merge: make usage of commit->util more extensible

The merge-recursive code uses the commit->util field directly to annotate
the commit objects given from the command line, i.e. the remote heads to
be merged, with a single string to be used to describe it in its trace
messages and conflict markers.

Correct this short-signtedness by redefining the field to be a pointer to
a structure "struct merge_remote_desc" that later enhancements can add
more information. Store the original objects we were told to merge in a
field "obj" in this struct, so that we can recover the tag we were told to
merge.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/merge.c b/builtin/merge.c
index 48e7f003d36faafe793bdb8a14863ded603c2e92..8d4eb4e423a2513e7b537416ab397a543b17e6b3 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -406,20 +406,10 @@ 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;
+       struct commit *remote_head;
        unsigned char branch_head[20], buf_sha[20];
        struct strbuf buf = STRBUF_INIT;
        struct strbuf bname = STRBUF_INIT;
@@ -431,7 +421,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        remote = bname.buf;
 
        memset(branch_head, 0, sizeof(branch_head));
-       remote_head = want_commit(remote);
+       remote_head = get_merge_parent(remote);
        if (!remote_head)
                die(_("'%s' does not point to a commit"), remote);
 
@@ -487,7 +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);
@@ -515,7 +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);
@@ -719,7 +709,7 @@ 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);
@@ -1190,7 +1180,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                argv += 2;
                argc -= 2;
        } 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.
@@ -1204,12 +1194,12 @@ 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 = want_commit(argv[0]);
+               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;
@@ -1218,12 +1208,9 @@ 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);
@@ -1251,17 +1238,12 @@ 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 = want_commit(argv[i]);
-               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);
        }
@@ -1307,7 +1289,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        !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));
@@ -1321,14 +1303,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (have_message)
                        strbuf_addstr(&msg,
                                " (no commit created; -m option ignored)");
-               o = want_commit(sha1_to_hex(remoteheads->item->object.sha1));
-               if (!o)
+               commit = remoteheads->item;
+               if (!commit)
                        return 1;
 
-               if (checkout_fast_forward(head_commit->object.sha1, remoteheads->item->object.sha1))
+               if (checkout_fast_forward(head_commit->object.sha1,
+                                         commit->object.sha1))
                        return 1;
 
-               finish(head_commit, o->sha1, msg.buf);
+               finish(head_commit, commit->object.sha1, msg.buf);
                drop_save();
                return 0;
        } else if (!remoteheads->next && common->next)

diff --git a/commit.c b/commit.c
index 73b7e00292ba2de33fa43b5f028fd807a460af34..83ff5035a74464b04aace07879dacd2abe5c2fdc 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -894,3 +894,22 @@ int commit_tree(const char *msg, unsigned char *tree,
        strbuf_release(&buffer);
        return result;
 }
+
+struct commit *get_merge_parent(const char *name)
+{
+       struct object *obj;
+       struct commit *commit;
+       unsigned char sha1[20];
+       if (get_sha1(name, sha1))
+               return NULL;
+       obj = parse_object(sha1);
+       commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
+       if (commit && !commit->util) {
+               struct merge_remote_desc *desc;
+               desc = xmalloc(sizeof(*desc));
+               desc->obj = obj;
+               desc->name = strdup(name);
+               commit->util = desc;
+       }
+       return commit;
+}

diff --git a/commit.h b/commit.h
index 009b113e5bb5d04bdfb116897cc17dc5f5a2fa9c..5b57eab578ee4fd10efedecfca59f2992e686a3c 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -185,4 +185,17 @@ extern int commit_tree(const char *msg, unsigned char *tree,
                struct commit_list *parents, unsigned char *ret,
                const char *author);
 
+struct merge_remote_desc {
+       struct object *obj; /* the named object, could be a tag */
+       const char *name;
+};
+#define merge_remote_util(commit) ((struct merge_remote_desc *)((commit)->util))
+
+/*
+ * Given "name" from the command line to merge, find the commit object
+ * and return it, while storing merge_remote_desc in its ->util field,
+ * to allow callers to tell if we are told to merge a tag.
+ */
+struct commit *get_merge_parent(const char *name);
+
 #endif /* COMMIT_H */

diff --git a/merge-recursive.c b/merge-recursive.c
index cc664c39b66b0bb499dec13a22880a6096423fa6..5a2db296b83d1ab23bfce23913c036a71dc81398 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -38,16 +38,15 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two,
        return lookup_tree(shifted);
 }
 
-/*
- * A virtual commit has (const char *)commit->util set to the name.
- */
-
 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 {
        struct commit *commit = xcalloc(1, sizeof(struct commit));
+       struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
+
+       desc->name = comment;
+       desc->obj = (struct object *)commit;
        commit->tree = tree;
-       commit->util = (void*)comment;
-       /* avoid warnings */
+       commit->util = desc;
        commit->object.parsed = 1;
        return commit;
 }
@@ -184,7 +183,7 @@ static void output_commit_title(struct merge_options *o, struct commit *commit)
        for (i = o->call_depth; i--;)
                fputs("  ", stdout);
        if (commit->util)
-               printf("virtual %s\n", (char *)commit->util);
+               printf("virtual %s\n", merge_remote_util(commit)->name);
        else {
                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
                if (parse_commit(commit) != 0)