system_path: move RUNTIME_PREFIX to a sub-function
[gitweb.git] / builtin / merge.c
index 85c54dcd5a21f2b8413e5f73585f5f0a6c4c5715..848a29855611d22bf19f3740a577a2b312294257 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)
@@ -45,6 +46,7 @@ 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 +66,8 @@ 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 +214,7 @@ 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 +225,10 @@ 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) "" },
@@ -231,9 +239,9 @@ static struct option builtin_merge_options[] = {
 /* Cleans up metadata that is uninteresting after a succeeded merge. */
 static void drop_save(void)
 {
-       unlink(git_path("MERGE_HEAD"));
-       unlink(git_path("MERGE_MSG"));
-       unlink(git_path("MERGE_MODE"));
+       unlink(git_path_merge_head());
+       unlink(git_path_merge_msg());
+       unlink(git_path_merge_mode());
 }
 
 static int save_state(unsigned char *stash)
@@ -333,15 +341,9 @@ 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;
@@ -365,13 +367,10 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
        while ((commit = get_revision(&rev)) != NULL) {
                strbuf_addch(&out, '\n');
                strbuf_addf(&out, "commit %s\n",
-                       sha1_to_hex(commit->object.sha1));
+                       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);
 }
 
@@ -380,7 +379,7 @@ 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;
+       const unsigned char *head = head_commit->object.oid.hash;
 
        if (!msg)
                strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -404,6 +403,7 @@ static void finish(struct commit *head_commit,
                         * We ignore errors in 'gc --auto', since the
                         * user should see them.
                         */
+                       close_all_packs();
                        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
                }
        }
@@ -438,7 +438,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        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));
@@ -497,7 +497,7 @@ 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.sha1),
+                                   oid_to_hex(&remote_head->object.oid),
                                    truname.buf + 11,
                                    (early ? " (early part)" : ""));
                        strbuf_release(&truname);
@@ -511,7 +511,7 @@ 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->sha1),
+                                   oid_to_hex(&desc->obj->oid),
                                    typename(desc->obj->type),
                                    remote);
                        goto cleanup;
@@ -519,7 +519,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        }
 
        strbuf_addf(msg, "%s\t\tcommit '%s'\n",
-               sha1_to_hex(remote_head->object.sha1), remote);
+               oid_to_hex(&remote_head->object.oid), remote);
 cleanup:
        strbuf_release(&buf);
        strbuf_release(&bname);
@@ -638,7 +638,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 {
        static struct lock_file lock;
 
-       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))
@@ -675,9 +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());
@@ -708,42 +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++)
@@ -752,21 +729,9 @@ 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");
+       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);
@@ -797,16 +762,16 @@ 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))
+                           git_path_merge_msg(), "merge", NULL))
                abort_commit(remoteheads, NULL);
        if (0 < option_edit) {
-               if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
+               if (launch_editor(git_path_merge_msg(), NULL, NULL))
                        abort_commit(remoteheads, NULL);
        }
        read_merge_msg(&msg);
-       stripspace(&msg, 0 < option_edit);
+       strbuf_stripspace(&msg, 0 < option_edit);
        if (!msg.len)
                abort_commit(remoteheads, _("Empty commit message."));
        strbuf_release(&merge_msg);
@@ -818,6 +783,14 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parents, **pptr = &parents;
+       static struct lock_file lock;
+
+       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"));
@@ -865,7 +838,7 @@ static int suggest_conflicts(void)
        FILE *fp;
        struct strbuf msgbuf = STRBUF_INIT;
 
-       filename = git_path("MERGE_MSG");
+       filename = git_path_merge_msg();
        fp = fopen(filename, "a");
        if (!fp)
                die_errno(_("Could not open '%s' for writing"), filename);
@@ -892,7 +865,7 @@ static struct commit *is_old_style_invocation(int argc, const char **argv,
                second_token = lookup_commit_reference_gently(second_sha1, 0);
                if (!second_token)
                        die(_("'%s' is not a commit"), argv[1]);
-               if (hashcmp(second_token->object.sha1, head))
+               if (hashcmp(second_token->object.oid.hash, head))
                        return NULL;
        }
        return second_token;
@@ -938,7 +911,7 @@ static int setup_with_upstream(const char ***argv)
        if (!branch->merge_nr)
                die(_("No default upstream defined for the current branch."));
 
-       args = xcalloc(branch->merge_nr + 1, sizeof(char *));
+       args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
        for (i = 0; i < branch->merge_nr; i++) {
                if (!branch->merge[i]->dst)
                        die(_("No remote-tracking branch for %s from %s"),
@@ -952,41 +925,27 @@ 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;
 
        for (j = remoteheads; j; j = j->next) {
-               unsigned const char *sha1;
+               struct object_id *oid;
                struct commit *c = j->item;
                if (c->util && merge_remote_util(c)->obj) {
-                       sha1 = merge_remote_util(c)->obj->sha1;
+                       oid = &merge_remote_util(c)->obj->oid;
                } else {
-                       sha1 = c->object.sha1;
+                       oid = &c->object.oid;
                }
-               strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
+               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)
@@ -1002,7 +961,7 @@ 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;
        }
 
@@ -1019,7 +978,7 @@ static struct commit_list *reduce_parents(struct commit *head_commit,
                                          int *head_subsumed,
                                          struct commit_list *remoteheads)
 {
-       struct commit_list *parents, *next, **remotes = &remoteheads;
+       struct commit_list *parents, **remotes;
 
        /*
         * Is the current HEAD reachable from another commit being
@@ -1033,16 +992,14 @@ static struct commit_list *reduce_parents(struct commit *head_commit,
        /* Find what parents to record by checking independent ones. */
        parents = reduce_heads(remoteheads);
 
-       for (remoteheads = NULL, remotes = &remoteheads;
-            parents;
-            parents = next) {
-               struct commit *commit = parents->item;
-               next = parents->next;
+       remoteheads = NULL;
+       remotes = &remoteheads;
+       while (parents) {
+               struct commit *commit = pop_commit(&parents);
                if (commit == head_commit)
                        *head_subsumed = 0;
                else
                        remotes = &commit_list_insert(commit, remotes)->next;
-               free(parents);
        }
        return remoteheads;
 }
@@ -1070,7 +1027,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
        if (!merge_names)
                merge_names = &fetch_head_file;
 
-       filename = git_path("FETCH_HEAD");
+       filename = git_path_fetch_head();
        fd = open(filename, O_RDONLY);
        if (fd < 0)
                die_errno(_("could not open '%s' for reading"), filename);
@@ -1105,7 +1062,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
                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;
@@ -1139,7 +1096,7 @@ 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);
@@ -1166,12 +1123,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        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);
@@ -1180,7 +1138,7 @@ 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_sha1, NULL);
        if (branch && starts_with(branch, "refs/heads/"))
                branch += 11;
        if (!branch || is_null_sha1(head_sha1))
@@ -1188,6 +1146,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        else
                head_commit = lookup_commit_or_die(head_sha1, "HEAD");
 
+       init_diff_ui_defaults();
        git_config(git_merge_config, NULL);
 
        if (branch_mergeoptions)
@@ -1204,7 +1163,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                int nargc = 2;
                const char *nargv[] = {"reset", "--merge", NULL};
 
-               if (!file_exists(git_path("MERGE_HEAD")))
+               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)."));
 
                /* Invoke 'git reset --merge' */
@@ -1212,10 +1175,26 @@ 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");
 
-       if (file_exists(git_path("MERGE_HEAD"))) {
+       if (file_exists(git_path_merge_head())) {
                /*
                 * There is no unmerged entry, don't advise 'git
                 * add/rm <file>', just 'git commit'.
@@ -1226,7 +1205,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                else
                        die(_("You have not concluded your merge (MERGE_HEAD exists)."));
        }
-       if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+       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 merge."));
@@ -1258,12 +1237,12 @@ 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".
                 */
+               unsigned char *remote_head_sha1;
                if (squash)
                        die(_("Squash commit into empty head not supported yet"));
                if (fast_forward == FF_NO)
@@ -1271,13 +1250,13 @@ 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.sha1, 0);
-               update_ref("initial pull", "HEAD", remote_head->object.sha1,
+               remote_head_sha1 = remoteheads->item->object.oid.hash;
+               read_empty(remote_head_sha1, 0);
+               update_ref("initial pull", "HEAD", remote_head_sha1,
                           NULL, 0, UPDATE_REFS_DIE_ON_ERR);
                goto done;
        }
@@ -1291,7 +1270,7 @@ 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, head_commit->object.sha1)) {
+           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];
@@ -1319,13 +1298,13 @@ 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[41];
+                       char hex[GIT_SHA1_HEXSZ + 1];
                        struct signature_check signature_check;
                        memset(&signature_check, 0, sizeof(signature_check));
 
                        check_commit_signature(commit, &signature_check);
 
-                       strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+                       find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
                        switch (signature_check.result) {
                        case 'G':
                                break;
@@ -1355,7 +1334,7 @@ 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.sha1));
+                           oid_to_hex(&commit->object.oid));
                setenv(buf.buf, merge_remote_util(commit)->name, 1);
                strbuf_reset(&buf);
                if (fast_forward != FF_ONLY &&
@@ -1395,35 +1374,37 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                free(list);
        }
 
-       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
+       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.sha1, head_commit->object.sha1)) {
+                       !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;
-               char hex[41];
-
-               strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
 
-               if (verbosity >= 0)
+               if (verbosity >= 0) {
                        printf(_("Updating %s..%s\n"),
-                               hex,
-                               find_unique_abbrev(remoteheads->item->object.sha1,
-                               DEFAULT_ABBREV));
+                              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)
                        strbuf_addstr(&msg,
@@ -1434,14 +1415,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        goto done;
                }
 
-               if (checkout_fast_forward(head_commit->object.sha1,
-                                         commit->object.sha1,
+               if (checkout_fast_forward(head_commit->object.oid.hash,
+                                         commit->object.oid.hash,
                                          overwrite_ignore)) {
                        ret = 1;
                        goto done;
                }
 
-               finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
+               finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
                drop_save();
                goto done;
        } else if (!remoteheads->next && common->next)
@@ -1460,9 +1441,9 @@ 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.sha1,
-                                              head_commit->object.sha1,
-                                              remoteheads->item->object.sha1)) {
+                       if (!read_tree_trivial(common->item->object.oid.hash,
+                                              head_commit->object.oid.hash,
+                                              remoteheads->item->object.oid.hash)) {
                                ret = merge_trivial(head_commit, remoteheads);
                                goto done;
                        }
@@ -1485,14 +1466,13 @@ 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.sha1,
-                               j->item->object.sha1)) {
+                       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;
                }
        }
@@ -1516,13 +1496,13 @@ 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);
+               hashclr(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.sha1, stash);
+                       restore_state(head_commit->object.oid.hash, stash);
                }
                if (use_strategies_nr != 1)
                        printf(_("Trying merge strategy %s...\n"),
@@ -1588,7 +1568,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * it up.
         */
        if (!best_strategy) {
-               restore_state(head_commit->object.sha1, stash);
+               restore_state(head_commit->object.oid.hash, stash);
                if (use_strategies_nr > 1)
                        fprintf(stderr,
                                _("No merge strategy handled the merge.\n"));
@@ -1601,7 +1581,7 @@ 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.sha1, stash);
+               restore_state(head_commit->object.oid.hash, stash);
                printf(_("Using the %s to prepare resolving by hand.\n"),
                        best_strategy);
                try_merge_strategy(best_strategy, common, remoteheads,