the_repository)); + ret = 2; + goto done; + } 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(&head_commit->object.oid, &stash); + printf(_("Using the %s strategy to prepare resolving by hand.\n"), + best_strategy); + try_merge_strategy(best_strategy, common, remoteheads, + head_commit); + } + + if (squash) { + finish(head_commit, remoteheads, NULL, NULL); + + git_test_write_commit_graph_or_die(); + } else + write_merge_state(remoteheads); + + if (merge_was_ok) + fprintf(stderr, _("Automatic merge went well; " + "stopped before committing as requested\n")); + else + ret = suggest_conflicts(); + if (autostash) + printf(_("When finished, apply stashed changes with `git stash pop`\n")); + +done: + if (!automerge_was_ok) { + free_commit_list(common); + free_commit_list(remoteheads); + } + strbuf_release(&buf); + free(branch_to_free); + return ret; +} |