diff options
Diffstat (limited to 'builtin/merge.c')
| -rw-r--r-- | builtin/merge.c | 1513 |
1 files changed, 1513 insertions, 0 deletions
diff --git a/builtin/merge.c b/builtin/merge.c new file mode 100644 index 0000000000..9307e9c726 --- /dev/null +++ b/builtin/merge.c @@ -0,0 +1,1513 @@ +/* + * Builtin "git merge" + * + * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org> + * + * Based on git-merge.sh by Junio C Hamano. + */ + +#include "cache.h" +#include "parse-options.h" +#include "builtin.h" +#include "run-command.h" +#include "diff.h" +#include "refs.h" +#include "commit.h" +#include "diffcore.h" +#include "revision.h" +#include "unpack-trees.h" +#include "cache-tree.h" +#include "dir.h" +#include "utf8.h" +#include "log-tree.h" +#include "color.h" +#include "rerere.h" +#include "help.h" +#include "merge-recursive.h" +#include "resolve-undo.h" +#include "remote.h" +#include "fmt-merge-msg.h" +#include "gpg-interface.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>...]"), + N_("git merge [options] <msg> HEAD <commit>"), + N_("git merge --abort"), + NULL +}; + +static int show_diffstat = 1, shortlog_len = -1, squash; +static int option_commit = 1, allow_fast_forward = 1; +static int fast_forward_only, option_edit = -1; +static int allow_trivial = 1, have_message; +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 option_renormalize; +static int verbosity; +static int allow_rerere_auto; +static int abort_current_merge; +static int show_progress = -1; +static int default_to_upstream; +static const char *sign_commit; + +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%s", buf->len ? "\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); + 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) +{ + show_diffstat = unset; + return 0; +} + +static struct option builtin_merge_options[] = { + { OPTION_CALLBACK, 'n', NULL, NULL, NULL, + N_("do not show a diffstat at the end of the merge"), + PARSE_OPT_NOARG, option_parse_n }, + OPT_BOOLEAN(0, "stat", &show_diffstat, + N_("show a diffstat at the end of the merge")), + OPT_BOOLEAN(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_BOOLEAN(0, "squash", &squash, + N_("create a single commit instead of doing a merge")), + OPT_BOOLEAN(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_BOOLEAN(0, "ff", &allow_fast_forward, + N_("allow fast-forward (default)")), + OPT_BOOLEAN(0, "ff-only", &fast_forward_only, + N_("abort if fast-forward is not possible")), + OPT_RERERE_AUTOUPDATE(&allow_rerere_auto), + 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), + OPT__VERBOSITY(&verbosity), + OPT_BOOLEAN(0, "abort", &abort_current_merge, + N_("abort the current in-progress merge")), + 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_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")), + 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 int save_state(unsigned char *stash) +{ + 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) /* no changes */ + return -1; + strbuf_setlen(&buffer, buffer.len-1); + if (get_sha1(buffer.buf, stash)) + die(_("not a valid object: %s"), buffer.buf); + return 0; +} + +static void read_empty(unsigned const char *sha1, int verbose) +{ + int i = 0; + const char *args[7]; + + args[i++] = "read-tree"; + if (verbose) + args[i++] = "-v"; + args[i++] = "-m"; + args[i++] = "-u"; + args[i++] = EMPTY_TREE_SHA1_HEX; + args[i++] = sha1_to_hex(sha1); + args[i] = NULL; + + if (run_command_v_opt(args, RUN_GIT_CMD)) + die(_("read-tree failed")); +} + +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(const unsigned char *head, + const unsigned char *stash) +{ + 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(struct commit *commit, struct commit_list *remoteheads) +{ + struct rev_info rev; + struct strbuf out = STRBUF_INIT; + struct commit_list *j; + const char *filename; + int fd; + struct pretty_print_context ctx = {0}; + + printf(_("Squash commit -- not updating HEAD\n")); + filename = git_path("SQUASH_MSG"); + fd = open(filename, O_WRONLY | O_CREAT, 0666); + if (fd < 0) + die_errno(_("Could not write to '%s'"), filename); + + init_revisions(&rev, NULL); + rev.ignore_merges = 1; + 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", + sha1_to_hex(commit->object.sha1)); + pretty_print_commit(&ctx, commit, &out); + } + 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(struct commit *head_commit, + struct commit_list *remoteheads, + const unsigned char *new_head, const char *msg) +{ + struct strbuf reflog_message = STRBUF_INIT; + const unsigned char *head = head_commit->object.sha1; + + 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 { + 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.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_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 commit *remote_head; + unsigned char branch_head[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 = 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) { + 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/tags/")) { + strbuf_addf(msg, "%s\t\ttag '%s' of .\n", + sha1_to_hex(branch_head), remote); + goto cleanup; + } + if (!prefixcmp(found_ref, "refs/remotes/")) { + strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n", + sha1_to_hex(branch_head), remote); + goto cleanup; + } + } + + /* See if remote matches <name>^^^.. or <name>~<number> */ + for (len = 0, ptr = remote + strlen(remote); + remote < ptr && ptr[-1] == '^'; + ptr--) + len++; + if (len) + early = 1; + else { + early = 0; + ptr = strrchr(remote, '~'); + if (ptr) { + int seen_nonzero = 0; + + len++; /* count ~ */ + while (*++ptr && isdigit(*ptr)) { + seen_nonzero |= (*ptr != '0'); + len++; + } + if (*ptr) + len = 0; /* not ...~<number> */ + else if (seen_nonzero) + early = 1; + else if (len == 1) + early = 1; /* "name~" is "name~1"! */ + } + } + if (len) { + struct strbuf truname = STRBUF_INIT; + strbuf_addstr(&truname, "refs/heads/"); + strbuf_addstr(&truname, remote); + strbuf_setlen(&truname, truname.len - len); + if (ref_exists(truname.buf)) { + strbuf_addf(msg, + "%s\t\tbranch '%s'%s of .\n", + sha1_to_hex(remote_head->object.sha1), + truname.buf + 11, + (early ? " (early part)" : "")); + strbuf_release(&truname); + goto cleanup; + } + } + + if (!strcmp(remote, "FETCH_HEAD") && + !access(git_path("FETCH_HEAD"), R_OK)) { + const char *filename; + FILE *fp; + struct strbuf line = STRBUF_INIT; + char *ptr; + + filename = git_path("FETCH_HEAD"); + fp = fopen(filename, "r"); + if (!fp) + die_errno(_("could not open '%s' for reading"), + filename); + 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->object.sha1), remote); +cleanup: + strbuf_release(&buf); + 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)); + argv = xrealloc(argv, sizeof(*argv) * (argc + 2)); + memmove(argv + 1, argv, sizeof(*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; + + if (branch && !prefixcmp(k, "branch.") && + !prefixcmp(k + 7, branch) && + !strcmp(k + 7 + strlen(branch), ".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, "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.renormalize")) + option_renormalize = git_config_bool(k, v); + else if (!strcmp(k, "merge.ff")) { + int boolval = git_config_maybe_bool(k, v); + if (0 <= boolval) { + allow_fast_forward = boolval; + } else if (v && !strcmp(v, "only")) { + allow_fast_forward = 1; + fast_forward_only = 1; + } /* 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; + } + + 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(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, + struct commit_list *remoteheads, + struct commit *head, const char *head_arg) +{ + 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, x; + 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; + struct commit_list *j; + + if (remoteheads->next) { + error(_("Not handling anything other than two heads merge.")); + return 2; + } + + init_merge_options(&o); + if (!strcmp(strategy, "subtree")) + o.subtree_shift = ""; + + o.renormalize = option_renormalize; + 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 option for merge-recursive: -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); + + index_fd = hold_locked_index(lock, 1); + clean = merge_recursive(&o, 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 { + return try_merge_command(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 < active_nr; i++) + if (ce_stage(active_cache[i])) + ret++; + + return ret; +} + +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 void write_merge_msg(struct strbuf *msg) +{ + const char *filename = git_path("MERGE_MSG"); + int fd = open(filename, O_WRONLY | O_CREAT, 0666); + if (fd < 0) + die_errno(_("Could not open '%s' for writing"), + filename); + if (write_in_full(fd, msg->buf, msg->len) != msg->len) + die_errno(_("Could not write to '%s'"), filename); + close(fd); +} + +static void read_merge_msg(struct strbuf *msg) +{ + const char *filename = git_path("MERGE_MSG"); + 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" + "Lines starting with '#' will be ignored, and an empty message aborts\n" + "the commit.\n"); + +static void prepare_to_commit(struct commit_list *remoteheads) +{ + struct strbuf msg = STRBUF_INIT; + const char *comment = _(merge_editor_comment); + strbuf_addbuf(&msg, &merge_msg); + strbuf_addch(&msg, '\n'); + if (0 < option_edit) + strbuf_add_lines(&msg, "# ", comment, strlen(comment)); + write_merge_msg(&msg); + if (run_hook(get_index_file(), "prepare-commit-msg", + git_path("MERGE_MSG"), "merge", NULL, NULL)) + abort_commit(remoteheads, NULL); + if (0 < option_edit) { + if (launch_editor(git_path("MERGE_MSG"), NULL, NULL)) + abort_commit(remoteheads, NULL); + } + read_merge_msg(&msg); + stripspace(&msg, 0 < option_edit); + 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) +{ + 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 = head; + parent->next = xmalloc(sizeof(*parent->next)); + parent->next->item = remoteheads->item; + parent->next->next = NULL; + prepare_to_commit(remoteheads); + if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL, + sign_commit)) + die(_("failed to write commit object")); + finish(head, remoteheads, result_commit, "In-index merge"); + drop_save(); + return 0; +} + +static int finish_automerge(struct commit *head, + int head_subsumed, + struct commit_list *common, + struct commit_list *remoteheads, + unsigned char *result_tree, + const char *wt_strategy) +{ + struct commit_list *parents = NULL; + struct strbuf buf = STRBUF_INIT; + unsigned char result_commit[20]; + + free_commit_list(common); + parents = remoteheads; + if (!head_subsumed || !allow_fast_forward) + commit_list_insert(head, &parents); + strbuf_addch(&merge_msg, '\n'); + prepare_to_commit(remoteheads); + if (commit_tree(&merge_msg, 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); + drop_save(); + return 0; +} + +static int suggest_conflicts(int renormalizing) +{ + const char *filename; + FILE *fp; + int pos; + + filename = git_path("MERGE_MSG"); + fp = fopen(filename, "a"); + if (!fp) + die_errno(_("Could not open '%s' for writing"), filename); + 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(allow_rerere_auto); + 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, + const unsigned char *head) +{ + struct commit *second_token = NULL; + if (argc > 2) { + 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; +} + +/* + * Pretend as if the user told us to merge with the 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) + die(_("No remote for the current branch.")); + if (!branch->merge_nr) + die(_("No default upstream defined for the current branch.")); + + args = xcalloc(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_state(struct commit_list *remoteheads) +{ + const char *filename; + int fd; + struct commit_list *j; + struct strbuf buf = STRBUF_INIT; + + for (j = remoteheads; j; j = j->next) { + unsigned const char *sha1; + struct commit *c = j->item; + if (c->util && merge_remote_util(c)->obj) { + sha1 = merge_remote_util(c)->obj->sha1; + } else { + sha1 = c->object.sha1; + } + strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1)); + } + filename = git_path("MERGE_HEAD"); + fd = open(filename, O_WRONLY | O_CREAT, 0666); + if (fd < 0) + die_errno(_("Could not open '%s' for writing"), filename); + if (write_in_full(fd, buf.buf, buf.len) != buf.len) + die_errno(_("Could not write to '%s'"), filename); + close(fd); + strbuf_addch(&merge_msg, '\n'); + write_merge_msg(&merge_msg); + + filename = git_path("MERGE_MODE"); + fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); + if (fd < 0) + die_errno(_("Could not open '%s' for writing"), filename); + 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'"), filename); + close(fd); +} + +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_config_maybe_bool(name, 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 *collect_parents(struct commit *head_commit, + int *head_subsumed, + int argc, const char **argv) +{ + int i; + struct commit_list *remoteheads = NULL, *parents, *next; + struct commit_list **remotes = &remoteheads; + + if (head_commit) + remotes = &commit_list_insert(head_commit, remotes)->next; + for (i = 0; i < argc; i++) { + struct commit *commit = get_merge_parent(argv[i]); + if (!commit) + die(_("%s - not something we can merge"), argv[i]); + remotes = &commit_list_insert(commit, remotes)->next; + } + *remotes = NULL; + + parents = reduce_heads(remoteheads); + + *head_subsumed = 1; /* we will flip this to 0 when we find it */ + for (remoteheads = NULL, remotes = &remoteheads; + parents; + parents = next) { + struct commit *commit = parents->item; + next = parents->next; + if (commit == head_commit) + *head_subsumed = 0; + else + remotes = &commit_list_insert(commit, remotes)->next; + } + return remoteheads; +} + +int cmd_merge(int argc, const char **argv, const char *prefix) +{ + unsigned char result_tree[20]; + unsigned char stash[20]; + unsigned char head_sha1[20]; + struct commit *head_commit; + struct strbuf buf = STRBUF_INIT; + const char *head_arg; + int flag, 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, *p; + void *branch_to_free; + + if (argc == 2 && !strcmp(argv[1], "-h")) + usage_with_options(builtin_merge_usage, builtin_merge_options); + + /* + * Check if we are _not_ on a detached HEAD, i.e. if there is a + * current branch. + */ + branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag); + if (branch && !prefixcmp(branch, "refs/heads/")) + branch += 11; + if (!branch || is_null_sha1(head_sha1)) + head_commit = NULL; + else + head_commit = lookup_commit_or_die(head_sha1, "HEAD"); + + git_config(git_merge_config, NULL); + + 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}; + + if (!file_exists(git_path("MERGE_HEAD"))) + die(_("There is no merge to abort (MERGE_HEAD missing).")); + + /* Invoke 'git reset --merge' */ + ret = cmd_reset(nargc, nargv, prefix); + goto done; + } + + if (read_cache_unmerged()) + die_resolve_conflict("merge"); + + if (file_exists(git_path("MERGE_HEAD"))) { + /* + * There is no unmerged entry, don't advise 'git + * add/rm <file>', just 'git commit'. + */ + if (advice_resolve_conflict) + die(_("You have not concluded your merge (MERGE_HEAD exists).\n" + "Please, commit your changes before you can merge.")); + else + die(_("You have not concluded your merge (MERGE_HEAD exists).")); + } + if (file_exists(git_path("CHERRY_PICK_HEAD"))) { + if (advice_resolve_conflict) + die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n" + "Please, commit your changes before you can merge.")); + else + die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).")); + } + resolve_undo_clear(); + + if (verbosity < 0) + show_diffstat = 0; + + if (squash) { + if (!allow_fast_forward) + die(_("You cannot combine --squash with --no-ff.")); + option_commit = 0; + } + + if (!allow_fast_forward && fast_forward_only) + die(_("You cannot combine --no-ff with --ff-only.")); + + if (!abort_current_merge) { + 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); + + /* + * This could be traditional "merge <msg> HEAD <commit>..." and + * the way we can tell it is to see if the second token is HEAD, + * but some people might have misused the interface and used a + * committish that is the same as HEAD there instead. + * Traditional format never would have "-m" so it is an + * additional safety measure to check for it. + */ + + if (!have_message && head_commit && + is_old_style_invocation(argc, argv, head_commit->object.sha1)) { + strbuf_addstr(&merge_msg, argv[0]); + head_arg = argv[1]; + argv += 2; + argc -= 2; + remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv); + } else if (!head_commit) { + struct commit *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")); + remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv); + remote_head = remoteheads->item; + if (!remote_head) + die(_("%s - not something we can merge"), argv[0]); + read_empty(remote_head->object.sha1, 0); + update_ref("initial pull", "HEAD", remote_head->object.sha1, + NULL, 0, DIE_ON_ERR); + goto done; + } else { + struct strbuf merge_names = 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. + */ + remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv); + for (p = remoteheads; p; p = p->next) + merge_name(merge_remote_util(p->item)->name, &merge_names); + + if (!have_message || shortlog_len) { + 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); + + fmt_merge_msg(&merge_names, &merge_msg, &opts); + if (merge_msg.len) + strbuf_setlen(&merge_msg, merge_msg.len - 1); + } + } + + if (!head_commit || !argc) + usage_with_options(builtin_merge_usage, + builtin_merge_options); + + 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", + sha1_to_hex(commit->object.sha1)); + setenv(buf.buf, merge_remote_util(commit)->name, 1); + strbuf_reset(&buf); + if (!fast_forward_only && + merge_remote_util(commit) && + merge_remote_util(commit)->obj && + merge_remote_util(commit)->obj->type == OBJ_TAG) + allow_fast_forward = 0; + } + + if (option_edit < 0) + option_edit = default_edit_option(); + + 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) + allow_fast_forward = 0; + 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, 1); + 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.sha1, + NULL, 0, DIE_ON_ERR); + + if (remoteheads && !common) + ; /* No common ancestors found. 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("Already up-to-date."); + goto done; + } else if (allow_fast_forward && !remoteheads->next && + !common->next && + !hashcmp(common->item->object.sha1, head_commit->object.sha1)) { + /* Again the most common case of merging one remote. */ + struct strbuf msg = STRBUF_INIT; + struct commit *commit; + char hex[41]; + + strcpy(hex, find_unique_abbrev(head_commit->object.sha1, 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)"); + commit = remoteheads->item; + if (!commit) { + ret = 1; + goto done; + } + + if (checkout_fast_forward(head_commit->object.sha1, + commit->object.sha1, + overwrite_ignore)) { + ret = 1; + goto done; + } + + finish(head_commit, remoteheads, commit->object.sha1, msg.buf); + drop_save(); + 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_cache(REFRESH_QUIET); + if (allow_trivial && !fast_forward_only) { + /* 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.sha1, + head_commit->object.sha1, + remoteheads->item->object.sha1)) { + 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, 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!"); + goto done; + } + } + + if (fast_forward_only) + die(_("Not possible to fast-forward, aborting.")); + + /* 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. + */ + if (use_strategies_nr == 1 || + /* + * Stash away the local changes so that we can try more than one. + */ + save_state(stash)) + hashcpy(stash, null_sha1); + + for (i = 0; i < use_strategies_nr; i++) { + int ret; + if (i) { + printf(_("Rewinding the tree to pristine...\n")); + restore_state(head_commit->object.sha1, 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(use_strategies[i]->name, + common, remoteheads, + head_commit, 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) { + 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.sha1, 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); + 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.sha1, stash); + printf(_("Using the %s to prepare resolving by hand.\n"), + best_strategy); + try_merge_strategy(best_strategy, common, remoteheads, + head_commit, head_arg); + } + + if (squash) + finish(head_commit, remoteheads, NULL, NULL); + 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(option_renormalize); + +done: + free(branch_to_free); + return ret; +} |