clone: factor out HEAD update code
[gitweb.git] / builtin / merge.c
index c6e3e7fdaf92dc94925283ee5470588625c7df48..4b0ca6550c130dc8efbf248c56503018b8bcb604 100644 (file)
@@ -25,6 +25,8 @@
 #include "help.h"
 #include "merge-recursive.h"
 #include "resolve-undo.h"
+#include "remote.h"
+#include "fmt-merge-msg.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -37,25 +39,31 @@ struct strategy {
 };
 
 static const char * const builtin_merge_usage[] = {
-       "git merge [options] <remote>...",
-       "git merge [options] <msg> HEAD <remote>",
+       "git merge [options] [<commit>...]",
+       "git merge [options] <msg> HEAD <commit>",
+       "git merge --abort",
        NULL
 };
 
-static int show_diffstat = 1, option_log, squash;
+static int show_diffstat = 1, shortlog_len = -1, squash;
 static int option_commit = 1, allow_fast_forward = 1;
-static int fast_forward_only;
+static int fast_forward_only, option_edit;
 static int allow_trivial = 1, have_message;
+static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
 static struct commit_list *remoteheads;
-static unsigned char head[20], stash[20];
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
 static const char **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 struct strategy all_strategy[] = {
        { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
@@ -78,7 +86,7 @@ static int option_parse_message(const struct option *opt,
                strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
                have_message = 1;
        } else
-               return error("switch `m' requires a value");
+               return error(_("switch `m' requires a value"));
        return 0;
 }
 
@@ -115,13 +123,13 @@ static struct strategy *get_strategy(const char *name)
                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:");
+               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:");
+                       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");
@@ -131,6 +139,7 @@ static struct strategy *get_strategy(const char *name)
 
        ret = xcalloc(1, sizeof(struct strategy));
        ret->name = xstrdup(name);
+       ret->attr = NO_TRIVIAL;
        return ret;
 }
 
@@ -175,12 +184,15 @@ static struct option builtin_merge_options[] = {
        OPT_BOOLEAN(0, "stat", &show_diffstat,
                "show a diffstat at the end of the merge"),
        OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
-       OPT_BOOLEAN(0, "log", &option_log,
-               "add list of one-line log to merge commit message"),
+       { 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_BOOLEAN('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,
@@ -191,9 +203,13 @@ static struct option builtin_merge_options[] = {
        OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
                "option for selected merge strategy", option_parse_x),
        OPT_CALLBACK('m', "message", &merge_msg, "message",
-               "message to be used for the merge commit (if any)",
+               "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),
+       OPT_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, "update ignored files (default)"),
        OPT_END()
 };
 
@@ -205,7 +221,7 @@ static void drop_save(void)
        unlink(git_path("MERGE_MODE"));
 }
 
-static void save_state(void)
+static int save_state(unsigned char *stash)
 {
        int len;
        struct child_process cp;
@@ -218,17 +234,36 @@ static void save_state(void)
        cp.git_cmd = 1;
 
        if (start_command(&cp))
-               die("could not run stash.");
+               die(_("could not run stash."));
        len = strbuf_read(&buffer, cp.out, 1024);
        close(cp.out);
 
        if (finish_command(&cp) || len < 0)
-               die("stash failed");
-       else if (!len)
-               return;
+               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);
+               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)
@@ -245,10 +280,11 @@ static void reset_hard(unsigned const char *sha1, int verbose)
        args[i] = NULL;
 
        if (run_command_v_opt(args, RUN_GIT_CMD))
-               die("read-tree failed");
+               die(_("read-tree failed"));
 }
 
-static void restore_state(void)
+static void restore_state(const unsigned char *head,
+                         const unsigned char *stash)
 {
        struct strbuf sb = STRBUF_INIT;
        const char *args[] = { "stash", "apply", NULL, NULL };
@@ -274,29 +310,29 @@ static void restore_state(void)
 static void finish_up_to_date(const char *msg)
 {
        if (verbosity >= 0)
-               printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
+               printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
        drop_save();
 }
 
-static void squash_message(void)
+static void squash_message(struct commit *commit)
 {
        struct rev_info rev;
-       struct commit *commit;
        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");
-       fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
+       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'", git_path("SQUASH_MSG"));
+               die_errno(_("Could not write to '%s'"), filename);
 
        init_revisions(&rev, NULL);
        rev.ignore_merges = 1;
        rev.commit_format = CMIT_FMT_MEDIUM;
 
-       commit = lookup_commit(head);
        commit->object.flags |= UNINTERESTING;
        add_pending_object(&rev, &commit->object, NULL);
 
@@ -305,28 +341,31 @@ static void squash_message(void)
 
        setup_revisions(0, NULL, &rev, NULL);
        if (prepare_revision_walk(&rev))
-               die("revision walk setup failed");
+               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(rev.commit_format, commit, &out, &ctx);
+               pretty_print_commit(&ctx, commit, &out);
        }
        if (write(fd, out.buf, out.len) < 0)
-               die_errno("Writing SQUASH_MSG");
+               die_errno(_("Writing SQUASH_MSG"));
        if (close(fd))
-               die_errno("Finishing SQUASH_MSG");
+               die_errno(_("Finishing SQUASH_MSG"));
        strbuf_release(&out);
 }
 
-static void finish(const unsigned char *new_head, const char *msg)
+static void finish(struct commit *head_commit,
+                  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"));
@@ -337,10 +376,10 @@ static void finish(const unsigned char *new_head, const char *msg)
                        getenv("GIT_REFLOG_ACTION"), msg);
        }
        if (squash) {
-               squash_message();
+               squash_message(head_commit);
        } else {
                if (verbosity >= 0 && !merge_msg.len)
-                       printf("No merge message -- not updating HEAD\n");
+                       printf(_("No merge message -- not updating HEAD\n"));
                else {
                        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
                        update_ref(reflog_message.buf, "HEAD",
@@ -359,10 +398,8 @@ static void finish(const unsigned char *new_head, const char *msg)
                opts.output_format |=
                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
                opts.detect_rename = DIFF_DETECT_RENAME;
-               if (diff_use_color_default > 0)
-                       DIFF_OPT_SET(&opts, COLOR_DIFF);
                if (diff_setup_done(&opts) < 0)
-                       die("diff_setup_done failed");
+                       die(_("diff_setup_done failed"));
                diff_tree_sha1(head, new_head, "", &opts);
                diffcore_std(&opts);
                diff_flush(&opts);
@@ -377,8 +414,8 @@ static void finish(const unsigned char *new_head, const char *msg)
 /* Get the name for the merge commit's message. */
 static void merge_name(const char *remote, struct strbuf *msg)
 {
-       struct object *remote_head;
-       unsigned char branch_head[20], buf_sha[20];
+       struct commit *remote_head;
+       unsigned char branch_head[20];
        struct strbuf buf = STRBUF_INIT;
        struct strbuf bname = STRBUF_INIT;
        const char *ptr;
@@ -389,9 +426,9 @@ static void merge_name(const char *remote, struct strbuf *msg)
        remote = bname.buf;
 
        memset(branch_head, 0, sizeof(branch_head));
-       remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
+       remote_head = get_merge_parent(remote);
        if (!remote_head)
-               die("'%s' does not point to a commit", remote);
+               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/")) {
@@ -399,8 +436,13 @@ static void merge_name(const char *remote, struct strbuf *msg)
                                    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 branch '%s' of .\n",
+                       strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
                                    sha1_to_hex(branch_head), remote);
                        goto cleanup;
                }
@@ -437,10 +479,10 @@ static void merge_name(const char *remote, struct strbuf *msg)
                strbuf_addstr(&truname, "refs/heads/");
                strbuf_addstr(&truname, remote);
                strbuf_setlen(&truname, truname.len - len);
-               if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
+               if (ref_exists(truname.buf)) {
                        strbuf_addf(msg,
                                    "%s\t\tbranch '%s'%s of .\n",
-                                   sha1_to_hex(remote_head->sha1),
+                                   sha1_to_hex(remote_head->object.sha1),
                                    truname.buf + 11,
                                    (early ? " (early part)" : ""));
                        strbuf_release(&truname);
@@ -450,14 +492,16 @@ static void merge_name(const char *remote, struct strbuf *msg)
 
        if (!strcmp(remote, "FETCH_HEAD") &&
                        !access(git_path("FETCH_HEAD"), R_OK)) {
+               const char *filename;
                FILE *fp;
                struct strbuf line = STRBUF_INIT;
                char *ptr;
 
-               fp = fopen(git_path("FETCH_HEAD"), "r");
+               filename = git_path("FETCH_HEAD");
+               fp = fopen(filename, "r");
                if (!fp)
-                       die_errno("could not open '%s' for reading",
-                                 git_path("FETCH_HEAD"));
+                       die_errno(_("could not open '%s' for reading"),
+                                 filename);
                strbuf_getline(&line, fp, '\n');
                fclose(fp);
                ptr = strstr(line.buf, "\tnot-for-merge\t");
@@ -468,31 +512,42 @@ static void merge_name(const char *remote, struct strbuf *msg)
                goto cleanup;
        }
        strbuf_addf(msg, "%s\t\tcommit '%s'\n",
-               sha1_to_hex(remote_head->sha1), remote);
+               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")) {
-               const char **argv;
-               int argc;
-               char *buf;
-
-               buf = xstrdup(v);
-               argc = split_cmdline(buf, &argv);
-               if (argc < 0)
-                       die("Bad branch.%s.mergeoptions string", branch);
-               argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
-               memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
-               argc++;
-               parse_options(argc, argv, NULL, builtin_merge_options,
-                             builtin_merge_usage, 0);
-               free(buf);
+               free(branch_mergeoptions);
+               branch_mergeoptions = xstrdup(v);
+               return 0;
        }
 
        if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
@@ -501,8 +556,24 @@ static int git_merge_config(const char *k, const char *v, void *cb)
                return git_config_string(&pull_twohead, k, v);
        else if (!strcmp(k, "pull.octopus"))
                return git_config_string(&pull_octopus, k, v);
-       else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
-               option_log = git_config_bool(k, v);
+       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;
        return git_diff_ui_config(k, v, cb);
 }
 
@@ -545,16 +616,65 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
 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");
+               die(_("git write-tree failed to write a tree"));
 }
 
-static int try_merge_strategy(const char *strategy, struct commit_list *common,
-                             const char *head_arg)
+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 *head, const char *head_arg)
+{
        int index_fd;
        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 
@@ -563,19 +683,20 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
        if (active_cache_changed &&
                        (write_cache(index_fd, active_cache, active_nr) ||
                         commit_locked_index(lock)))
-               return error("Unable to write index.");
+               return error(_("Unable to write index."));
        rollback_lock_file(lock);
 
        if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
-               int clean;
+               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.");
+                       error(_("Not handling anything other than two heads merge."));
                        return 2;
                }
 
@@ -583,68 +704,32 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                if (!strcmp(strategy, "subtree"))
                        o.subtree_shift = "";
 
-               for (x = 0; x < xopts_nr; x++) {
-                       if (!strcmp(xopts[x], "ours"))
-                               o.recursive_variant = MERGE_RECURSIVE_OURS;
-                       else if (!strcmp(xopts[x], "theirs"))
-                               o.recursive_variant = MERGE_RECURSIVE_THEIRS;
-                       else if (!strcmp(xopts[x], "subtree"))
-                               o.subtree_shift = "";
-                       else if (!prefixcmp(xopts[x], "subtree="))
-                               o.subtree_shift = xopts[x]+8;
-                       else
-                               die("Unknown option for merge-recursive: -X%s", xopts[x]);
-               }
+               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 = remoteheads->item->util;
+               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, lookup_commit(head),
+               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());
+                       die (_("unable to write %s"), get_index_file());
                rollback_lock_file(lock);
                return clean ? 0 : 1;
        } else {
-               args = xmalloc((4 + xopts_nr + commit_list_count(common) +
-                                       commit_list_count(remoteheads)) * 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(sha1_to_hex(j->item->object.sha1));
-               args[i++] = "--";
-               args[i++] = head_arg;
-               for (j = remoteheads; j; j = j->next)
-                       args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
-               args[i] = NULL;
-               ret = run_command_v_opt(args, RUN_GIT_CMD);
-               strbuf_release(&buf);
-               i = 1;
-               for (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 = remoteheads; 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;
+               return try_merge_command(strategy, xopts_nr, xopts,
+                                               common, head_arg, remoteheads);
        }
 }
 
@@ -667,7 +752,7 @@ static int count_unmerged_entries(void)
        return ret;
 }
 
-static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
+int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
 {
        struct tree *trees[MAX_UNPACK_TREES];
        struct unpack_trees_options opts;
@@ -683,10 +768,12 @@ static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
        memset(&trees, 0, sizeof(trees));
        memset(&opts, 0, sizeof(opts));
        memset(&t, 0, sizeof(t));
-       memset(&dir, 0, sizeof(dir));
-       dir.flags |= DIR_SHOW_IGNORED;
-       dir.exclude_per_dir = ".gitignore";
-       opts.dir = &dir;
+       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;
@@ -695,7 +782,7 @@ static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
        opts.verbose_update = 1;
        opts.merge = 1;
        opts.fn = twoway_merge;
-       opts.msgs = get_porcelain_error_msgs();
+       setup_unpack_trees_porcelain(&opts, "merge");
 
        trees[nr_trees] = parse_tree_indirect(head);
        if (!trees[nr_trees++])
@@ -711,7 +798,7 @@ static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
                return -1;
        if (write_cache(fd, active_cache, active_nr) ||
                commit_locked_index(lock_file))
-               die("unable to write new index file");
+               die(_("unable to write new index file"));
        return 0;
 }
 
@@ -759,24 +846,79 @@ static void add_strategies(const char *string, unsigned attr)
 
 }
 
-static int merge_trivial(void)
+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(void);
+static void abort_commit(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();
+       exit(1);
+}
+
+static void prepare_to_commit(void)
+{
+       struct strbuf msg = STRBUF_INIT;
+       strbuf_addbuf(&msg, &merge_msg);
+       strbuf_addch(&msg, '\n');
+       write_merge_msg(&msg);
+       run_hook(get_index_file(), "prepare-commit-msg",
+                git_path("MERGE_MSG"), "merge", NULL, NULL);
+       if (option_edit) {
+               if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
+                       abort_commit(NULL);
+       }
+       read_merge_msg(&msg);
+       stripspace(&msg, option_edit);
+       if (!msg.len)
+               abort_commit(_("Empty commit message."));
+       strbuf_release(&merge_msg);
+       strbuf_addbuf(&merge_msg, &msg);
+       strbuf_release(&msg);
+}
+
+static int merge_trivial(struct commit *head)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parent = xmalloc(sizeof(*parent));
 
        write_tree_trivial(result_tree);
-       printf("Wonderful.\n");
-       parent->item = lookup_commit(head);
+       printf(_("Wonderful.\n"));
+       parent->item = head;
        parent->next = xmalloc(sizeof(*parent->next));
        parent->next->item = remoteheads->item;
        parent->next->next = NULL;
-       commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
-       finish(result_commit, "In-index merge");
+       prepare_to_commit();
+       if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL))
+               die(_("failed to write commit object"));
+       finish(head, result_commit, "In-index merge");
        drop_save();
        return 0;
 }
 
-static int finish_automerge(struct commit_list *common,
+static int finish_automerge(struct commit *head,
+                           struct commit_list *common,
                            unsigned char *result_tree,
                            const char *wt_strategy)
 {
@@ -787,35 +929,38 @@ static int finish_automerge(struct commit_list *common,
        free_commit_list(common);
        if (allow_fast_forward) {
                parents = remoteheads;
-               commit_list_insert(lookup_commit(head), &parents);
+               commit_list_insert(head, &parents);
                parents = reduce_heads(parents);
        } else {
                struct commit_list **pptr = &parents;
 
-               pptr = &commit_list_insert(lookup_commit(head),
+               pptr = &commit_list_insert(head,
                                pptr)->next;
                for (j = remoteheads; j; j = j->next)
                        pptr = &commit_list_insert(j->item, pptr)->next;
        }
-       free_commit_list(remoteheads);
        strbuf_addch(&merge_msg, '\n');
-       commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
-       strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
-       finish(result_commit, buf.buf);
+       prepare_to_commit();
+       free_commit_list(remoteheads);
+       if (commit_tree(&merge_msg, result_tree, parents, result_commit, NULL))
+               die(_("failed to write commit object"));
+       strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
+       finish(head, result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
 }
 
-static int suggest_conflicts(void)
+static int suggest_conflicts(int renormalizing)
 {
+       const char *filename;
        FILE *fp;
        int pos;
 
-       fp = fopen(git_path("MERGE_MSG"), "a");
+       filename = git_path("MERGE_MSG");
+       fp = fopen(filename, "a");
        if (!fp)
-               die_errno("Could not open '%s' for writing",
-                         git_path("MERGE_MSG"));
+               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];
@@ -830,12 +975,13 @@ static int suggest_conflicts(void)
        }
        fclose(fp);
        rerere(allow_rerere_auto);
-       printf("Automatic merge failed; "
-                       "fix conflicts and then commit the result.\n");
+       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)
+static struct commit *is_old_style_invocation(int argc, const char **argv,
+                                             const unsigned char *head)
 {
        struct commit *second_token = NULL;
        if (argc > 2) {
@@ -845,7 +991,7 @@ static struct commit *is_old_style_invocation(int argc, const char **argv)
                        return NULL;
                second_token = lookup_commit_reference_gently(second_sha1, 0);
                if (!second_token)
-                       die("'%s' is not a commit", argv[1]);
+                       die(_("'%s' is not a commit"), argv[1]);
                if (hashcmp(second_token->object.sha1, head))
                        return NULL;
        }
@@ -875,63 +1021,172 @@ static int evaluate_result(void)
        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(void)
+{
+       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);
+}
+
 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, head_invalid = 0, i;
+       int flag, i, ret = 0;
        int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
        struct commit_list *common = NULL;
        const char *best_strategy = NULL, *wt_strategy = NULL;
        struct commit_list **remotes = &remoteheads;
+       void *branch_to_free;
 
-       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 (argc == 2 && !strcmp(argv[1], "-h"))
+               usage_with_options(builtin_merge_usage, builtin_merge_options);
 
-       resolve_undo_clear();
        /*
         * Check if we are _not_ on a detached HEAD, i.e. if there is a
         * current branch.
         */
-       branch = resolve_ref("HEAD", head, 0, &flag);
+       branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
        if (branch && !prefixcmp(branch, "refs/heads/"))
                branch += 11;
-       if (is_null_sha1(head))
-               head_invalid = 1;
+       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);
 
-       /* for color.ui */
-       if (diff_use_color_default == -1)
-               diff_use_color_default = git_use_color_default;
-
+       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.");
+                       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.");
+               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);
@@ -945,57 +1200,61 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * additional safety measure to check for it.
         */
 
-       if (!have_message && is_old_style_invocation(argc, argv)) {
+       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;
-       } else if (head_invalid) {
-               struct object *remote_head;
+       } 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");
+                       die(_("Can merge only exactly one commit into "
+                               "empty head"));
                if (squash)
-                       die("Squash commit into empty head not supported yet");
+                       die(_("Squash commit into empty head not supported yet"));
                if (!allow_fast_forward)
-                       die("Non-fast-forward commit does not make sense into "
-                           "an empty head");
-               remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
+                       die(_("Non-fast-forward commit does not make sense into "
+                           "an empty head"));
+               remote_head = get_merge_parent(argv[0]);
                if (!remote_head)
-                       die("%s - not something we can merge", argv[0]);
-               update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
-                               DIE_ON_ERR);
-               reset_hard(remote_head->sha1, 0);
-               return 0;
+                       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 msg = STRBUF_INIT;
+               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.  If remote
-                * is invalid we will die later in the common
-                * codepath so we discard the error in this
-                * loop.
+                * All the rest are the commits being merged; prepare
+                * the standard merge summary message to be appended
+                * to the given message.
                 */
-               if (!have_message) {
-                       for (i = 0; i < argc; i++)
-                               merge_name(argv[i], &msg);
-                       fmt_merge_msg(option_log, &msg, &merge_msg);
+               for (i = 0; i < argc; i++)
+                       merge_name(argv[i], &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);
+                               strbuf_setlen(&merge_msg, merge_msg.len - 1);
                }
        }
 
-       if (head_invalid || !argc)
+       if (!head_commit || !argc)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
 
@@ -1006,19 +1265,20 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        strbuf_reset(&buf);
 
        for (i = 0; i < argc; i++) {
-               struct object *o;
-               struct commit *commit;
-
-               o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
-               if (!o)
-                       die("%s - not something we can merge", argv[i]);
-               commit = lookup_commit(o->sha1);
-               commit->util = (void *)argv[i];
+               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;
-
-               strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
+               strbuf_addf(&buf, "GITHEAD_%s",
+                           sha1_to_hex(commit->object.sha1));
                setenv(buf.buf, argv[i], 1);
                strbuf_reset(&buf);
+               if (merge_remote_util(commit) &&
+                   merge_remote_util(commit)->obj &&
+                   merge_remote_util(commit)->obj->type == OBJ_TAG) {
+                       option_edit = 1;
+                       allow_fast_forward = 0;
+               }
        }
 
        if (!use_strategies) {
@@ -1036,17 +1296,16 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        }
 
        if (!remoteheads->next)
-               common = get_merge_bases(lookup_commit(head),
-                               remoteheads->item, 1);
+               common = get_merge_bases(head_commit, remoteheads->item, 1);
        else {
                struct commit_list *list = remoteheads;
-               commit_list_insert(lookup_commit(head), &list);
+               commit_list_insert(head_commit, &list);
                common = get_octopus_merge_bases(list);
                free(list);
        }
 
-       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
-               DIE_ON_ERR);
+       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
+                  NULL, 0, DIE_ON_ERR);
 
        if (!common)
                ; /* No common ancestors found. We need a real merge. */
@@ -1057,19 +1316,19 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                 * but first the most common case of merging one remote.
                 */
                finish_up_to_date("Already up-to-date.");
-               return 0;
+               goto done;
        } else if (allow_fast_forward && !remoteheads->next &&
                        !common->next &&
-                       !hashcmp(common->item->object.sha1, head)) {
+                       !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
                /* Again the most common case of merging one remote. */
                struct strbuf msg = STRBUF_INIT;
-               struct object *o;
+               struct commit *commit;
                char hex[41];
 
-               strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
+               strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
 
                if (verbosity >= 0)
-                       printf("Updating %s..%s\n",
+                       printf(_("Updating %s..%s\n"),
                                hex,
                                find_unique_abbrev(remoteheads->item->object.sha1,
                                DEFAULT_ABBREV));
@@ -1077,17 +1336,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (have_message)
                        strbuf_addstr(&msg,
                                " (no commit created; -m option ignored)");
-               o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
-                       0, NULL, OBJ_COMMIT);
-               if (!o)
-                       return 1;
+               commit = remoteheads->item;
+               if (!commit) {
+                       ret = 1;
+                       goto done;
+               }
 
-               if (checkout_fast_forward(head, remoteheads->item->object.sha1))
-                       return 1;
+               if (checkout_fast_forward(head_commit->object.sha1,
+                                         commit->object.sha1)) {
+                       ret = 1;
+                       goto done;
+               }
 
-               finish(o->sha1, msg.buf);
+               finish(head_commit, commit->object.sha1, msg.buf);
                drop_save();
-               return 0;
+               goto done;
        } else if (!remoteheads->next && common->next)
                ;
                /*
@@ -1103,11 +1366,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                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");
+                       printf(_("Trying really trivial in-index merge...\n"));
                        if (!read_tree_trivial(common->item->object.sha1,
-                                       head, remoteheads->item->object.sha1))
-                               return merge_trivial();
-                       printf("Nope.\n");
+                                              head_commit->object.sha1,
+                                              remoteheads->item->object.sha1)) {
+                               ret = merge_trivial(head_commit);
+                               goto done;
+                       }
+                       printf(_("Nope.\n"));
                }
        } else {
                /*
@@ -1125,8 +1391,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                         * merge_bases again, otherwise "git merge HEAD^
                         * HEAD^^" would be missed.
                         */
-                       common_one = get_merge_bases(lookup_commit(head),
-                               j->item, 1);
+                       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;
@@ -1135,12 +1400,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                }
                if (up_to_date) {
                        finish_up_to_date("Already up-to-date. Yeeah!");
-                       return 0;
+                       goto done;
                }
        }
 
        if (fast_forward_only)
-               die("Not possible to fast-forward, aborting.");
+               die(_("Not possible to fast-forward, aborting."));
 
        /* We are going to make a new commit. */
        git_committer_info(IDENT_ERROR_ON_NO_NAME);
@@ -1153,24 +1418,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * sync with the head commit.  The strategies are responsible
         * to ensure this.
         */
-       if (use_strategies_nr != 1) {
-               /*
-                * Stash away the local changes so that we can try more
-                * than one.
-                */
-               save_state();
-       } else {
-               memcpy(stash, null_sha1, 20);
-       }
+       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();
+                       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",
+                       printf(_("Trying merge strategy %s...\n"),
                                use_strategies[i]->name);
                /*
                 * Remember which strategy left the state in the working
@@ -1179,7 +1441,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                wt_strategy = use_strategies[i]->name;
 
                ret = try_merge_strategy(use_strategies[i]->name,
-                       common, head_arg);
+                                        common, head_commit, head_arg);
                if (!option_commit && !ret) {
                        merge_was_ok = 1;
                        /*
@@ -1220,73 +1482,48 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * If we have a resulting tree, that means the strategy module
         * auto resolved the merge cleanly.
         */
-       if (automerge_was_ok)
-               return finish_automerge(common, result_tree, wt_strategy);
+       if (automerge_was_ok) {
+               ret = finish_automerge(head_commit, common, 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();
+               restore_state(head_commit->object.sha1, stash);
                if (use_strategies_nr > 1)
                        fprintf(stderr,
-                               "No merge strategy handled the merge.\n");
+                               _("No merge strategy handled the merge.\n"));
                else
-                       fprintf(stderr, "Merge with strategy %s failed.\n",
+                       fprintf(stderr, _("Merge with strategy %s failed.\n"),
                                use_strategies[0]->name);
-               return 2;
+               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();
-               printf("Using the %s to prepare resolving by hand.\n",
+               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, head_arg);
+               try_merge_strategy(best_strategy, common, head_commit, head_arg);
        }
 
        if (squash)
-               finish(NULL, NULL);
-       else {
-               int fd;
-               struct commit_list *j;
-
-               for (j = remoteheads; j; j = j->next)
-                       strbuf_addf(&buf, "%s\n",
-                               sha1_to_hex(j->item->object.sha1));
-               fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
-               if (fd < 0)
-                       die_errno("Could not open '%s' for writing",
-                                 git_path("MERGE_HEAD"));
-               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-                       die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
-               close(fd);
-               strbuf_addch(&merge_msg, '\n');
-               fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
-               if (fd < 0)
-                       die_errno("Could not open '%s' for writing",
-                                 git_path("MERGE_MSG"));
-               if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
-                       merge_msg.len)
-                       die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
-               close(fd);
-               fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
-               if (fd < 0)
-                       die_errno("Could not open '%s' for writing",
-                                 git_path("MERGE_MODE"));
-               strbuf_reset(&buf);
-               if (!allow_fast_forward)
-                       strbuf_addf(&buf, "no-ff");
-               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-                       die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
-               close(fd);
-       }
-
-       if (merge_was_ok) {
-               fprintf(stderr, "Automatic merge went well; "
-                       "stopped before committing as requested\n");
-               return 0;
-       } else
-               return suggest_conflicts();
+               finish(head_commit, NULL, NULL);
+       else
+               write_merge_state();
+
+       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;
 }