blame: move no_whole_file_rename flag to scoreboard
[gitweb.git] / builtin / merge.c
index 101ffeff4c942636e0ca688357a4b8ec8aa2a431..703827f00668ca0df807f35e300f0927d00075cd 100644 (file)
@@ -30,6 +30,7 @@
 #include "fmt-merge-msg.h"
 #include "gpg-interface.h"
 #include "sequencer.h"
+#include "string-list.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -43,8 +44,8 @@ struct strategy {
 
 static const char * const builtin_merge_usage[] = {
        N_("git merge [<options>] [<commit>...]"),
-       N_("git merge [<options>] <msg> HEAD <commit>"),
        N_("git merge --abort"),
+       N_("git merge --continue"),
        NULL
 };
 
@@ -64,6 +65,8 @@ static int option_renormalize;
 static int verbosity;
 static int allow_rerere_auto;
 static int abort_current_merge;
+static int continue_current_merge;
+static int allow_unrelated_histories;
 static int show_progress = -1;
 static int default_to_upstream = 1;
 static const char *sign_commit;
@@ -210,7 +213,7 @@ static struct option builtin_merge_options[] = {
                PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
        OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
        OPT_BOOL(0, "verify-signatures", &verify_signatures,
-               N_("Verify that the named commit has a valid GPG signature")),
+               N_("verify that the named commit has a valid GPG signature")),
        OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
                N_("merge strategy to use"), option_parse_strategy),
        OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
@@ -221,6 +224,10 @@ static struct option builtin_merge_options[] = {
        OPT__VERBOSITY(&verbosity),
        OPT_BOOL(0, "abort", &abort_current_merge,
                N_("abort the current in-progress merge")),
+       OPT_BOOL(0, "continue", &continue_current_merge,
+               N_("continue the current in-progress merge")),
+       OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
+                N_("allow merging unrelated histories")),
        OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
        { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
          N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
@@ -236,7 +243,7 @@ static void drop_save(void)
        unlink(git_path_merge_mode());
 }
 
-static int save_state(unsigned char *stash)
+static int save_state(struct object_id *stash)
 {
        int len;
        struct child_process cp = CHILD_PROCESS_INIT;
@@ -257,7 +264,7 @@ static int save_state(unsigned char *stash)
        else if (!len)          /* no changes */
                return -1;
        strbuf_setlen(&buffer, buffer.len-1);
-       if (get_sha1(buffer.buf, stash))
+       if (get_oid(buffer.buf, stash))
                die(_("not a valid object: %s"), buffer.buf);
        return 0;
 }
@@ -297,18 +304,18 @@ static void reset_hard(unsigned const char *sha1, int verbose)
                die(_("read-tree failed"));
 }
 
-static void restore_state(const unsigned char *head,
-                         const unsigned char *stash)
+static void restore_state(const struct object_id *head,
+                         const struct object_id *stash)
 {
        struct strbuf sb = STRBUF_INIT;
        const char *args[] = { "stash", "apply", NULL, NULL };
 
-       if (is_null_sha1(stash))
+       if (is_null_oid(stash))
                return;
 
-       reset_hard(head, 1);
+       reset_hard(head->hash, 1);
 
-       args[2] = sha1_to_hex(stash);
+       args[2] = oid_to_hex(stash);
 
        /*
         * It is OK to ignore error here, for example when there was
@@ -333,15 +340,9 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
        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;
@@ -368,19 +369,16 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
                        oid_to_hex(&commit->object.oid));
                pretty_print_commit(&ctx, commit, &out);
        }
-       if (write_in_full(fd, out.buf, out.len) != out.len)
-               die_errno(_("Writing SQUASH_MSG"));
-       if (close(fd))
-               die_errno(_("Finishing SQUASH_MSG"));
+       write_file_buf(git_path_squash_msg(), out.buf, out.len);
        strbuf_release(&out);
 }
 
 static void finish(struct commit *head_commit,
                   struct commit_list *remoteheads,
-                  const unsigned char *new_head, const char *msg)
+                  const struct object_id *new_head, const char *msg)
 {
        struct strbuf reflog_message = STRBUF_INIT;
-       const unsigned char *head = head_commit->object.oid.hash;
+       const struct object_id *head = &head_commit->object.oid;
 
        if (!msg)
                strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -398,7 +396,7 @@ static void finish(struct commit *head_commit,
                else {
                        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
                        update_ref(reflog_message.buf, "HEAD",
-                               new_head, head, 0,
+                               new_head->hash, head->hash, 0,
                                UPDATE_REFS_DIE_ON_ERR);
                        /*
                         * We ignore errors in 'gc --auto', since the
@@ -417,7 +415,7 @@ static void finish(struct commit *head_commit,
                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
                opts.detect_rename = DIFF_DETECT_RENAME;
                diff_setup_done(&opts);
-               diff_tree_sha1(head, new_head, "", &opts);
+               diff_tree_sha1(head->hash, new_head->hash, "", &opts);
                diffcore_std(&opts);
                diff_flush(&opts);
        }
@@ -432,35 +430,35 @@ static void finish(struct commit *head_commit,
 static void merge_name(const char *remote, struct strbuf *msg)
 {
        struct commit *remote_head;
-       unsigned char branch_head[20];
+       struct object_id branch_head;
        struct strbuf buf = STRBUF_INIT;
        struct strbuf bname = STRBUF_INIT;
        const char *ptr;
        char *found_ref;
        int len, early;
 
-       strbuf_branchname(&bname, remote);
+       strbuf_branchname(&bname, remote, 0);
        remote = bname.buf;
 
-       memset(branch_head, 0, sizeof(branch_head));
+       oidclr(&branch_head);
        remote_head = get_merge_parent(remote);
        if (!remote_head)
                die(_("'%s' does not point to a commit"), remote);
 
-       if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
+       if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
                if (starts_with(found_ref, "refs/heads/")) {
                        strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
-                                   sha1_to_hex(branch_head), remote);
+                                   oid_to_hex(&branch_head), remote);
                        goto cleanup;
                }
                if (starts_with(found_ref, "refs/tags/")) {
                        strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
-                                   sha1_to_hex(branch_head), remote);
+                                   oid_to_hex(&branch_head), remote);
                        goto cleanup;
                }
                if (starts_with(found_ref, "refs/remotes/")) {
                        strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
-                                   sha1_to_hex(branch_head), remote);
+                                   oid_to_hex(&branch_head), remote);
                        goto cleanup;
                }
        }
@@ -498,7 +496,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
                if (ref_exists(truname.buf)) {
                        strbuf_addf(msg,
                                    "%s\t\tbranch '%s'%s of .\n",
-                                   sha1_to_hex(remote_head->object.oid.hash),
+                                   oid_to_hex(&remote_head->object.oid),
                                    truname.buf + 11,
                                    (early ? " (early part)" : ""));
                        strbuf_release(&truname);
@@ -512,7 +510,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
                desc = merge_remote_util(remote_head);
                if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
                        strbuf_addf(msg, "%s\t\t%s '%s'\n",
-                                   sha1_to_hex(desc->obj->oid.hash),
+                                   oid_to_hex(&desc->obj->oid),
                                    typename(desc->obj->type),
                                    remote);
                        goto cleanup;
@@ -520,7 +518,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        }
 
        strbuf_addf(msg, "%s\t\tcommit '%s'\n",
-               sha1_to_hex(remote_head->object.oid.hash), remote);
+               oid_to_hex(&remote_head->object.oid), remote);
 cleanup:
        strbuf_release(&buf);
        strbuf_release(&bname);
@@ -591,8 +589,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
        return git_diff_ui_config(k, v, cb);
 }
 
-static int read_tree_trivial(unsigned char *common, unsigned char *head,
-                            unsigned char *one)
+static int read_tree_trivial(struct object_id *common, struct object_id *head,
+                            struct object_id *one)
 {
        int i, nr_trees = 0;
        struct tree *trees[MAX_UNPACK_TREES];
@@ -607,13 +605,13 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
        opts.verbose_update = 1;
        opts.trivial_merges_only = 1;
        opts.merge = 1;
-       trees[nr_trees] = parse_tree_indirect(common);
+       trees[nr_trees] = parse_tree_indirect(common->hash);
        if (!trees[nr_trees++])
                return -1;
-       trees[nr_trees] = parse_tree_indirect(head);
+       trees[nr_trees] = parse_tree_indirect(head->hash);
        if (!trees[nr_trees++])
                return -1;
-       trees[nr_trees] = parse_tree_indirect(one);
+       trees[nr_trees] = parse_tree_indirect(one->hash);
        if (!trees[nr_trees++])
                return -1;
        opts.fn = threeway_merge;
@@ -627,19 +625,20 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
        return 0;
 }
 
-static void write_tree_trivial(unsigned char *sha1)
+static void write_tree_trivial(struct object_id *oid)
 {
-       if (write_cache_as_tree(sha1, 0, NULL))
+       if (write_cache_as_tree(oid->hash, 0, NULL))
                die(_("git write-tree failed to write a tree"));
 }
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
                              struct commit_list *remoteheads,
-                             struct commit *head, const char *head_arg)
+                             struct commit *head)
 {
        static struct lock_file lock;
+       const char *head_arg = "HEAD";
 
-       hold_locked_index(&lock, 1);
+       hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
        refresh_cache(REFRESH_QUIET);
        if (active_cache_changed &&
            write_locked_index(&the_index, &lock, COMMIT_LOCK))
@@ -676,9 +675,11 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                for (j = common; j; j = j->next)
                        commit_list_insert(j->item, &reversed);
 
-               hold_locked_index(&lock, 1);
+               hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
                clean = merge_recursive(&o, head,
                                remoteheads->item, reversed, &result);
+               if (clean < 0)
+                       exit(128);
                if (active_cache_changed &&
                    write_locked_index(&the_index, &lock, COMMIT_LOCK))
                        die (_("unable to write %s"), get_index_file());
@@ -709,42 +710,17 @@ static int count_unmerged_entries(void)
        return ret;
 }
 
-static void split_merge_strategies(const char *string, struct strategy **list,
-                                  int *nr, int *alloc)
-{
-       char *p, *q, *buf;
-
-       if (!string)
-               return;
-
-       buf = xstrdup(string);
-       q = buf;
-       for (;;) {
-               p = strchr(q, ' ');
-               if (!p) {
-                       ALLOC_GROW(*list, *nr + 1, *alloc);
-                       (*list)[(*nr)++].name = xstrdup(q);
-                       free(buf);
-                       return;
-               } else {
-                       *p = '\0';
-                       ALLOC_GROW(*list, *nr + 1, *alloc);
-                       (*list)[(*nr)++].name = xstrdup(q);
-                       q = ++p;
-               }
-       }
-}
-
 static void add_strategies(const char *string, unsigned attr)
 {
-       struct strategy *list = NULL;
-       int list_alloc = 0, list_nr = 0, i;
-
-       memset(&list, 0, sizeof(list));
-       split_merge_strategies(string, &list, &list_nr, &list_alloc);
-       if (list) {
-               for (i = 0; i < list_nr; i++)
-                       append_strategy(get_strategy(list[i].name));
+       int i;
+
+       if (string) {
+               struct string_list list = STRING_LIST_INIT_DUP;
+               struct string_list_item *item;
+               string_list_split(&list, string, ' ', -1);
+               for_each_string_list_item(item, &list)
+                       append_strategy(get_strategy(item->string));
+               string_list_clear(&list, 0);
                return;
        }
        for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
@@ -753,18 +729,6 @@ static void add_strategies(const char *string, unsigned attr)
 
 }
 
-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();
@@ -798,7 +762,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
        strbuf_addch(&msg, '\n');
        if (0 < option_edit)
                strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
-       write_merge_msg(&msg);
+       write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
        if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
                            git_path_merge_msg(), "merge", NULL))
                abort_commit(remoteheads, NULL);
@@ -817,18 +781,26 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 
 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
-       unsigned char result_tree[20], result_commit[20];
+       struct object_id result_tree, result_commit;
        struct commit_list *parents, **pptr = &parents;
+       static struct lock_file lock;
 
-       write_tree_trivial(result_tree);
+       hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
+       refresh_cache(REFRESH_QUIET);
+       if (active_cache_changed &&
+           write_locked_index(&the_index, &lock, COMMIT_LOCK))
+               return error(_("Unable to write index."));
+       rollback_lock_file(&lock);
+
+       write_tree_trivial(&result_tree);
        printf(_("Wonderful.\n"));
        pptr = commit_list_append(head, pptr);
        pptr = commit_list_append(remoteheads->item, pptr);
        prepare_to_commit(remoteheads);
-       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
-                       result_commit, NULL, sign_commit))
+       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
+                       result_commit.hash, NULL, sign_commit))
                die(_("failed to write commit object"));
-       finish(head, remoteheads, result_commit, "In-index merge");
+       finish(head, remoteheads, &result_commit, "In-index merge");
        drop_save();
        return 0;
 }
@@ -837,12 +809,12 @@ static int finish_automerge(struct commit *head,
                            int head_subsumed,
                            struct commit_list *common,
                            struct commit_list *remoteheads,
-                           unsigned char *result_tree,
+                           struct object_id *result_tree,
                            const char *wt_strategy)
 {
        struct commit_list *parents = NULL;
        struct strbuf buf = STRBUF_INIT;
-       unsigned char result_commit[20];
+       struct object_id result_commit;
 
        free_commit_list(common);
        parents = remoteheads;
@@ -850,11 +822,11 @@ static int finish_automerge(struct commit *head,
                commit_list_insert(head, &parents);
        strbuf_addch(&merge_msg, '\n');
        prepare_to_commit(remoteheads);
-       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
-                       result_commit, NULL, sign_commit))
+       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
+                       result_commit.hash, 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);
+       finish(head, remoteheads, &result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
@@ -881,24 +853,6 @@ static int suggest_conflicts(void)
        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.oid.hash, head))
-                       return NULL;
-       }
-       return second_token;
-}
-
 static int evaluate_result(void)
 {
        int cnt = 0;
@@ -953,8 +907,6 @@ static int setup_with_upstream(const char ***argv)
 
 static void write_merge_state(struct commit_list *remoteheads)
 {
-       const char *filename;
-       int fd;
        struct commit_list *j;
        struct strbuf buf = STRBUF_INIT;
 
@@ -968,26 +920,14 @@ static void write_merge_state(struct commit_list *remoteheads)
                }
                strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
        }
-       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);
+       write_file_buf(git_path_merge_head(), buf.buf, buf.len);
        strbuf_addch(&merge_msg, '\n');
-       write_merge_msg(&merge_msg);
+       write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
 
-       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 (fast_forward == FF_NO)
-               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);
+               strbuf_addstr(&buf, "no-ff");
+       write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
 }
 
 static int default_edit_option(void)
@@ -1003,7 +943,7 @@ static int default_edit_option(void)
        if (e) {
                int v = git_config_maybe_bool(name, e);
                if (v < 0)
-                       die("Bad value '%s' in environment '%s'", e, name);
+                       die(_("Bad value '%s' in environment '%s'"), e, name);
                return v;
        }
 
@@ -1080,7 +1020,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
                die_errno(_("could not close '%s'"), filename);
 
        for (pos = 0; pos < merge_names->len; pos = npos) {
-               unsigned char sha1[20];
+               struct object_id oid;
                char *ptr;
                struct commit *commit;
 
@@ -1090,21 +1030,21 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
                else
                        npos = merge_names->len;
 
-               if (npos - pos < 40 + 2 ||
-                   get_sha1_hex(merge_names->buf + pos, sha1))
+               if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
+                   get_oid_hex(merge_names->buf + pos, &oid))
                        commit = NULL; /* bad */
-               else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
+               else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
                        continue; /* not-for-merge */
                else {
-                       char saved = merge_names->buf[pos + 40];
-                       merge_names->buf[pos + 40] = '\0';
+                       char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
+                       merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
                        commit = get_merge_parent(merge_names->buf + pos);
-                       merge_names->buf[pos + 40] = saved;
+                       merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
                }
                if (!commit) {
                        if (ptr)
                                *ptr = '\0';
-                       die("not something we can merge in %s: %s",
+                       die(_("not something we can merge in %s: %s"),
                            filename, merge_names->buf + pos);
                }
                remotes = &commit_list_insert(commit, remotes)->next;
@@ -1138,7 +1078,7 @@ static struct commit_list *collect_parents(struct commit *head_commit,
                        struct commit *commit = get_merge_parent(argv[i]);
                        if (!commit)
                                help_unknown_ref(argv[i], "merge",
-                                                "not something we can merge");
+                                                _("not something we can merge"));
                        remotes = &commit_list_insert(commit, remotes)->next;
                }
                remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
@@ -1159,18 +1099,16 @@ static struct commit_list *collect_parents(struct commit *head_commit,
 
 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 object_id result_tree, stash, head_oid;
        struct commit *head_commit;
        struct strbuf buf = STRBUF_INIT;
-       const char *head_arg;
-       int flag, i, ret = 0, head_subsumed;
+       int i, ret = 0, head_subsumed;
        int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
        struct commit_list *common = NULL;
        const char *best_strategy = NULL, *wt_strategy = NULL;
        struct commit_list *remoteheads, *p;
        void *branch_to_free;
+       int orig_argc = argc;
 
        if (argc == 2 && !strcmp(argv[1], "-h"))
                usage_with_options(builtin_merge_usage, builtin_merge_options);
@@ -1179,14 +1117,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * Check if we are _not_ on a detached HEAD, i.e. if there is a
         * current branch.
         */
-       branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, &flag);
+       branch = branch_to_free = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
        if (branch && starts_with(branch, "refs/heads/"))
                branch += 11;
-       if (!branch || is_null_sha1(head_sha1))
+       if (!branch || is_null_oid(&head_oid))
                head_commit = NULL;
        else
-               head_commit = lookup_commit_or_die(head_sha1, "HEAD");
+               head_commit = lookup_commit_or_die(head_oid.hash, "HEAD");
 
+       init_diff_ui_defaults();
        git_config(git_merge_config, NULL);
 
        if (branch_mergeoptions)
@@ -1203,6 +1142,10 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                int nargc = 2;
                const char *nargv[] = {"reset", "--merge", NULL};
 
+               if (orig_argc != 2)
+                       usage_msg_opt(_("--abort expects no arguments"),
+                             builtin_merge_usage, builtin_merge_options);
+
                if (!file_exists(git_path_merge_head()))
                        die(_("There is no merge to abort (MERGE_HEAD missing)."));
 
@@ -1211,6 +1154,22 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                goto done;
        }
 
+       if (continue_current_merge) {
+               int nargc = 1;
+               const char *nargv[] = {"commit", NULL};
+
+               if (orig_argc != 2)
+                       usage_msg_opt(_("--continue expects no arguments"),
+                             builtin_merge_usage, builtin_merge_options);
+
+               if (!file_exists(git_path_merge_head()))
+                       die(_("There is no merge in progress (MERGE_HEAD missing)."));
+
+               /* Invoke 'git commit' */
+               ret = cmd_commit(nargc, nargv, prefix);
+               goto done;
+       }
+
        if (read_cache_unmerged())
                die_resolve_conflict("merge");
 
@@ -1257,12 +1216,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        builtin_merge_options);
 
        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".
                 */
+               struct object_id *remote_head_oid;
                if (squash)
                        die(_("Squash commit into empty head not supported yet"));
                if (fast_forward == FF_NO)
@@ -1270,46 +1229,24 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                            "an empty head"));
                remoteheads = collect_parents(head_commit, &head_subsumed,
                                              argc, argv, NULL);
-               remote_head = remoteheads->item;
-               if (!remote_head)
+               if (!remoteheads)
                        die(_("%s - not something we can merge"), argv[0]);
                if (remoteheads->next)
                        die(_("Can merge only exactly one commit into empty head"));
-               read_empty(remote_head->object.oid.hash, 0);
-               update_ref("initial pull", "HEAD", remote_head->object.oid.hash,
+               remote_head_oid = &remoteheads->item->object.oid;
+               read_empty(remote_head_oid->hash, 0);
+               update_ref("initial pull", "HEAD", remote_head_oid->hash,
                           NULL, 0, UPDATE_REFS_DIE_ON_ERR);
                goto done;
        }
 
        /*
-        * 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
-        * commit-ish 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.
+        * All the rest are the commits being merged; prepare
+        * the standard merge summary message to be appended
+        * to the given message.
         */
-       if (!have_message &&
-           is_old_style_invocation(argc, argv, head_commit->object.oid.hash)) {
-               warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
-               strbuf_addstr(&merge_msg, argv[0]);
-               head_arg = argv[1];
-               argv += 2;
-               argc -= 2;
-               remoteheads = collect_parents(head_commit, &head_subsumed,
-                                             argc, argv, NULL);
-       } else {
-               /* 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, &merge_msg);
-       }
+       remoteheads = collect_parents(head_commit, &head_subsumed,
+                                     argc, argv, &merge_msg);
 
        if (!head_commit || !argc)
                usage_with_options(builtin_merge_usage,
@@ -1318,7 +1255,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        if (verify_signatures) {
                for (p = remoteheads; p; p = p->next) {
                        struct commit *commit = p->item;
-                       char hex[GIT_SHA1_HEXSZ + 1];
+                       char hex[GIT_MAX_HEXSZ + 1];
                        struct signature_check signature_check;
                        memset(&signature_check, 0, sizeof(signature_check));
 
@@ -1354,7 +1291,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        for (p = remoteheads; p; p = p->next) {
                struct commit *commit = p->item;
                strbuf_addf(&buf, "GITHEAD_%s",
-                           sha1_to_hex(commit->object.oid.hash));
+                           oid_to_hex(&commit->object.oid));
                setenv(buf.buf, merge_remote_util(commit)->name, 1);
                strbuf_reset(&buf);
                if (fast_forward != FF_ONLY &&
@@ -1397,31 +1334,33 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
                   NULL, 0, UPDATE_REFS_DIE_ON_ERR);
 
-       if (remoteheads && !common)
-               ; /* No common ancestors found. We need a real merge. */
-       else if (!remoteheads ||
+       if (remoteheads && !common) {
+               /* No common ancestors found. */
+               if (!allow_unrelated_histories)
+                       die(_("refusing to merge unrelated histories"));
+               /* otherwise, we need a real merge. */
+       } else if (!remoteheads ||
                 (!remoteheads->next && !common->next &&
                  common->item == remoteheads->item)) {
                /*
                 * If head can reach all the merge then we are up to date.
                 * but first the most common case of merging one remote.
                 */
-               finish_up_to_date("Already up-to-date.");
+               finish_up_to_date(_("Already up-to-date."));
                goto done;
        } else if (fast_forward != FF_NO && !remoteheads->next &&
                        !common->next &&
-                       !hashcmp(common->item->object.oid.hash, head_commit->object.oid.hash)) {
+                       !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
                /* Again the most common case of merging one remote. */
                struct strbuf msg = STRBUF_INIT;
                struct commit *commit;
 
                if (verbosity >= 0) {
-                       char from[GIT_SHA1_HEXSZ + 1], to[GIT_SHA1_HEXSZ + 1];
-                       find_unique_abbrev_r(from, head_commit->object.oid.hash,
-                                             DEFAULT_ABBREV);
-                       find_unique_abbrev_r(to, remoteheads->item->object.oid.hash,
-                                             DEFAULT_ABBREV);
-                       printf(_("Updating %s..%s\n"), from, to);
+                       printf(_("Updating %s..%s\n"),
+                              find_unique_abbrev(head_commit->object.oid.hash,
+                                                 DEFAULT_ABBREV),
+                              find_unique_abbrev(remoteheads->item->object.oid.hash,
+                                                 DEFAULT_ABBREV));
                }
                strbuf_addstr(&msg, "Fast-forward");
                if (have_message)
@@ -1440,7 +1379,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        goto done;
                }
 
-               finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
+               finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
                drop_save();
                goto done;
        } else if (!remoteheads->next && common->next)
@@ -1459,9 +1398,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        /* See if it is really trivial. */
                        git_committer_info(IDENT_STRICT);
                        printf(_("Trying really trivial in-index merge...\n"));
-                       if (!read_tree_trivial(common->item->object.oid.hash,
-                                              head_commit->object.oid.hash,
-                                              remoteheads->item->object.oid.hash)) {
+                       if (!read_tree_trivial(&common->item->object.oid,
+                                              &head_commit->object.oid,
+                                              &remoteheads->item->object.oid)) {
                                ret = merge_trivial(head_commit, remoteheads);
                                goto done;
                        }
@@ -1484,14 +1423,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                         * HEAD^^" would be missed.
                         */
                        common_one = get_merge_bases(head_commit, j->item);
-                       if (hashcmp(common_one->item->object.oid.hash,
-                               j->item->object.oid.hash)) {
+                       if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
                                up_to_date = 0;
                                break;
                        }
                }
                if (up_to_date) {
-                       finish_up_to_date("Already up-to-date. Yeeah!");
+                       finish_up_to_date(_("Already up-to-date. Yeeah!"));
                        goto done;
                }
        }
@@ -1514,14 +1452,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
            /*
             * Stash away the local changes so that we can try more than one.
             */
-           save_state(stash))
-               hashcpy(stash, null_sha1);
+           save_state(&stash))
+               oidclr(&stash);
 
        for (i = 0; i < use_strategies_nr; i++) {
                int ret;
                if (i) {
                        printf(_("Rewinding the tree to pristine...\n"));
-                       restore_state(head_commit->object.oid.hash, stash);
+                       restore_state(&head_commit->object.oid, &stash);
                }
                if (use_strategies_nr != 1)
                        printf(_("Trying merge strategy %s...\n"),
@@ -1534,7 +1472,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
                ret = try_merge_strategy(use_strategies[i]->name,
                                         common, remoteheads,
-                                        head_commit, head_arg);
+                                        head_commit);
                if (!option_commit && !ret) {
                        merge_was_ok = 1;
                        /*
@@ -1566,7 +1504,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                }
 
                /* Automerge succeeded. */
-               write_tree_trivial(result_tree);
+               write_tree_trivial(&result_tree);
                automerge_was_ok = 1;
                break;
        }
@@ -1578,7 +1516,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        if (automerge_was_ok) {
                ret = finish_automerge(head_commit, head_subsumed,
                                       common, remoteheads,
-                                      result_tree, wt_strategy);
+                                      &result_tree, wt_strategy);
                goto done;
        }
 
@@ -1587,7 +1525,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * it up.
         */
        if (!best_strategy) {
-               restore_state(head_commit->object.oid.hash, stash);
+               restore_state(&head_commit->object.oid, &stash);
                if (use_strategies_nr > 1)
                        fprintf(stderr,
                                _("No merge strategy handled the merge.\n"));
@@ -1600,11 +1538,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                ; /* We already have its result in the working tree. */
        else {
                printf(_("Rewinding the tree to pristine...\n"));
-               restore_state(head_commit->object.oid.hash, stash);
+               restore_state(&head_commit->object.oid, &stash);
                printf(_("Using the %s to prepare resolving by hand.\n"),
                        best_strategy);
                try_merge_strategy(best_strategy, common, remoteheads,
-                                  head_commit, head_arg);
+                                  head_commit);
        }
 
        if (squash)