include agent identifier in capability string
[gitweb.git] / builtin / merge.c
index 7d92e2064b97828ebd5209d97b1d49807149f212..dd50a0c57b4d73d03cc84afd90594a56616d4953 100644 (file)
@@ -26,6 +26,8 @@
 #include "merge-recursive.h"
 #include "resolve-undo.h"
 #include "remote.h"
+#include "fmt-merge-msg.h"
+#include "gpg-interface.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -44,12 +46,12 @@ static const char * const builtin_merge_usage[] = {
        NULL
 };
 
-static int show_diffstat = 1, shortlog_len, squash;
+static int show_diffstat = 1, shortlog_len = -1, squash;
 static int option_commit = 1, allow_fast_forward = 1;
-static int fast_forward_only, option_edit;
+static int fast_forward_only, option_edit = -1;
 static int allow_trivial = 1, have_message;
+static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
-static struct commit_list *remoteheads;
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
 static const char **xopts;
@@ -62,6 +64,7 @@ static int allow_rerere_auto;
 static int abort_current_merge;
 static int show_progress = -1;
 static int default_to_upstream;
+static const char *sign_commit;
 
 static struct strategy all_strategy[] = {
        { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
@@ -189,7 +192,7 @@ static struct option builtin_merge_options[] = {
                "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,
+       OPT_BOOL('e', "edit", &option_edit,
                "edit message before committing"),
        OPT_BOOLEAN(0, "ff", &allow_fast_forward,
                "allow fast-forward (default)"),
@@ -207,6 +210,9 @@ static struct option builtin_merge_options[] = {
        OPT_BOOLEAN(0, "abort", &abort_current_merge,
                "abort the current in-progress merge"),
        OPT_SET_INT(0, "progress", &show_progress, "force progress reporting", 1),
+       { OPTION_STRING, 'S', "gpg-sign", &sign_commit, "key id",
+         "GPG sign commit", PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
+       OPT_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, "update ignored files (default)"),
        OPT_END()
 };
 
@@ -311,7 +317,7 @@ static void finish_up_to_date(const char *msg)
        drop_save();
 }
 
-static void squash_message(struct commit *commit)
+static void squash_message(struct commit *commit, struct commit_list *remoteheads)
 {
        struct rev_info rev;
        struct strbuf out = STRBUF_INIT;
@@ -359,6 +365,7 @@ static void squash_message(struct commit *commit)
 }
 
 static void finish(struct commit *head_commit,
+                  struct commit_list *remoteheads,
                   const unsigned char *new_head, const char *msg)
 {
        struct strbuf reflog_message = STRBUF_INIT;
@@ -373,7 +380,7 @@ static void finish(struct commit *head_commit,
                        getenv("GIT_REFLOG_ACTION"), msg);
        }
        if (squash) {
-               squash_message(head_commit);
+               squash_message(head_commit, remoteheads);
        } else {
                if (verbosity >= 0 && !merge_msg.len)
                        printf(_("No merge message -- not updating HEAD\n"));
@@ -392,6 +399,8 @@ static void finish(struct commit *head_commit,
        if (new_head && show_diffstat) {
                struct diff_options opts;
                diff_setup(&opts);
+               opts.stat_width = -1; /* use full terminal width */
+               opts.stat_graph_width = -1; /* respect statGraphWidth config */
                opts.output_format |=
                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
                opts.detect_rename = DIFF_DETECT_RENAME;
@@ -408,21 +417,11 @@ static void finish(struct commit *head_commit,
        strbuf_release(&reflog_message);
 }
 
-static struct object *want_commit(const char *name)
-{
-       struct object *obj;
-       unsigned char sha1[20];
-       if (get_sha1(name, sha1))
-               return NULL;
-       obj = parse_object(sha1);
-       return peel_to_type(name, 0, obj, OBJ_COMMIT);
-}
-
 /* 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;
@@ -433,7 +432,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        remote = bname.buf;
 
        memset(branch_head, 0, sizeof(branch_head));
-       remote_head = want_commit(remote);
+       remote_head = get_merge_parent(remote);
        if (!remote_head)
                die(_("'%s' does not point to a commit"), remote);
 
@@ -443,6 +442,11 @@ 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-tracking branch '%s' of .\n",
                                    sha1_to_hex(branch_head), remote);
@@ -481,10 +485,10 @@ 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, 1, 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);
@@ -514,7 +518,7 @@ 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);
@@ -542,6 +546,8 @@ static void parse_branch_merge_options(char *bmo)
 
 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")) {
@@ -558,15 +564,7 @@ static int git_merge_config(const char *k, const char *v, void *cb)
                return git_config_string(&pull_octopus, k, v);
        else if (!strcmp(k, "merge.renormalize"))
                option_renormalize = git_config_bool(k, v);
-       else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary")) {
-               int is_bool;
-               shortlog_len = git_config_bool_or_int(k, v, &is_bool);
-               if (!is_bool && shortlog_len < 0)
-                       return error(_("%s: negative length %s"), k, v);
-               if (is_bool && shortlog_len)
-                       shortlog_len = DEFAULT_MERGE_LOG_LEN;
-               return 0;
-       } else if (!strcmp(k, "merge.ff")) {
+       else if (!strcmp(k, "merge.ff")) {
                int boolval = git_config_maybe_bool(k, v);
                if (0 <= boolval) {
                        allow_fast_forward = boolval;
@@ -579,6 +577,13 @@ static int git_merge_config(const char *k, const char *v, void *cb)
                default_to_upstream = git_config_bool(k, v);
                return 0;
        }
+
+       status = fmt_merge_msg_config(k, v, cb);
+       if (status)
+               return status;
+       status = git_gpg_config(k, v, NULL);
+       if (status)
+               return status;
        return git_diff_ui_config(k, v, cb);
 }
 
@@ -678,6 +683,7 @@ int try_merge_command(const char *strategy, size_t xopts_nr,
 }
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
+                             struct commit_list *remoteheads,
                              struct commit *head, const char *head_arg)
 {
        int index_fd;
@@ -718,7 +724,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                                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);
@@ -773,10 +779,12 @@ int checkout_fast_forward(const unsigned char *head, const 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;
-       setup_standard_excludes(&dir);
-       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;
@@ -869,39 +877,49 @@ static void read_merge_msg(struct strbuf *msg)
                die_errno(_("Could not read from '%s'"), filename);
 }
 
-static void write_merge_state(void);
-static void abort_commit(const char *err_msg)
+static void write_merge_state(struct commit_list *);
+static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
 {
        if (err_msg)
                error("%s", err_msg);
        fprintf(stderr,
                _("Not committing merge; use 'git commit' to complete the merge.\n"));
-       write_merge_state();
+       write_merge_state(remoteheads);
        exit(1);
 }
 
-static void prepare_to_commit(void)
+static const char merge_editor_comment[] =
+N_("Please enter a commit message to explain why this merge is necessary,\n"
+   "especially if it merges an updated upstream into a topic branch.\n"
+   "\n"
+   "Lines starting with '#' will be ignored, and an empty message aborts\n"
+   "the commit.\n");
+
+static void prepare_to_commit(struct commit_list *remoteheads)
 {
        struct strbuf msg = STRBUF_INIT;
+       const char *comment = _(merge_editor_comment);
        strbuf_addbuf(&msg, &merge_msg);
        strbuf_addch(&msg, '\n');
+       if (0 < option_edit)
+               strbuf_add_lines(&msg, "# ", comment, strlen(comment));
        write_merge_msg(&msg);
        run_hook(get_index_file(), "prepare-commit-msg",
                 git_path("MERGE_MSG"), "merge", NULL, NULL);
-       if (option_edit) {
+       if (0 < option_edit) {
                if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
-                       abort_commit(NULL);
+                       abort_commit(remoteheads, NULL);
        }
        read_merge_msg(&msg);
-       stripspace(&msg, option_edit);
+       stripspace(&msg, 0 < option_edit);
        if (!msg.len)
-               abort_commit(_("Empty commit message."));
+               abort_commit(remoteheads, _("Empty commit message."));
        strbuf_release(&merge_msg);
        strbuf_addbuf(&merge_msg, &msg);
        strbuf_release(&msg);
 }
 
-static int merge_trivial(struct commit *head)
+static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parent = xmalloc(sizeof(*parent));
@@ -912,41 +930,37 @@ static int merge_trivial(struct commit *head)
        parent->next = xmalloc(sizeof(*parent->next));
        parent->next->item = remoteheads->item;
        parent->next->next = NULL;
-       prepare_to_commit();
-       commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
-       finish(head, result_commit, "In-index merge");
+       prepare_to_commit(remoteheads);
+       if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL,
+                       sign_commit))
+               die(_("failed to write commit object"));
+       finish(head, remoteheads, result_commit, "In-index merge");
        drop_save();
        return 0;
 }
 
 static int finish_automerge(struct commit *head,
+                           int head_subsumed,
                            struct commit_list *common,
+                           struct commit_list *remoteheads,
                            unsigned char *result_tree,
                            const char *wt_strategy)
 {
-       struct commit_list *parents = NULL, *j;
+       struct commit_list *parents = NULL;
        struct strbuf buf = STRBUF_INIT;
        unsigned char result_commit[20];
 
        free_commit_list(common);
-       if (allow_fast_forward) {
-               parents = remoteheads;
+       parents = remoteheads;
+       if (!head_subsumed || !allow_fast_forward)
                commit_list_insert(head, &parents);
-               parents = reduce_heads(parents);
-       } else {
-               struct commit_list **pptr = &parents;
-
-               pptr = &commit_list_insert(head,
-                               pptr)->next;
-               for (j = remoteheads; j; j = j->next)
-                       pptr = &commit_list_insert(j->item, pptr)->next;
-       }
        strbuf_addch(&merge_msg, '\n');
-       prepare_to_commit();
-       free_commit_list(remoteheads);
-       commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
+       prepare_to_commit(remoteheads);
+       if (commit_tree(&merge_msg, result_tree, parents, result_commit,
+                       NULL, sign_commit))
+               die(_("failed to write commit object"));
        strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
-       finish(head, result_commit, buf.buf);
+       finish(head, remoteheads, result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
@@ -1051,16 +1065,23 @@ static int setup_with_upstream(const char ***argv)
        return i;
 }
 
-static void write_merge_state(void)
+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)
-               strbuf_addf(&buf, "%s\n",
-                       sha1_to_hex(j->item->object.sha1));
+       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)
@@ -1083,6 +1104,66 @@ static void write_merge_state(void)
        close(fd);
 }
 
+static int default_edit_option(void)
+{
+       static const char name[] = "GIT_MERGE_AUTOEDIT";
+       const char *e = getenv(name);
+       struct stat st_stdin, st_stdout;
+
+       if (have_message)
+               /* an explicit -m msg without --[no-]edit */
+               return 0;
+
+       if (e) {
+               int v = git_config_maybe_bool(name, e);
+               if (v < 0)
+                       die("Bad value '%s' in environment '%s'", e, name);
+               return v;
+       }
+
+       /* Use editor if stdin and stdout are the same and is a tty */
+       return (!fstat(0, &st_stdin) &&
+               !fstat(1, &st_stdout) &&
+               isatty(0) && isatty(1) &&
+               st_stdin.st_dev == st_stdout.st_dev &&
+               st_stdin.st_ino == st_stdout.st_ino &&
+               st_stdin.st_mode == st_stdout.st_mode);
+}
+
+static struct commit_list *collect_parents(struct commit *head_commit,
+                                          int *head_subsumed,
+                                          int argc, const char **argv)
+{
+       int i;
+       struct commit_list *remoteheads = NULL, *parents, *next;
+       struct commit_list **remotes = &remoteheads;
+
+       if (head_commit)
+               remotes = &commit_list_insert(head_commit, remotes)->next;
+       for (i = 0; i < argc; i++) {
+               struct commit *commit = get_merge_parent(argv[i]);
+               if (!commit)
+                       die(_("%s - not something we can merge"), argv[i]);
+               remotes = &commit_list_insert(commit, remotes)->next;
+       }
+       *remotes = NULL;
+
+       parents = reduce_heads(remoteheads);
+
+       *head_subsumed = 1; /* we will flip this to 0 when we find it */
+       for (remoteheads = NULL, remotes = &remoteheads;
+            parents;
+            parents = next) {
+               struct commit *commit = parents->item;
+               next = parents->next;
+               if (commit == head_commit)
+                       *head_subsumed = 0;
+               else
+                       remotes = &commit_list_insert(commit, remotes)->next;
+       }
+       return remoteheads;
+}
+
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
        unsigned char result_tree[20];
@@ -1091,11 +1172,12 @@ 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;
+       int flag, i, ret = 0, head_subsumed;
        int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
        struct commit_list *common = NULL;
        const char *best_strategy = NULL, *wt_strategy = NULL;
-       struct commit_list **remotes = &remoteheads;
+       struct commit_list *remoteheads, *p;
+       void *branch_to_free;
 
        if (argc == 2 && !strcmp(argv[1], "-h"))
                usage_with_options(builtin_merge_usage, builtin_merge_options);
@@ -1104,7 +1186,7 @@ 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 = resolve_ref("HEAD", head_sha1, 0, &flag);
+       branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
        if (branch && !prefixcmp(branch, "refs/heads/"))
                branch += 11;
        if (!branch || is_null_sha1(head_sha1))
@@ -1118,6 +1200,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                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;
@@ -1130,7 +1214,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        die(_("There is no merge to abort (MERGE_HEAD missing)."));
 
                /* Invoke 'git reset --merge' */
-               return cmd_reset(nargc, nargv, prefix);
+               ret = cmd_reset(nargc, nargv, prefix);
+               goto done;
        }
 
        if (read_cache_unmerged())
@@ -1169,9 +1254,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                die(_("You cannot combine --no-ff with --ff-only."));
 
        if (!abort_current_merge) {
-               if (!argc && default_to_upstream)
-                       argc = setup_with_upstream(&argv);
-               else if (argc == 1 && !strcmp(argv[0], "-"))
+               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)
@@ -1193,8 +1281,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                head_arg = argv[1];
                argv += 2;
                argc -= 2;
+               remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
        } else if (!head_commit) {
-               struct object *remote_head;
+               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.
@@ -1208,13 +1297,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (!allow_fast_forward)
                        die(_("Non-fast-forward commit does not make sense into "
                            "an empty head"));
-               remote_head = want_commit(argv[0]);
+               remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+               remote_head = remoteheads->item;
                if (!remote_head)
                        die(_("%s - not something we can merge"), argv[0]);
-               read_empty(remote_head->sha1, 0);
-               update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
-                               DIE_ON_ERR);
-               return 0;
+               read_empty(remote_head->object.sha1, 0);
+               update_ref("initial pull", "HEAD", remote_head->object.sha1,
+                          NULL, 0, DIE_ON_ERR);
+               goto done;
        } else {
                struct strbuf merge_names = STRBUF_INIT;
 
@@ -1222,19 +1312,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                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.
                 */
-               for (i = 0; i < argc; i++)
-                       merge_name(argv[i], &merge_names);
+               remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+               for (p = remoteheads; p; p = p->next)
+                       merge_name(merge_remote_util(p->item)->name, &merge_names);
 
                if (!have_message || shortlog_len) {
-                       fmt_merge_msg(&merge_names, &merge_msg, !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);
                }
@@ -1245,29 +1337,31 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        builtin_merge_options);
 
        strbuf_addstr(&buf, "merge");
-       for (i = 0; i < argc; i++)
-               strbuf_addf(&buf, " %s", argv[i]);
+       for (p = remoteheads; p; p = p->next)
+               strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
        setenv("GIT_REFLOG_ACTION", buf.buf, 0);
        strbuf_reset(&buf);
 
-       for (i = 0; i < argc; i++) {
-               struct object *o;
-               struct commit *commit;
-
-               o = want_commit(argv[i]);
-               if (!o)
-                       die(_("%s - not something we can merge"), argv[i]);
-               commit = lookup_commit(o->sha1);
-               commit->util = (void *)argv[i];
-               remotes = &commit_list_insert(commit, remotes)->next;
-
-               strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
-               setenv(buf.buf, argv[i], 1);
+       for (p = remoteheads; p; p = p->next) {
+               struct commit *commit = p->item;
+               strbuf_addf(&buf, "GITHEAD_%s",
+                           sha1_to_hex(commit->object.sha1));
+               setenv(buf.buf, merge_remote_util(commit)->name, 1);
                strbuf_reset(&buf);
+               if (!fast_forward_only &&
+                   merge_remote_util(commit) &&
+                   merge_remote_util(commit)->obj &&
+                   merge_remote_util(commit)->obj->type == OBJ_TAG)
+                       allow_fast_forward = 0;
        }
 
+       if (option_edit < 0)
+               option_edit = default_edit_option();
+
        if (!use_strategies) {
-               if (!remoteheads->next)
+               if (!remoteheads)
+                       ; /* already up-to-date */
+               else if (!remoteheads->next)
                        add_strategies(pull_twohead, DEFAULT_TWOHEAD);
                else
                        add_strategies(pull_octopus, DEFAULT_OCTOPUS);
@@ -1280,7 +1374,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        allow_trivial = 0;
        }
 
-       if (!remoteheads->next)
+       if (!remoteheads)
+               ; /* already up-to-date */
+       else if (!remoteheads->next)
                common = get_merge_bases(head_commit, remoteheads->item, 1);
        else {
                struct commit_list *list = remoteheads;
@@ -1292,22 +1388,23 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
                   NULL, 0, DIE_ON_ERR);
 
-       if (!common)
+       if (remoteheads && !common)
                ; /* No common ancestors found. We need a real merge. */
-       else if (!remoteheads->next && !common->next &&
-                       common->item == remoteheads->item) {
+       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.");
-               return 0;
+               goto done;
        } else if (allow_fast_forward && !remoteheads->next &&
                        !common->next &&
                        !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
                /* Again the most common case of merging one remote. */
                struct strbuf msg = STRBUF_INIT;
-               struct object *o;
+               struct commit *commit;
                char hex[41];
 
                strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
@@ -1321,16 +1418,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (have_message)
                        strbuf_addstr(&msg,
                                " (no commit created; -m option ignored)");
-               o = want_commit(sha1_to_hex(remoteheads->item->object.sha1));
-               if (!o)
-                       return 1;
+               commit = remoteheads->item;
+               if (!commit) {
+                       ret = 1;
+                       goto done;
+               }
 
-               if (checkout_fast_forward(head_commit->object.sha1, remoteheads->item->object.sha1))
-                       return 1;
+               if (checkout_fast_forward(head_commit->object.sha1,
+                                         commit->object.sha1)) {
+                       ret = 1;
+                       goto done;
+               }
 
-               finish(head_commit, o->sha1, msg.buf);
+               finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
                drop_save();
-               return 0;
+               goto done;
        } else if (!remoteheads->next && common->next)
                ;
                /*
@@ -1345,11 +1447,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                refresh_cache(REFRESH_QUIET);
                if (allow_trivial && !fast_forward_only) {
                        /* See if it is really trivial. */
-                       git_committer_info(IDENT_ERROR_ON_NO_NAME);
+                       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))
-                               return merge_trivial(head_commit);
+                                              head_commit->object.sha1,
+                                              remoteheads->item->object.sha1)) {
+                               ret = merge_trivial(head_commit, remoteheads);
+                               goto done;
+                       }
                        printf(_("Nope.\n"));
                }
        } else {
@@ -1377,7 +1482,7 @@ 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;
                }
        }
 
@@ -1385,7 +1490,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                die(_("Not possible to fast-forward, aborting."));
 
        /* We are going to make a new commit. */
-       git_committer_info(IDENT_ERROR_ON_NO_NAME);
+       git_committer_info(IDENT_STRICT);
 
        /*
         * At this point, we need a real merge.  No matter what strategy
@@ -1418,7 +1523,8 @@ 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_commit, head_arg);
+                                        common, remoteheads,
+                                        head_commit, head_arg);
                if (!option_commit && !ret) {
                        merge_was_ok = 1;
                        /*
@@ -1459,9 +1565,12 @@ 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(head_commit, common, result_tree,
-                                       wt_strategy);
+       if (automerge_was_ok) {
+               ret = finish_automerge(head_commit, head_subsumed,
+                                      common, remoteheads,
+                                      result_tree, wt_strategy);
+               goto done;
+       }
 
        /*
         * Pick the result from the best strategy and have the user fix
@@ -1475,7 +1584,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                else
                        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 {
@@ -1483,18 +1593,22 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                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_commit, head_arg);
+               try_merge_strategy(best_strategy, common, remoteheads,
+                                  head_commit, head_arg);
        }
 
        if (squash)
-               finish(head_commit, NULL, NULL);
+               finish(head_commit, remoteheads, NULL, NULL);
        else
-               write_merge_state();
+               write_merge_state(remoteheads);
 
-       if (merge_was_ok) {
+       if (merge_was_ok)
                fprintf(stderr, _("Automatic merge went well; "
                        "stopped before committing as requested\n"));
-               return 0;
-       } else
-               return suggest_conflicts(option_renormalize);
+       else
+               ret = suggest_conflicts(option_renormalize);
+
+done:
+       free(branch_to_free);
+       return ret;
 }