diff --git a/blame.c b/blame.c
index 25d3bcf647..7c0b62cf3f 100644
--- a/blame.c
+++ b/blame.c
@@ -110,8 +110,8 @@ static struct patch *get_patch(struct commit *commit, struct commit *other)
 	xdemitconf_t xecfg;
 	mmfile_t file_c, file_o;
 	xdemitcb_t ecb;
-	struct util_info *info_c = (struct util_info *)commit->object.util;
-	struct util_info *info_o = (struct util_info *)other->object.util;
+	struct util_info *info_c = (struct util_info *)commit->util;
+	struct util_info *info_o = (struct util_info *)other->util;
 	struct timeval tv_start, tv_end;
 
 	get_blob(commit);
@@ -197,7 +197,7 @@ static int get_blob_sha1_internal(const unsigned char *sha1, const char *base,
 
 static void get_blob(struct commit *commit)
 {
-	struct util_info *info = commit->object.util;
+	struct util_info *info = commit->util;
 	char type[20];
 
 	if (info->buf)
@@ -223,8 +223,8 @@ static void print_patch(struct patch *p)
 /* For debugging only */
 static void print_map(struct commit *cmit, struct commit *other)
 {
-	struct util_info *util = cmit->object.util;
-	struct util_info *util2 = other->object.util;
+	struct util_info *util = cmit->util;
+	struct util_info *util2 = other->util;
 
 	int i;
 	int max =
@@ -259,8 +259,8 @@ static void print_map(struct commit *cmit, struct commit *other)
 static void fill_line_map(struct commit *commit, struct commit *other,
 			  struct patch *p)
 {
-	struct util_info *util = commit->object.util;
-	struct util_info *util2 = other->object.util;
+	struct util_info *util = commit->util;
+	struct util_info *util2 = other->util;
 	int *map = util->line_map;
 	int *map2 = util2->line_map;
 	int cur_chunk = 0;
@@ -322,14 +322,14 @@ static void fill_line_map(struct commit *commit, struct commit *other,
 
 static int map_line(struct commit *commit, int line)
 {
-	struct util_info *info = commit->object.util;
+	struct util_info *info = commit->util;
 	assert(line >= 0 && line < info->num_lines);
 	return info->line_map[line];
 }
 
 static struct util_info* get_util(struct commit *commit)
 {
-	struct util_info *util = commit->object.util;
+	struct util_info *util = commit->util;
 
 	if (util)
 		return util;
@@ -340,13 +340,13 @@ static struct util_info* get_util(struct commit *commit)
 	util->line_map = NULL;
 	util->num_lines = -1;
 	util->pathname = NULL;
-	commit->object.util = util;
+	commit->util = util;
 	return util;
 }
 
 static int fill_util_info(struct commit *commit)
 {
-	struct util_info *util = commit->object.util;
+	struct util_info *util = commit->util;
 
 	assert(util);
 	assert(util->pathname);
@@ -359,7 +359,7 @@ static int fill_util_info(struct commit *commit)
 
 static void alloc_line_map(struct commit *commit)
 {
-	struct util_info *util = commit->object.util;
+	struct util_info *util = commit->util;
 	int i;
 
 	if (util->line_map)
@@ -383,7 +383,7 @@ static void alloc_line_map(struct commit *commit)
 
 static void init_first_commit(struct commit* commit, const char* filename)
 {
-	struct util_info* util = commit->object.util;
+	struct util_info* util = commit->util;
 	int i;
 
 	util->pathname = filename;
@@ -392,7 +392,7 @@ static void init_first_commit(struct commit* commit, const char* filename)
 
 	alloc_line_map(commit);
 
-	util = commit->object.util;
+	util = commit->util;
 
 	for (i = 0; i < util->num_lines; i++)
 		util->line_map[i] = i;
@@ -413,7 +413,7 @@ static void process_commits(struct rev_info *rev, const char *path,
 	assert(commit);
 	init_first_commit(commit, path);
 
-	util = commit->object.util;
+	util = commit->util;
 	num_blame_lines = util->num_lines;
 	blame_lines = xmalloc(sizeof(struct commit *) * num_blame_lines);
 	blame_contents = util->buf;
@@ -452,7 +452,7 @@ static void process_commits(struct rev_info *rev, const char *path,
 			continue;
 
 		alloc_line_map(commit);
-		util = commit->object.util;
+		util = commit->util;
 
 		for (parents = commit->parents;
 		     parents != NULL; parents = parents->next) {
@@ -512,7 +512,7 @@ static int compare_tree_path(struct rev_info* revs,
 {
 	int ret;
 	const char* paths[2];
-	struct util_info* util = c2->object.util;
+	struct util_info* util = c2->util;
 	paths[0] = util->pathname;
 	paths[1] = NULL;
 
@@ -541,7 +541,7 @@ static int same_tree_as_empty_path(struct rev_info *revs, struct tree* t1,
 
 static const char* find_rename(struct commit* commit, struct commit* parent)
 {
-	struct util_info* cutil = commit->object.util;
+	struct util_info* cutil = commit->util;
 	struct diff_options diff_opts;
 	const char *paths[1];
 	int i;
@@ -585,7 +585,7 @@ static void simplify_commit(struct rev_info *revs, struct commit *commit)
 		return;
 
 	if (!commit->parents) {
-		struct util_info* util = commit->object.util;
+		struct util_info* util = commit->util;
 		if (!same_tree_as_empty_path(revs, commit->tree,
 					     util->pathname))
 			commit->object.flags |= TREECHANGE;
@@ -612,7 +612,7 @@ static void simplify_commit(struct rev_info *revs, struct commit *commit)
 		case REV_TREE_NEW:
 		{
 
-			struct util_info* util = commit->object.util;
+			struct util_info* util = commit->util;
 			if (revs->remove_empty_trees &&
 			    same_tree_as_empty_path(revs, p->tree,
 						    util->pathname)) {
@@ -709,13 +709,13 @@ static const char* format_time(unsigned long time, const char* tz_str,
 
 static void topo_setter(struct commit* c, void* data)
 {
-	struct util_info* util = c->object.util;
+	struct util_info* util = c->util;
 	util->topo_data = data;
 }
 
 static void* topo_getter(struct commit* c)
 {
-	struct util_info* util = c->object.util;
+	struct util_info* util = c->util;
 	return util->topo_data;
 }
 
@@ -863,7 +863,7 @@ int main(int argc, const char **argv)
 		struct util_info* u;
 		if (!c)
 			c = initial;
-		u = c->object.util;
+		u = c->util;
 
 		if (!found_rename && strcmp(filename, u->pathname))
 			found_rename = 1;
@@ -881,7 +881,7 @@ int main(int argc, const char **argv)
 		if (!c)
 			c = initial;
 
-		u = c->object.util;
+		u = c->util;
 		get_commit_info(c, &ci);
 		fwrite(sha1_to_hex(c->object.sha1), sha1_len, 1, stdout);
 		if(compability) {
diff --git a/blob.c b/blob.c
index c1fdd861c3..7377008744 100644
--- a/blob.c
+++ b/blob.c
@@ -10,14 +10,14 @@ struct blob *lookup_blob(const unsigned char *sha1)
 	if (!obj) {
 		struct blob *ret = xcalloc(1, sizeof(struct blob));
 		created_object(sha1, &ret->object);
-		ret->object.type = blob_type;
+		ret->object.type = TYPE_BLOB;
 		return ret;
 	}
 	if (!obj->type)
-		obj->type = blob_type;
-	if (obj->type != blob_type) {
-		error("Object %s is a %s, not a blob", 
-		      sha1_to_hex(sha1), obj->type);
+		obj->type = TYPE_BLOB;
+	if (obj->type != TYPE_BLOB) {
+		error("Object %s is a %s, not a blob",
+		      sha1_to_hex(sha1), typename(obj->type));
 		return NULL;
 	}
 	return (struct blob *) obj;
diff --git a/builtin-diff.c b/builtin-diff.c
index 27451d5613..6ac3d4b8ca 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -303,9 +303,9 @@ int cmd_diff(int argc, const char **argv, char **envp)
 		obj = deref_tag(obj, NULL, 0);
 		if (!obj)
 			die("invalid object '%s' given.", name);
-		if (!strcmp(obj->type, commit_type))
+		if (obj->type == TYPE_COMMIT)
 			obj = &((struct commit *)obj)->tree->object;
-		if (!strcmp(obj->type, tree_type)) {
+		if (obj->type == TYPE_TREE) {
 			if (ARRAY_SIZE(ent) <= ents)
 				die("more than %d trees given: '%s'",
 				    (int) ARRAY_SIZE(ent), name);
@@ -315,7 +315,7 @@ int cmd_diff(int argc, const char **argv, char **envp)
 			ents++;
 			continue;
 		}
-		if (!strcmp(obj->type, blob_type)) {
+		if (obj->type == TYPE_BLOB) {
 			if (2 <= blobs)
 				die("more than two blobs given: '%s'", name);
 			memcpy(blob[blobs].sha1, obj->sha1, 20);
diff --git a/builtin-grep.c b/builtin-grep.c
index 5fac5701e6..9806499263 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -630,10 +630,9 @@ static int grep_tree(struct grep_opt *opt, const char **paths,
 static int grep_object(struct grep_opt *opt, const char **paths,
 		       struct object *obj, const char *name)
 {
-	if (!strcmp(obj->type, blob_type))
+	if (obj->type == TYPE_BLOB)
 		return grep_sha1(opt, obj->sha1, name);
-	if (!strcmp(obj->type, commit_type) ||
-	    !strcmp(obj->type, tree_type)) {
+	if (obj->type == TYPE_COMMIT || obj->type == TYPE_TREE) {
 		struct tree_desc tree;
 		void *data;
 		int hit;
@@ -646,7 +645,7 @@ static int grep_object(struct grep_opt *opt, const char **paths,
 		free(data);
 		return hit;
 	}
-	die("unable to grep from object of type %s", obj->type);
+	die("unable to grep from object of type %s", typename(obj->type));
 }
 
 static const char builtin_grep_usage[] =
diff --git a/builtin-log.c b/builtin-log.c
index f4d974a7b8..9187fd337b 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -40,6 +40,8 @@ static int cmd_log_wc(int argc, const char **argv, char **envp,
 		log_tree_commit(rev, commit);
 		free(commit->buffer);
 		commit->buffer = NULL;
+		free_commit_list(commit->parents);
+		commit->parents = NULL;
 	}
 	return 0;
 }
@@ -218,8 +220,11 @@ int cmd_format_patch(int argc, const char **argv, char **envp)
 		}
 		else if (!strcmp(argv[i], "--signoff") ||
 			 !strcmp(argv[i], "-s")) {
-			const char *committer = git_committer_info(1);
-			const char *endpos = strchr(committer, '>');
+			const char *committer;
+			const char *endpos;
+			setup_ident();
+			committer = git_committer_info(1);
+			endpos = strchr(committer, '>');
 			if (!endpos)
 				die("bogos committer info %s\n", committer);
 			add_signoff = xmalloc(endpos - committer + 2);
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index e885624255..71353eb19d 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -89,6 +89,14 @@ static void show_commit(struct commit *commit)
 		printf("%s%c", pretty_header, hdr_termination);
 	}
 	fflush(stdout);
+	if (commit->parents) {
+		free_commit_list(commit->parents);
+		commit->parents = NULL;
+	}
+	if (commit->buffer) {
+		free(commit->buffer);
+		commit->buffer = NULL;
+	}
 }
 
 static struct object_list **process_blob(struct blob *blob,
@@ -158,16 +166,16 @@ static void show_commit_list(struct rev_info *revs)
 		const char *name = pending->name;
 		if (obj->flags & (UNINTERESTING | SEEN))
 			continue;
-		if (obj->type == tag_type) {
+		if (obj->type == TYPE_TAG) {
 			obj->flags |= SEEN;
 			p = add_object(obj, p, NULL, name);
 			continue;
 		}
-		if (obj->type == tree_type) {
+		if (obj->type == TYPE_TREE) {
 			p = process_tree((struct tree *)obj, p, NULL, name);
 			continue;
 		}
-		if (obj->type == blob_type) {
+		if (obj->type == TYPE_BLOB) {
 			p = process_blob((struct blob *)obj, p, NULL, name);
 			continue;
 		}
diff --git a/builtin-show-branch.c b/builtin-show-branch.c
index 2895140915..09d8227862 100644
--- a/builtin-show-branch.c
+++ b/builtin-show-branch.c
@@ -15,7 +15,7 @@ static const char **default_arg = NULL;
 #define UNINTERESTING	01
 
 #define REV_SHIFT	 2
-#define MAX_REVS	29 /* should not exceed bits_per_int - REV_SHIFT */
+#define MAX_REVS	(FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
 
 static struct commit *interesting(struct commit_list *list)
 {
@@ -51,9 +51,9 @@ struct commit_name {
 static void name_commit(struct commit *commit, const char *head_name, int nth)
 {
 	struct commit_name *name;
-	if (!commit->object.util)
-		commit->object.util = xmalloc(sizeof(struct commit_name));
-	name = commit->object.util;
+	if (!commit->util)
+		commit->util = xmalloc(sizeof(struct commit_name));
+	name = commit->util;
 	name->head_name = head_name;
 	name->generation = nth;
 }
@@ -65,8 +65,8 @@ static void name_commit(struct commit *commit, const char *head_name, int nth)
  */
 static void name_parent(struct commit *commit, struct commit *parent)
 {
-	struct commit_name *commit_name = commit->object.util;
-	struct commit_name *parent_name = parent->object.util;
+	struct commit_name *commit_name = commit->util;
+	struct commit_name *parent_name = parent->util;
 	if (!commit_name)
 		return;
 	if (!parent_name ||
@@ -80,12 +80,12 @@ static int name_first_parent_chain(struct commit *c)
 	int i = 0;
 	while (c) {
 		struct commit *p;
-		if (!c->object.util)
+		if (!c->util)
 			break;
 		if (!c->parents)
 			break;
 		p = c->parents->item;
-		if (!p->object.util) {
+		if (!p->util) {
 			name_parent(c, p);
 			i++;
 		}
@@ -106,7 +106,7 @@ static void name_commits(struct commit_list *list,
 	/* First give names to the given heads */
 	for (cl = list; cl; cl = cl->next) {
 		c = cl->item;
-		if (c->object.util)
+		if (c->util)
 			continue;
 		for (i = 0; i < num_rev; i++) {
 			if (rev[i] == c) {
@@ -132,9 +132,9 @@ static void name_commits(struct commit_list *list,
 			struct commit_name *n;
 			int nth;
 			c = cl->item;
-			if (!c->object.util)
+			if (!c->util)
 				continue;
-			n = c->object.util;
+			n = c->util;
 			parents = c->parents;
 			nth = 0;
 			while (parents) {
@@ -142,7 +142,7 @@ static void name_commits(struct commit_list *list,
 				char newname[1000], *en;
 				parents = parents->next;
 				nth++;
-				if (p->object.util)
+				if (p->util)
 					continue;
 				en = newname;
 				switch (n->generation) {
@@ -257,7 +257,7 @@ static void join_revs(struct commit_list **list_p,
 static void show_one_commit(struct commit *commit, int no_name)
 {
 	char pretty[256], *cp;
-	struct commit_name *name = commit->object.util;
+	struct commit_name *name = commit->util;
 	if (commit->object.parsed)
 		pretty_print_commit(CMIT_FMT_ONELINE, commit, ~0,
 				    pretty, sizeof(pretty), 0, NULL, NULL);
diff --git a/commit.c b/commit.c
index 94f470b75c..5914200a2f 100644
--- a/commit.c
+++ b/commit.c
@@ -56,10 +56,10 @@ static struct commit *check_commit(struct object *obj,
 				   const unsigned char *sha1,
 				   int quiet)
 {
-	if (obj->type != commit_type) {
+	if (obj->type != TYPE_COMMIT) {
 		if (!quiet)
 			error("Object %s is a %s, not a commit",
-			      sha1_to_hex(sha1), obj->type);
+			      sha1_to_hex(sha1), typename(obj->type));
 		return NULL;
 	}
 	return (struct commit *) obj;
@@ -86,11 +86,11 @@ struct commit *lookup_commit(const unsigned char *sha1)
 	if (!obj) {
 		struct commit *ret = xcalloc(1, sizeof(struct commit));
 		created_object(sha1, &ret->object);
-		ret->object.type = commit_type;
+		ret->object.type = TYPE_COMMIT;
 		return ret;
 	}
 	if (!obj->type)
-		obj->type = commit_type;
+		obj->type = TYPE_COMMIT;
 	return check_commit(obj, sha1, 0);
 }
 
@@ -711,12 +711,12 @@ int count_parents(struct commit * commit)
 
 void topo_sort_default_setter(struct commit *c, void *data)
 {
-	c->object.util = data;
+	c->util = data;
 }
 
 void *topo_sort_default_getter(struct commit *c)
 {
-	return c->object.util;
+	return c->util;
 }
 
 /*
diff --git a/commit.h b/commit.h
index c9de1677e9..7c9ca3fbed 100644
--- a/commit.h
+++ b/commit.h
@@ -11,6 +11,7 @@ struct commit_list {
 
 struct commit {
 	struct object object;
+	void *util;
 	unsigned long date;
 	struct commit_list *parents;
 	struct tree *tree;
diff --git a/describe.c b/describe.c
index 8a9cd5d52c..aa3434a4cb 100644
--- a/describe.c
+++ b/describe.c
@@ -67,7 +67,7 @@ static int get_name(const char *path, const unsigned char *sha1)
 	 * Otherwise only annotated tags are used.
 	 */
 	if (!strncmp(path, "refs/tags/", 10)) {
-		if (object->type == tag_type)
+		if (object->type == TYPE_TAG)
 			prio = 2;
 		else
 			prio = 1;
diff --git a/fetch-pack.c b/fetch-pack.c
index 8371348556..7d23a8071a 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -46,7 +46,7 @@ static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
 {
 	struct object *o = deref_tag(parse_object(sha1), path, 0);
 
-	if (o && o->type == commit_type)
+	if (o && o->type == TYPE_COMMIT)
 		rev_list_push((struct commit *)o, SEEN);
 
 	return 0;
@@ -251,14 +251,14 @@ static int mark_complete(const char *path, const unsigned char *sha1)
 {
 	struct object *o = parse_object(sha1);
 
-	while (o && o->type == tag_type) {
+	while (o && o->type == TYPE_TAG) {
 		struct tag *t = (struct tag *) o;
 		if (!t->tagged)
 			break; /* broken repository */
 		o->flags |= COMPLETE;
 		o = parse_object(t->tagged->sha1);
 	}
-	if (o && o->type == commit_type) {
+	if (o && o->type == TYPE_COMMIT) {
 		struct commit *commit = (struct commit *)o;
 		commit->object.flags |= COMPLETE;
 		insert_by_date(commit, &complete);
@@ -352,7 +352,7 @@ static int everything_local(struct ref **refs, int nr_match, char **match)
 		 * in sync with the other side at some time after
 		 * that (it is OK if we guess wrong here).
 		 */
-		if (o->type == commit_type) {
+		if (o->type == TYPE_COMMIT) {
 			struct commit *commit = (struct commit *)o;
 			if (!cutoff || cutoff < commit->date)
 				cutoff = commit->date;
@@ -371,7 +371,7 @@ static int everything_local(struct ref **refs, int nr_match, char **match)
 		struct object *o = deref_tag(lookup_object(ref->old_sha1),
 					     NULL, 0);
 
-		if (!o || o->type != commit_type || !(o->flags & COMPLETE))
+		if (!o || o->type != TYPE_COMMIT || !(o->flags & COMPLETE))
 			continue;
 
 		if (!(o->flags & SEEN)) {
diff --git a/fetch.c b/fetch.c
index cf6c99490c..238032b798 100644
--- a/fetch.c
+++ b/fetch.c
@@ -118,27 +118,27 @@ static struct object_list **process_queue_end = &process_queue;
 
 static int process_object(struct object *obj)
 {
-	if (obj->type == commit_type) {
+	if (obj->type == TYPE_COMMIT) {
 		if (process_commit((struct commit *)obj))
 			return -1;
 		return 0;
 	}
-	if (obj->type == tree_type) {
+	if (obj->type == TYPE_TREE) {
 		if (process_tree((struct tree *)obj))
 			return -1;
 		return 0;
 	}
-	if (obj->type == blob_type) {
+	if (obj->type == TYPE_BLOB) {
 		return 0;
 	}
-	if (obj->type == tag_type) {
+	if (obj->type == TYPE_TAG) {
 		if (process_tag((struct tag *)obj))
 			return -1;
 		return 0;
 	}
 	return error("Unable to determine requirements "
 		     "of type %s for %s",
-		     obj->type, sha1_to_hex(obj->sha1));
+		     typename(obj->type), sha1_to_hex(obj->sha1));
 }
 
 static int process(struct object *obj)
@@ -179,9 +179,7 @@ static int loop(void)
 		 */
 		if (! (obj->flags & TO_SCAN)) {
 			if (fetch(obj->sha1)) {
-				report_missing(obj->type
-					       ? obj->type
-					       : "object", obj->sha1);
+				report_missing(typename(obj->type), obj->sha1);
 				return -1;
 			}
 		}
diff --git a/fsck-objects.c b/fsck-objects.c
index 33ce366e99..2b1aab488f 100644
--- a/fsck-objects.c
+++ b/fsck-objects.c
@@ -34,7 +34,7 @@ static void objreport(struct object *obj, const char *severity,
                       const char *err, va_list params)
 {
 	fprintf(stderr, "%s in %s %s: ",
-	        severity, obj->type, sha1_to_hex(obj->sha1));
+	        severity, typename(obj->type), sha1_to_hex(obj->sha1));
 	vfprintf(stderr, err, params);
 	fputs("\n", stderr);
 }
@@ -74,7 +74,7 @@ static void check_connectivity(void)
 				; /* it is in pack */
 			else
 				printf("missing %s %s\n",
-				       obj->type, sha1_to_hex(obj->sha1));
+				       typename(obj->type), sha1_to_hex(obj->sha1));
 			continue;
 		}
 
@@ -87,20 +87,20 @@ static void check_connectivity(void)
 				    (has_sha1_file(ref->sha1)))
 					continue;
 				printf("broken link from %7s %s\n",
-				       obj->type, sha1_to_hex(obj->sha1));
+				       typename(obj->type), sha1_to_hex(obj->sha1));
 				printf("              to %7s %s\n",
-				       ref->type, sha1_to_hex(ref->sha1));
+				       typename(ref->type), sha1_to_hex(ref->sha1));
 			}
 		}
 
 		if (show_unreachable && !(obj->flags & REACHABLE)) {
 			printf("unreachable %s %s\n",
-			       obj->type, sha1_to_hex(obj->sha1));
+			       typename(obj->type), sha1_to_hex(obj->sha1));
 			continue;
 		}
 
 		if (!obj->used) {
-			printf("dangling %s %s\n", obj->type, 
+			printf("dangling %s %s\n", typename(obj->type),
 			       sha1_to_hex(obj->sha1));
 		}
 	}
@@ -282,7 +282,7 @@ static int fsck_tag(struct tag *tag)
 	if (!show_tags)
 		return 0;
 
-	printf("tagged %s %s", tagged->type, sha1_to_hex(tagged->sha1));
+	printf("tagged %s %s", typename(tagged->type), sha1_to_hex(tagged->sha1));
 	printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 	return 0;
 }
@@ -295,16 +295,16 @@ static int fsck_sha1(unsigned char *sha1)
 	if (obj->flags & SEEN)
 		return 0;
 	obj->flags |= SEEN;
-	if (obj->type == blob_type)
+	if (obj->type == TYPE_BLOB)
 		return 0;
-	if (obj->type == tree_type)
+	if (obj->type == TYPE_TREE)
 		return fsck_tree((struct tree *) obj);
-	if (obj->type == commit_type)
+	if (obj->type == TYPE_COMMIT)
 		return fsck_commit((struct commit *) obj);
-	if (obj->type == tag_type)
+	if (obj->type == TYPE_TAG)
 		return fsck_tag((struct tag *) obj);
 	/* By now, parse_object() would've returned NULL instead. */
-	return objerror(obj, "unknown type '%s' (internal fsck error)", obj->type);
+	return objerror(obj, "unknown type '%d' (internal fsck error)", obj->type);
 }
 
 /*
@@ -470,7 +470,7 @@ static int fsck_cache_tree(struct cache_tree *it)
 		}
 		mark_reachable(obj, REACHABLE);
 		obj->used = 1;
-		if (obj->type != tree_type)
+		if (obj->type != TYPE_TREE)
 			err |= objerror(obj, "non-tree in cache-tree");
 	}
 	for (i = 0; i < it->subtree_nr; i++)
diff --git a/http-push.c b/http-push.c
index 2d9441ec60..ba64f8fff5 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1773,16 +1773,16 @@ static int get_delta(struct rev_info *revs, struct remote_lock *lock)
 
 		if (obj->flags & (UNINTERESTING | SEEN))
 			continue;
-		if (obj->type == tag_type) {
+		if (obj->type == TYPE_TAG) {
 			obj->flags |= SEEN;
 			p = add_object(obj, p, NULL, name);
 			continue;
 		}
-		if (obj->type == tree_type) {
+		if (obj->type == TYPE_TREE) {
 			p = process_tree((struct tree *)obj, p, NULL, name);
 			continue;
 		}
-		if (obj->type == blob_type) {
+		if (obj->type == TYPE_BLOB) {
 			p = process_blob((struct blob *)obj, p, NULL, name);
 			continue;
 		}
@@ -1949,12 +1949,12 @@ static int ref_newer(const unsigned char *new_sha1,
 	 * old.  Otherwise we require --force.
 	 */
 	o = deref_tag(parse_object(old_sha1), NULL, 0);
-	if (!o || o->type != commit_type)
+	if (!o || o->type != TYPE_COMMIT)
 		return 0;
 	old = (struct commit *) o;
 
 	o = deref_tag(parse_object(new_sha1), NULL, 0);
-	if (!o || o->type != commit_type)
+	if (!o || o->type != TYPE_COMMIT)
 		return 0;
 	new = (struct commit *) o;
 
@@ -2033,7 +2033,7 @@ static void add_remote_info_ref(struct remote_ls_ctx *ls)
 	fwrite_buffer(ref_info, 1, len, buf);
 	free(ref_info);
 
-	if (o->type == tag_type) {
+	if (o->type == TYPE_TAG) {
 		o = deref_tag(o, ls->dentry_name, 0);
 		if (o) {
 			len = strlen(ls->dentry_name) + 45;
diff --git a/name-rev.c b/name-rev.c
index bad8a53777..c29b93ea71 100644
--- a/name-rev.c
+++ b/name-rev.c
@@ -19,7 +19,7 @@ static void name_rev(struct commit *commit,
 		const char *tip_name, int merge_traversals, int generation,
 		int deref)
 {
-	struct rev_name *name = (struct rev_name *)commit->object.util;
+	struct rev_name *name = (struct rev_name *)commit->util;
 	struct commit_list *parents;
 	int parent_number = 1;
 
@@ -41,7 +41,7 @@ static void name_rev(struct commit *commit,
 
 	if (name == NULL) {
 		name = xmalloc(sizeof(rev_name));
-		commit->object.util = name;
+		commit->util = name;
 		goto copy_data;
 	} else if (name->merge_traversals > merge_traversals ||
 			(name->merge_traversals == merge_traversals &&
@@ -84,14 +84,14 @@ static int name_ref(const char *path, const unsigned char *sha1)
 	if (tags_only && strncmp(path, "refs/tags/", 10))
 		return 0;
 
-	while (o && o->type == tag_type) {
+	while (o && o->type == TYPE_TAG) {
 		struct tag *t = (struct tag *) o;
 		if (!t->tagged)
 			break; /* broken repository */
 		o = parse_object(t->tagged->sha1);
 		deref = 1;
 	}
-	if (o && o->type == commit_type) {
+	if (o && o->type == TYPE_COMMIT) {
 		struct commit *commit = (struct commit *)o;
 
 		if (!strncmp(path, "refs/heads/", 11))
@@ -108,7 +108,13 @@ static int name_ref(const char *path, const unsigned char *sha1)
 static const char* get_rev_name(struct object *o)
 {
 	static char buffer[1024];
-	struct rev_name *n = (struct rev_name *)o->util;
+	struct rev_name *n;
+	struct commit *c;
+
+	if (o->type != TYPE_COMMIT)
+		return "undefined";
+	c = (struct commit *) o;
+	n = c->util;
 	if (!n)
 		return "undefined";
 
@@ -167,7 +173,7 @@ int main(int argc, char **argv)
 		}
 
 		o = deref_tag(parse_object(sha1), *argv, 0);
-		if (!o || o->type != commit_type) {
+		if (!o || o->type != TYPE_COMMIT) {
 			fprintf(stderr, "Could not get commit for %s. Skipping.\n",
 					*argv);
 			continue;
diff --git a/object.c b/object.c
index 9adc87479b..0f70890a45 100644
--- a/object.c
+++ b/object.c
@@ -9,6 +9,10 @@ struct object **objs;
 static int nr_objs;
 int obj_allocs;
 
+const char *type_names[] = {
+	"none", "blob", "tree", "commit", "bad"
+};
+
 int track_object_refs = 0;
 
 static int hashtable_index(const unsigned char *sha1)
@@ -50,7 +54,7 @@ void created_object(const unsigned char *sha1, struct object *obj)
 
 	obj->parsed = 0;
 	memcpy(obj->sha1, sha1, 20);
-	obj->type = NULL;
+	obj->type = TYPE_NONE;
 	obj->refs = NULL;
 	obj->used = 0;
 
@@ -179,7 +183,7 @@ struct object *lookup_unknown_object(const unsigned char *sha1)
 	if (!obj) {
 		union any_object *ret = xcalloc(1, sizeof(*ret));
 		created_object(sha1, &ret->object);
-		ret->object.type = NULL;
+		ret->object.type = TYPE_NONE;
 		return &ret->object;
 	}
 	return obj;
diff --git a/object.h b/object.h
index e08afbd29f..f4ee2e55ba 100644
--- a/object.h
+++ b/object.h
@@ -12,19 +12,34 @@ struct object_refs {
 	struct object *ref[FLEX_ARRAY]; /* more */
 };
 
+#define TYPE_BITS   3
+#define FLAG_BITS  27
+
+#define TYPE_NONE   0
+#define TYPE_BLOB   1
+#define TYPE_TREE   2
+#define TYPE_COMMIT 3
+#define TYPE_TAG    4
+#define TYPE_BAD    5
+
 struct object {
 	unsigned parsed : 1;
 	unsigned used : 1;
-	unsigned int flags;
+	unsigned type : TYPE_BITS;
+	unsigned flags : FLAG_BITS;
 	unsigned char sha1[20];
-	const char *type;
 	struct object_refs *refs;
-	void *util;
 };
 
 extern int track_object_refs;
 extern int obj_allocs;
 extern struct object **objs;
+extern const char *type_names[];
+
+static inline const char *typename(unsigned int type)
+{
+	return type_names[type > TYPE_TAG ? TYPE_BAD : type];
+}
 
 /** Internal only **/
 struct object *lookup_object(const unsigned char *sha1);
diff --git a/revision.c b/revision.c
index 75c648c13c..7bff2a10b1 100644
--- a/revision.c
+++ b/revision.c
@@ -140,7 +140,7 @@ static struct commit *handle_commit(struct rev_info *revs, struct object *object
 	/*
 	 * Tag object? Look what it points to..
 	 */
-	while (object->type == tag_type) {
+	while (object->type == TYPE_TAG) {
 		struct tag *tag = (struct tag *) object;
 		if (revs->tag_objects && !(flags & UNINTERESTING))
 			add_pending_object(revs, object, tag->tag);
@@ -153,7 +153,7 @@ static struct commit *handle_commit(struct rev_info *revs, struct object *object
 	 * Commit object? Just return it, we'll do all the complex
 	 * reachability crud.
 	 */
-	if (object->type == commit_type) {
+	if (object->type == TYPE_COMMIT) {
 		struct commit *commit = (struct commit *)object;
 		if (parse_commit(commit) < 0)
 			die("unable to parse commit %s", name);
@@ -169,7 +169,7 @@ static struct commit *handle_commit(struct rev_info *revs, struct object *object
 	 * Tree object? Either mark it uniniteresting, or add it
 	 * to the list of objects to look at later..
 	 */
-	if (object->type == tree_type) {
+	if (object->type == TYPE_TREE) {
 		struct tree *tree = (struct tree *)object;
 		if (!revs->tree_objects)
 			return NULL;
@@ -184,7 +184,7 @@ static struct commit *handle_commit(struct rev_info *revs, struct object *object
 	/*
 	 * Blob object? You know the drill by now..
 	 */
-	if (object->type == blob_type) {
+	if (object->type == TYPE_BLOB) {
 		struct blob *blob = (struct blob *)object;
 		if (!revs->blob_objects)
 			return NULL;
@@ -498,11 +498,11 @@ static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 		return 0;
 	while (1) {
 		it = get_reference(revs, arg, sha1, 0);
-		if (strcmp(it->type, tag_type))
+		if (it->type != TYPE_TAG)
 			break;
 		memcpy(sha1, ((struct tag*)it)->tagged->sha1, 20);
 	}
-	if (strcmp(it->type, commit_type))
+	if (it->type != TYPE_COMMIT)
 		return 0;
 	commit = (struct commit *)it;
 	for (parents = commit->parents; parents; parents = parents->next) {
@@ -949,9 +949,11 @@ struct commit *get_revision(struct rev_info *revs)
 	}
 
 	do {
-		struct commit *commit = revs->commits->item;
+		struct commit_list *entry = revs->commits;
+		struct commit *commit = entry->item;
 
-		revs->commits = revs->commits->next;
+		revs->commits = entry->next;
+		free(entry);
 
 		/*
 		 * If we haven't done the list limiting, we need to look at
diff --git a/send-pack.c b/send-pack.c
index 409f188503..af93b11f23 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -151,12 +151,12 @@ static int ref_newer(const unsigned char *new_sha1,
 	 * old.  Otherwise we require --force.
 	 */
 	o = deref_tag(parse_object(old_sha1), NULL, 0);
-	if (!o || o->type != commit_type)
+	if (!o || o->type != TYPE_COMMIT)
 		return 0;
 	old = (struct commit *) o;
 
 	o = deref_tag(parse_object(new_sha1), NULL, 0);
-	if (!o || o->type != commit_type)
+	if (!o || o->type != TYPE_COMMIT)
 		return 0;
 	new = (struct commit *) o;
 
diff --git a/server-info.c b/server-info.c
index 05bce7da3b..0eb5132cc1 100644
--- a/server-info.c
+++ b/server-info.c
@@ -12,7 +12,7 @@ static int add_info_ref(const char *path, const unsigned char *sha1)
 	struct object *o = parse_object(sha1);
 
 	fprintf(info_ref_fp, "%s	%s\n", sha1_to_hex(sha1), path);
-	if (o->type == tag_type) {
+	if (o->type == TYPE_TAG) {
 		o = deref_tag(o, path, 0);
 		if (o)
 			fprintf(info_ref_fp, "%s	%s^{}\n",
diff --git a/sha1_name.c b/sha1_name.c
index 8fe9b7a75f..cd85d1fa0f 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -357,7 +357,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 {
 	unsigned char outer[20];
 	const char *sp;
-	const char *type_string = NULL;
+	unsigned int expected_type = 0;
 	struct object *o;
 
 	/*
@@ -381,13 +381,13 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 
 	sp++; /* beginning of type name, or closing brace for empty */
 	if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
-		type_string = commit_type;
+		expected_type = TYPE_COMMIT;
 	else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
-		type_string = tree_type;
+		expected_type = TYPE_TREE;
 	else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
-		type_string = blob_type;
+		expected_type = TYPE_BLOB;
 	else if (sp[0] == '}')
-		type_string = NULL;
+		expected_type = TYPE_NONE;
 	else
 		return -1;
 
@@ -397,7 +397,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 	o = parse_object(outer);
 	if (!o)
 		return -1;
-	if (!type_string) {
+	if (!expected_type) {
 		o = deref_tag(o, name, sp - name - 2);
 		if (!o || (!o->parsed && !parse_object(o->sha1)))
 			return -1;
@@ -412,18 +412,18 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 		while (1) {
 			if (!o || (!o->parsed && !parse_object(o->sha1)))
 				return -1;
-			if (o->type == type_string) {
+			if (o->type == expected_type) {
 				memcpy(sha1, o->sha1, 20);
 				return 0;
 			}
-			if (o->type == tag_type)
+			if (o->type == TYPE_TAG)
 				o = ((struct tag*) o)->tagged;
-			else if (o->type == commit_type)
+			else if (o->type == TYPE_COMMIT)
 				o = &(((struct commit *) o)->tree->object);
 			else
 				return error("%.*s: expected %s type, but the object dereferences to %s type",
-					     len, name, type_string,
-					     o->type);
+					     len, name, typename(expected_type),
+					     typename(o->type));
 			if (!o->parsed)
 				parse_object(o->sha1);
 		}
diff --git a/tag.c b/tag.c
index f390ee7030..9191333270 100644
--- a/tag.c
+++ b/tag.c
@@ -5,7 +5,7 @@ const char *tag_type = "tag";
 
 struct object *deref_tag(struct object *o, const char *warn, int warnlen)
 {
-	while (o && o->type == tag_type)
+	while (o && o->type == TYPE_TAG)
 		o = parse_object(((struct tag *)o)->tagged->sha1);
 	if (!o && warn) {
 		if (!warnlen)
@@ -21,14 +21,14 @@ struct tag *lookup_tag(const unsigned char *sha1)
         if (!obj) {
                 struct tag *ret = xcalloc(1, sizeof(struct tag));
                 created_object(sha1, &ret->object);
-                ret->object.type = tag_type;
+                ret->object.type = TYPE_TAG;
                 return ret;
         }
 	if (!obj->type)
-		obj->type = tag_type;
-        if (obj->type != tag_type) {
-                error("Object %s is a %s, not a tree", 
-                      sha1_to_hex(sha1), obj->type);
+		obj->type = TYPE_TAG;
+        if (obj->type != TYPE_TAG) {
+                error("Object %s is a %s, not a tree",
+                      sha1_to_hex(sha1), typename(obj->type));
                 return NULL;
         }
         return (struct tag *) obj;
diff --git a/tree.c b/tree.c
index 9bbe2da37b..64422fd27e 100644
--- a/tree.c
+++ b/tree.c
@@ -131,14 +131,14 @@ struct tree *lookup_tree(const unsigned char *sha1)
 	if (!obj) {
 		struct tree *ret = xcalloc(1, sizeof(struct tree));
 		created_object(sha1, &ret->object);
-		ret->object.type = tree_type;
+		ret->object.type = TYPE_TREE;
 		return ret;
 	}
 	if (!obj->type)
-		obj->type = tree_type;
-	if (obj->type != tree_type) {
-		error("Object %s is a %s, not a tree", 
-		      sha1_to_hex(sha1), obj->type);
+		obj->type = TYPE_TREE;
+	if (obj->type != TYPE_TREE) {
+		error("Object %s is a %s, not a tree",
+		      sha1_to_hex(sha1), typename(obj->type));
 		return NULL;
 	}
 	return (struct tree *) obj;
@@ -216,11 +216,11 @@ struct tree *parse_tree_indirect(const unsigned char *sha1)
 	do {
 		if (!obj)
 			return NULL;
-		if (obj->type == tree_type)
+		if (obj->type == TYPE_TREE)
 			return (struct tree *) obj;
-		else if (obj->type == commit_type)
+		else if (obj->type == TYPE_COMMIT)
 			obj = &(((struct commit *) obj)->tree->object);
-		else if (obj->type == tag_type)
+		else if (obj->type == TYPE_TAG)
 			obj = ((struct tag *) obj)->tagged;
 		else
 			return NULL;
diff --git a/upload-pack.c b/upload-pack.c
index 47560c9527..979e58306e 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -105,7 +105,7 @@ static int got_sha1(char *hex, unsigned char *sha1)
 			o = parse_object(sha1);
 		if (!o)
 			die("oops (%s)", sha1_to_hex(sha1));
-		if (o->type == commit_type) {
+		if (o->type == TYPE_COMMIT) {
 			struct commit_list *parents;
 			if (o->flags & THEY_HAVE)
 				return 0;
@@ -234,7 +234,7 @@ static int send_ref(const char *refname, const unsigned char *sha1)
 		o->flags |= OUR_REF;
 		nr_our_refs++;
 	}
-	if (o->type == tag_type) {
+	if (o->type == TYPE_TAG) {
 		o = deref_tag(o, refname, 0);
 		packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 	}