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-rw-r--r--builtin/merge.c1614
1 files changed, 1614 insertions, 0 deletions
diff --git a/builtin/merge.c b/builtin/merge.c
new file mode 100644
index 0000000000..470fc57c5d
--- /dev/null
+++ b/builtin/merge.c
@@ -0,0 +1,1614 @@
+/*
+ * 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[] = {
+ "git merge [options] [<commit>...]",
+ "git merge [options] <msg> HEAD <commit>",
+ "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(&not_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(&not_strategies, ent->name, ent->len);
+ }
+ exclude_cmds(&main_cmds, &not_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,
+ "do not show a diffstat at the end of the merge",
+ PARSE_OPT_NOARG, option_parse_n },
+ OPT_BOOLEAN(0, "stat", &show_diffstat,
+ "show a diffstat at the end of the merge"),
+ OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
+ { OPTION_INTEGER, 0, "log", &shortlog_len, "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,
+ "create a single commit instead of doing a merge"),
+ OPT_BOOLEAN(0, "commit", &option_commit,
+ "perform a commit if the merge succeeds (default)"),
+ OPT_BOOL('e', "edit", &option_edit,
+ "edit message before committing"),
+ OPT_BOOLEAN(0, "ff", &allow_fast_forward,
+ "allow fast-forward (default)"),
+ OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
+ "abort if fast-forward is not possible"),
+ OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
+ OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
+ "merge strategy to use", option_parse_strategy),
+ OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
+ "option for selected merge strategy", option_parse_x),
+ OPT_CALLBACK('m', "message", &merge_msg, "message",
+ "merge commit message (for a non-fast-forward merge)",
+ option_parse_message),
+ OPT__VERBOSITY(&verbosity),
+ OPT_BOOLEAN(0, "abort", &abort_current_merge,
+ "abort the current in-progress merge"),
+ OPT_SET_INT(0, "progress", &show_progress, "force progress reporting", 1),
+ { OPTION_STRING, 'S', "gpg-sign", &sign_commit, "key id",
+ "GPG sign commit", PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
+ OPT_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, "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;
+ if (diff_setup_done(&opts) < 0)
+ die(_("diff_setup_done failed"));
+ diff_tree_sha1(head, new_head, "", &opts);
+ diffcore_std(&opts);
+ diff_flush(&opts);
+ }
+
+ /* Run a post-merge hook */
+ run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
+
+ strbuf_release(&reflog_message);
+}
+
+/* Get the name for the merge commit's message. */
+static void merge_name(const char *remote, struct strbuf *msg)
+{
+ struct 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 const char *merge_argument(struct commit *commit)
+{
+ if (commit)
+ return sha1_to_hex(commit->object.sha1);
+ else
+ return EMPTY_TREE_SHA1_HEX;
+}
+
+int try_merge_command(const char *strategy, size_t xopts_nr,
+ const char **xopts, struct commit_list *common,
+ const char *head_arg, struct commit_list *remotes)
+{
+ const char **args;
+ int i = 0, x = 0, ret;
+ struct commit_list *j;
+ struct strbuf buf = STRBUF_INIT;
+
+ args = xmalloc((4 + xopts_nr + commit_list_count(common) +
+ commit_list_count(remotes)) * sizeof(char *));
+ strbuf_addf(&buf, "merge-%s", strategy);
+ args[i++] = buf.buf;
+ for (x = 0; x < xopts_nr; x++) {
+ char *s = xmalloc(strlen(xopts[x])+2+1);
+ strcpy(s, "--");
+ strcpy(s+2, xopts[x]);
+ args[i++] = s;
+ }
+ for (j = common; j; j = j->next)
+ args[i++] = xstrdup(merge_argument(j->item));
+ args[i++] = "--";
+ args[i++] = head_arg;
+ for (j = remotes; j; j = j->next)
+ args[i++] = xstrdup(merge_argument(j->item));
+ args[i] = NULL;
+ ret = run_command_v_opt(args, RUN_GIT_CMD);
+ strbuf_release(&buf);
+ i = 1;
+ for (x = 0; x < xopts_nr; x++)
+ free((void *)args[i++]);
+ for (j = common; j; j = j->next)
+ free((void *)args[i++]);
+ i += 2;
+ for (j = remotes; j; j = j->next)
+ free((void *)args[i++]);
+ free(args);
+ discard_cache();
+ if (read_cache() < 0)
+ die(_("failed to read the cache"));
+ resolve_undo_clear();
+
+ return ret;
+}
+
+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;
+}
+
+int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
+{
+ struct tree *trees[MAX_UNPACK_TREES];
+ struct unpack_trees_options opts;
+ struct tree_desc t[MAX_UNPACK_TREES];
+ int i, fd, nr_trees = 0;
+ struct dir_struct dir;
+ struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+
+ refresh_cache(REFRESH_QUIET);
+
+ fd = hold_locked_index(lock_file, 1);
+
+ memset(&trees, 0, sizeof(trees));
+ memset(&opts, 0, sizeof(opts));
+ memset(&t, 0, sizeof(t));
+ if (overwrite_ignore) {
+ memset(&dir, 0, sizeof(dir));
+ dir.flags |= DIR_SHOW_IGNORED;
+ setup_standard_excludes(&dir);
+ opts.dir = &dir;
+ }
+
+ opts.head_idx = 1;
+ opts.src_index = &the_index;
+ opts.dst_index = &the_index;
+ opts.update = 1;
+ opts.verbose_update = 1;
+ opts.merge = 1;
+ opts.fn = twoway_merge;
+ setup_unpack_trees_porcelain(&opts, "merge");
+
+ trees[nr_trees] = parse_tree_indirect(head);
+ if (!trees[nr_trees++])
+ return -1;
+ trees[nr_trees] = parse_tree_indirect(remote);
+ if (!trees[nr_trees++])
+ return -1;
+ for (i = 0; i < nr_trees; i++) {
+ parse_tree(trees[i]);
+ init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
+ }
+ if (unpack_trees(nr_trees, t, &opts))
+ return -1;
+ if (write_cache(fd, active_cache, active_nr) ||
+ commit_locked_index(lock_file))
+ die(_("unable to write new index file"));
+ return 0;
+}
+
+static void split_merge_strategies(const char *string, struct strategy **list,
+ int *nr, int *alloc)
+{
+ char *p, *q, *buf;
+
+ if (!string)
+ return;
+
+ buf = xstrdup(string);
+ q = buf;
+ for (;;) {
+ p = strchr(q, ' ');
+ if (!p) {
+ ALLOC_GROW(*list, *nr + 1, *alloc);
+ (*list)[(*nr)++].name = xstrdup(q);
+ free(buf);
+ return;
+ } else {
+ *p = '\0';
+ ALLOC_GROW(*list, *nr + 1, *alloc);
+ (*list)[(*nr)++].name = xstrdup(q);
+ q = ++p;
+ }
+ }
+}
+
+static void add_strategies(const char *string, unsigned attr)
+{
+ struct strategy *list = NULL;
+ int list_alloc = 0, list_nr = 0, i;
+
+ memset(&list, 0, sizeof(list));
+ split_merge_strategies(string, &list, &list_nr, &list_alloc);
+ if (list) {
+ for (i = 0; i < list_nr; i++)
+ append_strategy(get_strategy(list[i].name));
+ return;
+ }
+ for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
+ if (all_strategy[i].attr & attr)
+ append_strategy(&all_strategy[i]);
+
+}
+
+static 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);
+ run_hook(get_index_file(), "prepare-commit-msg",
+ git_path("MERGE_MSG"), "merge", NULL, 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;
+
+ 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)) {
+ 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_ERROR_ON_NO_NAME);
+ 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_ERROR_ON_NO_NAME);
+
+ /*
+ * At this point, we need a real merge. No matter what strategy
+ * we use, it would operate on the index, possibly affecting the
+ * working tree, and when resolved cleanly, have the desired
+ * tree in the index -- this means that the index must be in
+ * sync with the head commit. The strategies are responsible
+ * to ensure this.
+ */
+ if (use_strategies_nr == 1 ||
+ /*
+ * Stash away the local changes so that we can try more than one.
+ */
+ save_state(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;
+}