From bc9518512266b994ad2af2228bc5672df8ea546b Mon Sep 17 00:00:00 2001
From: "Paul J. Davis" <paul.davis@tiledb.com>
Date: Fri, 15 Sep 2023 09:35:41 -0500
Subject: [PATCH] Fix UBSAN error in the Enumeration CPP API

Apparently one of our many build chains decided that faking a default
parameter for a `tiledb_datatype_t` is undefined behavior, which, fair
enough. The fix should be to just use a std::optional instead.
---
 tiledb/sm/cpp_api/enumeration_experimental.h | 22 +++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/tiledb/sm/cpp_api/enumeration_experimental.h b/tiledb/sm/cpp_api/enumeration_experimental.h
index af4b8aa1bf80..fc512618cf9d 100644
--- a/tiledb/sm/cpp_api/enumeration_experimental.h
+++ b/tiledb/sm/cpp_api/enumeration_experimental.h
@@ -239,17 +239,20 @@ class Enumeration {
       const std::string& name,
       std::vector<T>& values,
       bool ordered = false,
-      tiledb_datatype_t type = static_cast<tiledb_datatype_t>(255)) {
+      std::optional<tiledb_datatype_t> type = std::nullopt) {
     using DataT = impl::TypeHandler<T>;
 
-    if (type == static_cast<tiledb_datatype_t>(255)) {
-      type = DataT::tiledb_type;
+    tiledb_datatype_t dtype;
+    if (type.has_value()) {
+      dtype = type.value();
+    } else {
+      dtype = DataT::tiledb_type;
     }
 
     return create(
         ctx,
         name,
-        type,
+        dtype,
         DataT::tiledb_num,
         ordered,
         values.data(),
@@ -275,13 +278,16 @@ class Enumeration {
       const std::string& name,
       std::vector<std::basic_string<T>>& values,
       bool ordered = false,
-      tiledb_datatype_t type = static_cast<tiledb_datatype_t>(255)) {
+      std::optional<tiledb_datatype_t> type = std::nullopt) {
     using DataT = impl::TypeHandler<T>;
     static_assert(
         DataT::tiledb_num == 1, "Enumeration string values cannot be compound");
 
-    if (type == static_cast<tiledb_datatype_t>(255)) {
-      type = DataT::tiledb_type;
+    tiledb_datatype_t dtype;
+    if (type.has_value()) {
+      dtype = type.value();
+    } else {
+      dtype = DataT::tiledb_type;
     }
 
     uint64_t total_size = 0;
@@ -303,7 +309,7 @@ class Enumeration {
     return create(
         ctx,
         name,
-        type,
+        dtype,
         TILEDB_VAR_NUM,
         ordered,
         data.data(),