diff --git a/bundle.c b/bundle.c
index fa67057e60f..2e2dbd50efb 100644
--- a/bundle.c
+++ b/bundle.c
@@ -235,33 +235,50 @@ out:
 	return result;
 }
 
-int create_bundle(struct bundle_header *header, const char *path,
-		  int argc, const char **argv)
+static int write_pack_data(int bundle_fd, struct lock_file *lock, struct rev_info *revs)
+{
+	struct child_process pack_objects = CHILD_PROCESS_INIT;
+	int i;
+
+	argv_array_pushl(&pack_objects.args,
+			 "pack-objects", "--all-progress-implied",
+			 "--stdout", "--thin", "--delta-base-offset",
+			 NULL);
+	pack_objects.in = -1;
+	pack_objects.out = bundle_fd;
+	pack_objects.git_cmd = 1;
+	if (start_command(&pack_objects))
+		return error(_("Could not spawn pack-objects"));
+
+	/*
+	 * start_command closed bundle_fd if it was > 1
+	 * so set the lock fd to -1 so commit_lock_file()
+	 * won't fail trying to close it.
+	 */
+	lock->fd = -1;
+
+	for (i = 0; i < revs->pending.nr; i++) {
+		struct object *object = revs->pending.objects[i].item;
+		if (object->flags & UNINTERESTING)
+			write_or_die(pack_objects.in, "^", 1);
+		write_or_die(pack_objects.in, sha1_to_hex(object->sha1), 40);
+		write_or_die(pack_objects.in, "\n", 1);
+	}
+	close(pack_objects.in);
+	if (finish_command(&pack_objects))
+		return error(_("pack-objects died"));
+	return 0;
+}
+
+static int compute_and_write_prerequisites(int bundle_fd,
+					   struct rev_info *revs,
+					   int argc, const char **argv)
 {
-	static struct lock_file lock;
-	int bundle_fd = -1;
-	int bundle_to_stdout;
-	int i, ref_count = 0;
-	struct strbuf buf = STRBUF_INIT;
-	struct rev_info revs;
 	struct child_process rls = CHILD_PROCESS_INIT;
+	struct strbuf buf = STRBUF_INIT;
 	FILE *rls_fout;
+	int i;
 
-	bundle_to_stdout = !strcmp(path, "-");
-	if (bundle_to_stdout)
-		bundle_fd = 1;
-	else
-		bundle_fd = hold_lock_file_for_update(&lock, path,
-						      LOCK_DIE_ON_ERROR);
-
-	/* write signature */
-	write_or_die(bundle_fd, bundle_signature, strlen(bundle_signature));
-
-	/* init revs to list objects for pack-objects later */
-	save_commit_buffer = 0;
-	init_revisions(&revs, NULL);
-
-	/* write prerequisites */
 	argv_array_pushl(&rls.args,
 			 "rev-list", "--boundary", "--pretty=oneline",
 			 NULL);
@@ -279,7 +296,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 			if (!get_sha1_hex(buf.buf + 1, sha1)) {
 				struct object *object = parse_object_or_die(sha1, buf.buf);
 				object->flags |= UNINTERESTING;
-				add_pending_object(&revs, object, buf.buf);
+				add_pending_object(revs, object, buf.buf);
 			}
 		} else if (!get_sha1_hex(buf.buf, sha1)) {
 			struct object *object = parse_object_or_die(sha1, buf.buf);
@@ -290,17 +307,25 @@ int create_bundle(struct bundle_header *header, const char *path,
 	fclose(rls_fout);
 	if (finish_command(&rls))
 		return error(_("rev-list died"));
+	return 0;
+}
 
-	/* write references */
-	argc = setup_revisions(argc, argv, &revs, NULL);
+/*
+ * Write out bundle refs based on the tips already
+ * parsed into revs.pending. As a side effect, may
+ * manipulate revs.pending to include additional
+ * necessary objects (like tags).
+ *
+ * Returns the number of refs written, or negative
+ * on error.
+ */
+static int write_bundle_refs(int bundle_fd, struct rev_info *revs)
+{
+	int i;
+	int ref_count = 0;
 
-	if (argc > 1)
-		return error(_("unrecognized argument: %s"), argv[1]);
-
-	object_array_remove_duplicates(&revs.pending);
-
-	for (i = 0; i < revs.pending.nr; i++) {
-		struct object_array_entry *e = revs.pending.objects + i;
+	for (i = 0; i < revs->pending.nr; i++) {
+		struct object_array_entry *e = revs->pending.objects + i;
 		unsigned char sha1[20];
 		char *ref;
 		const char *display_ref;
@@ -315,7 +340,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 		display_ref = (flag & REF_ISSYMREF) ? e->name : ref;
 
 		if (e->item->type == OBJ_TAG &&
-				!is_tag_in_date_range(e->item, &revs)) {
+				!is_tag_in_date_range(e->item, revs)) {
 			e->item->flags |= UNINTERESTING;
 			continue;
 		}
@@ -361,7 +386,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 				 */
 				obj = parse_object_or_die(sha1, e->name);
 				obj->flags |= SHOWN;
-				add_pending_object(&revs, obj, e->name);
+				add_pending_object(revs, obj, e->name);
 			}
 			free(ref);
 			continue;
@@ -374,41 +399,56 @@ int create_bundle(struct bundle_header *header, const char *path,
 		write_or_die(bundle_fd, "\n", 1);
 		free(ref);
 	}
-	if (!ref_count)
-		die(_("Refusing to create empty bundle."));
 
 	/* end header */
 	write_or_die(bundle_fd, "\n", 1);
+	return ref_count;
+}
+
+int create_bundle(struct bundle_header *header, const char *path,
+		  int argc, const char **argv)
+{
+	static struct lock_file lock;
+	int bundle_fd = -1;
+	int bundle_to_stdout;
+	int ref_count = 0;
+	struct rev_info revs;
+
+	bundle_to_stdout = !strcmp(path, "-");
+	if (bundle_to_stdout)
+		bundle_fd = 1;
+	else
+		bundle_fd = hold_lock_file_for_update(&lock, path,
+						      LOCK_DIE_ON_ERROR);
+
+	/* write signature */
+	write_or_die(bundle_fd, bundle_signature, strlen(bundle_signature));
+
+	/* init revs to list objects for pack-objects later */
+	save_commit_buffer = 0;
+	init_revisions(&revs, NULL);
+
+	/* write prerequisites */
+	if (compute_and_write_prerequisites(bundle_fd, &revs, argc, argv))
+		return -1;
+
+	argc = setup_revisions(argc, argv, &revs, NULL);
+
+	if (argc > 1)
+		return error(_("unrecognized argument: %s"), argv[1]);
+
+	object_array_remove_duplicates(&revs.pending);
+
+	ref_count = write_bundle_refs(bundle_fd, &revs);
+	if (!ref_count)
+		die(_("Refusing to create empty bundle."));
+	else if (ref_count < 0)
+		return -1;
 
 	/* write pack */
-	memset(&rls, 0, sizeof(rls));
-	argv_array_pushl(&rls.args,
-			 "pack-objects", "--all-progress-implied",
-			 "--stdout", "--thin", "--delta-base-offset",
-			 NULL);
-	rls.in = -1;
-	rls.out = bundle_fd;
-	rls.git_cmd = 1;
-	if (start_command(&rls))
-		return error(_("Could not spawn pack-objects"));
+	if (write_pack_data(bundle_fd, &lock, &revs))
+		return -1;
 
-	/*
-	 * start_command closed bundle_fd if it was > 1
-	 * so set the lock fd to -1 so commit_lock_file()
-	 * won't fail trying to close it.
-	 */
-	lock.fd = -1;
-
-	for (i = 0; i < revs.pending.nr; i++) {
-		struct object *object = revs.pending.objects[i].item;
-		if (object->flags & UNINTERESTING)
-			write_or_die(rls.in, "^", 1);
-		write_or_die(rls.in, sha1_to_hex(object->sha1), 40);
-		write_or_die(rls.in, "\n", 1);
-	}
-	close(rls.in);
-	if (finish_command(&rls))
-		return error(_("pack-objects died"));
 	if (!bundle_to_stdout) {
 		if (commit_lock_file(&lock))
 			die_errno(_("cannot create '%s'"), path);
diff --git a/column.c b/column.c
index 8082a944fd6..786abe62b0b 100644
--- a/column.c
+++ b/column.c
@@ -374,7 +374,7 @@ int run_column_filter(int colopts, const struct column_options *opts)
 	if (fd_out != -1)
 		return -1;
 
-	memset(&column_process, 0, sizeof(column_process));
+	child_process_init(&column_process);
 	argv = &column_process.args;
 
 	argv_array_push(argv, "column");
diff --git a/trailer.c b/trailer.c
index 85145665640..7ff036cb84d 100644
--- a/trailer.c
+++ b/trailer.c
@@ -237,7 +237,7 @@ static const char *apply_command(const char *command, const char *arg)
 		strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 
 	argv[0] = cmd.buf;
-	memset(&cp, 0, sizeof(cp));
+	child_process_init(&cp);
 	cp.argv = argv;
 	cp.env = local_repo_env;
 	cp.no_stdin = 1;
diff --git a/transport-helper.c b/transport-helper.c
index 6cd9dd1f9fe..0224687a231 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -414,7 +414,7 @@ static int get_exporter(struct transport *transport,
 	struct child_process *helper = get_helper(transport);
 	int i;
 
-	memset(fastexport, 0, sizeof(*fastexport));
+	child_process_init(fastexport);
 
 	/* we need to duplicate helper->in because we want to use it after
 	 * fastexport is done with it. */