commit: teach --amend to carry forward extra headers
[gitweb.git] / builtin / merge.c
index a8dbf4a32f09a1377eb489459837e5a07e36f490..99f1429b350b69055244fe77ae769ae89bea809c 100644 (file)
@@ -50,7 +50,6 @@ static int fast_forward_only, option_edit;
 static int allow_trivial = 1, have_message;
 static struct strbuf merge_msg;
 static struct commit_list *remoteheads;
-static unsigned char head[20], stash[20];
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
 static const char **xopts;
@@ -219,7 +218,7 @@ static void drop_save(void)
        unlink(git_path("MERGE_MODE"));
 }
 
-static void save_state(void)
+static int save_state(unsigned char *stash)
 {
        int len;
        struct child_process cp;
@@ -238,11 +237,12 @@ static void save_state(void)
 
        if (finish_command(&cp) || len < 0)
                die(_("stash failed"));
-       else if (!len)
-               return;
+       else if (!len)          /* no changes */
+               return -1;
        strbuf_setlen(&buffer, buffer.len-1);
        if (get_sha1(buffer.buf, stash))
                die(_("not a valid object: %s"), buffer.buf);
+       return 0;
 }
 
 static void read_empty(unsigned const char *sha1, int verbose)
@@ -280,7 +280,8 @@ static void reset_hard(unsigned const char *sha1, int verbose)
                die(_("read-tree failed"));
 }
 
-static void restore_state(void)
+static void restore_state(const unsigned char *head,
+                         const unsigned char *stash)
 {
        struct strbuf sb = STRBUF_INIT;
        const char *args[] = { "stash", "apply", NULL, NULL };
@@ -310,10 +311,9 @@ static void finish_up_to_date(const char *msg)
        drop_save();
 }
 
-static void squash_message(void)
+static void squash_message(struct commit *commit)
 {
        struct rev_info rev;
-       struct commit *commit;
        struct strbuf out = STRBUF_INIT;
        struct commit_list *j;
        int fd;
@@ -328,7 +328,6 @@ static void squash_message(void)
        rev.ignore_merges = 1;
        rev.commit_format = CMIT_FMT_MEDIUM;
 
-       commit = lookup_commit(head);
        commit->object.flags |= UNINTERESTING;
        add_pending_object(&rev, &commit->object, NULL);
 
@@ -357,9 +356,11 @@ static void squash_message(void)
        strbuf_release(&out);
 }
 
-static void finish(const unsigned char *new_head, const char *msg)
+static void finish(struct commit *head_commit,
+                  const unsigned char *new_head, const char *msg)
 {
        struct strbuf reflog_message = STRBUF_INIT;
+       const unsigned char *head = head_commit->object.sha1;
 
        if (!msg)
                strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -370,7 +371,7 @@ static void finish(const unsigned char *new_head, const char *msg)
                        getenv("GIT_REFLOG_ACTION"), msg);
        }
        if (squash) {
-               squash_message();
+               squash_message(head_commit);
        } else {
                if (verbosity >= 0 && !merge_msg.len)
                        printf(_("No merge message -- not updating HEAD\n"));
@@ -408,7 +409,7 @@ static void finish(const unsigned char *new_head, const char *msg)
 /* Get the name for the merge commit's message. */
 static void merge_name(const char *remote, struct strbuf *msg)
 {
-       struct object *remote_head;
+       struct commit *remote_head;
        unsigned char branch_head[20], buf_sha[20];
        struct strbuf buf = STRBUF_INIT;
        struct strbuf bname = STRBUF_INIT;
@@ -420,7 +421,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        remote = bname.buf;
 
        memset(branch_head, 0, sizeof(branch_head));
-       remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
+       remote_head = get_merge_parent(remote);
        if (!remote_head)
                die(_("'%s' does not point to a commit"), remote);
 
@@ -430,6 +431,11 @@ 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);
@@ -471,7 +477,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
                if (resolve_ref(truname.buf, buf_sha, 1, NULL)) {
                        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);
@@ -499,7 +505,7 @@ 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);
@@ -663,7 +669,7 @@ int try_merge_command(const char *strategy, size_t xopts_nr,
 }
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
-                             const char *head_arg)
+                             struct commit *head, const char *head_arg)
 {
        int index_fd;
        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
@@ -703,13 +709,13 @@ 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);
 
                index_fd = hold_locked_index(lock, 1);
-               clean = merge_recursive(&o, lookup_commit(head),
+               clean = merge_recursive(&o, head,
                                remoteheads->item, reversed, &result);
                if (active_cache_changed &&
                                (write_cache(index_fd, active_cache, active_nr) ||
@@ -884,25 +890,26 @@ static void prepare_to_commit(void)
        strbuf_release(&msg);
 }
 
-static int merge_trivial(void)
+static int merge_trivial(struct commit *head)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parent = xmalloc(sizeof(*parent));
 
        write_tree_trivial(result_tree);
        printf(_("Wonderful.\n"));
-       parent->item = lookup_commit(head);
+       parent->item = 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(result_commit, "In-index merge");
+       finish(head, result_commit, "In-index merge");
        drop_save();
        return 0;
 }
 
-static int finish_automerge(struct commit_list *common,
+static int finish_automerge(struct commit *head,
+                           struct commit_list *common,
                            unsigned char *result_tree,
                            const char *wt_strategy)
 {
@@ -913,12 +920,12 @@ static int finish_automerge(struct commit_list *common,
        free_commit_list(common);
        if (allow_fast_forward) {
                parents = remoteheads;
-               commit_list_insert(lookup_commit(head), &parents);
+               commit_list_insert(head, &parents);
                parents = reduce_heads(parents);
        } else {
                struct commit_list **pptr = &parents;
 
-               pptr = &commit_list_insert(lookup_commit(head),
+               pptr = &commit_list_insert(head,
                                pptr)->next;
                for (j = remoteheads; j; j = j->next)
                        pptr = &commit_list_insert(j->item, pptr)->next;
@@ -928,7 +935,7 @@ static int finish_automerge(struct commit_list *common,
        free_commit_list(remoteheads);
        commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
        strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
-       finish(result_commit, buf.buf);
+       finish(head, result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
@@ -962,7 +969,8 @@ static int suggest_conflicts(int renormalizing)
        return 1;
 }
 
-static struct commit *is_old_style_invocation(int argc, const char **argv)
+static struct commit *is_old_style_invocation(int argc, const char **argv,
+                                             const unsigned char *head)
 {
        struct commit *second_token = NULL;
        if (argc > 2) {
@@ -1037,9 +1045,16 @@ static void write_merge_state(void)
        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));
+       }
        fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
                die_errno(_("Could not open '%s' for writing"),
@@ -1064,9 +1079,12 @@ static void write_merge_state(void)
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
        unsigned char result_tree[20];
+       unsigned char stash[20];
+       unsigned char head_sha1[20];
+       struct commit *head_commit;
        struct strbuf buf = STRBUF_INIT;
        const char *head_arg;
-       int flag, head_invalid = 0, i;
+       int flag, i;
        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;
@@ -1079,11 +1097,13 @@ 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, 0, &flag);
+       branch = resolve_ref("HEAD", head_sha1, 0, &flag);
        if (branch && !prefixcmp(branch, "refs/heads/"))
                branch += 11;
-       if (is_null_sha1(head))
-               head_invalid = 1;
+       if (!branch || is_null_sha1(head_sha1))
+               head_commit = NULL;
+       else
+               head_commit = lookup_commit_or_die(head_sha1, "HEAD");
 
        git_config(git_merge_config, NULL);
 
@@ -1160,13 +1180,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * additional safety measure to check for it.
         */
 
-       if (!have_message && is_old_style_invocation(argc, argv)) {
+       if (!have_message && head_commit &&
+           is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
                strbuf_addstr(&merge_msg, argv[0]);
                head_arg = argv[1];
                argv += 2;
                argc -= 2;
-       } else if (head_invalid) {
-               struct object *remote_head;
+       } else if (!head_commit) {
+               struct commit *remote_head;
                /*
                 * If the merged head is a valid one there is no reason
                 * to forbid "git merge" into a branch yet to be born.
@@ -1180,12 +1201,12 @@ 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 = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
+               remote_head = get_merge_parent(argv[0]);
                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);
+               read_empty(remote_head->object.sha1, 0);
+               update_ref("initial pull", "HEAD", remote_head->object.sha1,
+                          NULL, 0, DIE_ON_ERR);
                return 0;
        } else {
                struct strbuf merge_names = STRBUF_INIT;
@@ -1194,25 +1215,26 @@ 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);
 
                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);
                }
        }
 
-       if (head_invalid || !argc)
+       if (!head_commit || !argc)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
 
@@ -1223,19 +1245,20 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        strbuf_reset(&buf);
 
        for (i = 0; i < argc; i++) {
-               struct object *o;
-               struct commit *commit;
-
-               o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
-               if (!o)
+               struct commit *commit = get_merge_parent(argv[i]);
+               if (!commit)
                        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));
+               strbuf_addf(&buf, "GITHEAD_%s",
+                           sha1_to_hex(commit->object.sha1));
                setenv(buf.buf, argv[i], 1);
                strbuf_reset(&buf);
+               if (merge_remote_util(commit) &&
+                   merge_remote_util(commit)->obj &&
+                   merge_remote_util(commit)->obj->type == OBJ_TAG) {
+                       option_edit = 1;
+                       allow_fast_forward = 0;
+               }
        }
 
        if (!use_strategies) {
@@ -1253,17 +1276,16 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        }
 
        if (!remoteheads->next)
-               common = get_merge_bases(lookup_commit(head),
-                               remoteheads->item, 1);
+               common = get_merge_bases(head_commit, remoteheads->item, 1);
        else {
                struct commit_list *list = remoteheads;
-               commit_list_insert(lookup_commit(head), &list);
+               commit_list_insert(head_commit, &list);
                common = get_octopus_merge_bases(list);
                free(list);
        }
 
-       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
-               DIE_ON_ERR);
+       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
+                  NULL, 0, DIE_ON_ERR);
 
        if (!common)
                ; /* No common ancestors found. We need a real merge. */
@@ -1277,13 +1299,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                return 0;
        } else if (allow_fast_forward && !remoteheads->next &&
                        !common->next &&
-                       !hashcmp(common->item->object.sha1, head)) {
+                       !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
                /* Again the most common case of merging one remote. */
                struct strbuf msg = STRBUF_INIT;
-               struct object *o;
+               struct commit *commit;
                char hex[41];
 
-               strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
+               strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
 
                if (verbosity >= 0)
                        printf(_("Updating %s..%s\n"),
@@ -1294,15 +1316,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (have_message)
                        strbuf_addstr(&msg,
                                " (no commit created; -m option ignored)");
-               o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
-                       0, NULL, OBJ_COMMIT);
-               if (!o)
+               commit = remoteheads->item;
+               if (!commit)
                        return 1;
 
-               if (checkout_fast_forward(head, remoteheads->item->object.sha1))
+               if (checkout_fast_forward(head_commit->object.sha1,
+                                         commit->object.sha1))
                        return 1;
 
-               finish(o->sha1, msg.buf);
+               finish(head_commit, commit->object.sha1, msg.buf);
                drop_save();
                return 0;
        } else if (!remoteheads->next && common->next)
@@ -1322,8 +1344,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        git_committer_info(IDENT_ERROR_ON_NO_NAME);
                        printf(_("Trying really trivial in-index merge...\n"));
                        if (!read_tree_trivial(common->item->object.sha1,
-                                       head, remoteheads->item->object.sha1))
-                               return merge_trivial();
+                                       head_commit->object.sha1, remoteheads->item->object.sha1))
+                               return merge_trivial(head_commit);
                        printf(_("Nope.\n"));
                }
        } else {
@@ -1342,8 +1364,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                         * merge_bases again, otherwise "git merge HEAD^
                         * HEAD^^" would be missed.
                         */
-                       common_one = get_merge_bases(lookup_commit(head),
-                               j->item, 1);
+                       common_one = get_merge_bases(head_commit, j->item, 1);
                        if (hashcmp(common_one->item->object.sha1,
                                j->item->object.sha1)) {
                                up_to_date = 0;
@@ -1370,21 +1391,18 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * sync with the head commit.  The strategies are responsible
         * to ensure this.
         */
-       if (use_strategies_nr != 1) {
-               /*
-                * Stash away the local changes so that we can try more
-                * than one.
-                */
-               save_state();
-       } else {
-               memcpy(stash, null_sha1, 20);
-       }
+       if (use_strategies_nr == 1 ||
+           /*
+            * Stash away the local changes so that we can try more than one.
+            */
+           save_state(stash))
+               hashcpy(stash, null_sha1);
 
        for (i = 0; i < use_strategies_nr; i++) {
                int ret;
                if (i) {
                        printf(_("Rewinding the tree to pristine...\n"));
-                       restore_state();
+                       restore_state(head_commit->object.sha1, stash);
                }
                if (use_strategies_nr != 1)
                        printf(_("Trying merge strategy %s...\n"),
@@ -1396,7 +1414,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                wt_strategy = use_strategies[i]->name;
 
                ret = try_merge_strategy(use_strategies[i]->name,
-                       common, head_arg);
+                                        common, head_commit, head_arg);
                if (!option_commit && !ret) {
                        merge_was_ok = 1;
                        /*
@@ -1438,14 +1456,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * auto resolved the merge cleanly.
         */
        if (automerge_was_ok)
-               return finish_automerge(common, result_tree, wt_strategy);
+               return finish_automerge(head_commit, common, result_tree,
+                                       wt_strategy);
 
        /*
         * Pick the result from the best strategy and have the user fix
         * it up.
         */
        if (!best_strategy) {
-               restore_state();
+               restore_state(head_commit->object.sha1, stash);
                if (use_strategies_nr > 1)
                        fprintf(stderr,
                                _("No merge strategy handled the merge.\n"));
@@ -1457,14 +1476,14 @@ 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();
+               restore_state(head_commit->object.sha1, stash);
                printf(_("Using the %s to prepare resolving by hand.\n"),
                        best_strategy);
-               try_merge_strategy(best_strategy, common, head_arg);
+               try_merge_strategy(best_strategy, common, head_commit, head_arg);
        }
 
        if (squash)
-               finish(NULL, NULL);
+               finish(head_commit, NULL, NULL);
        else
                write_merge_state();