diff --git a/builtin/branch.c b/builtin/branch.c
index 15232c4a42..1d41251a9a 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -618,7 +618,7 @@ static int edit_branch_description(const char *branch_name)
 		    "  %s\n"
 		    "Lines starting with '%c' will be stripped.\n",
 		    branch_name, comment_line_char);
-	write_file(git_path(edit_description), "%s", buf.buf);
+	write_file_buf(git_path(edit_description), buf.buf, buf.len);
 	strbuf_reset(&buf);
 	if (launch_editor(git_path(edit_description), &buf, NULL)) {
 		strbuf_release(&buf);