Add support for enum types with AbslStringify

PiperOrigin-RevId: 487394692
Change-Id: I55e9b57055483dc921e9773c3643ea9be4f9bdf6

1 files changed, 8 insertions, 2 deletions

diff --git a/absl/strings/internal/str_format/arg.h b/absl/strings/internal/str_format/arg.h
index b3e4ff15..bc4cde96 100644
--- a/absl/strings/internal/str_format/arg.h
+++ b/absl/strings/internal/str_format/arg.h
@@ -18,6 +18,7 @@
 #include <string.h>
 #include <wchar.h>
 
+#include <algorithm>
 #include <cstdio>
 #include <iomanip>
 #include <limits>
@@ -25,10 +26,12 @@
 #include <sstream>
 #include <string>
 #include <type_traits>
+#include <utility>
 
 #include "absl/base/port.h"
 #include "absl/meta/type_traits.h"
 #include "absl/numeric/int128.h"
+#include "absl/strings/internal/has_absl_stringify.h"
 #include "absl/strings/internal/str_format/extension.h"
 #include "absl/strings/string_view.h"
 
@@ -271,7 +274,8 @@ IntegralConvertResult FormatConvertImpl(T v, FormatConversionSpecImpl conv,
 // FormatArgImpl will use the underlying Convert functions instead.
 template <typename T>
 typename std::enable_if<std::is_enum<T>::value &&
-                            !HasUserDefinedConvert<T>::value,
+                            !HasUserDefinedConvert<T>::value &&
+                            !strings_internal::HasAbslStringify<T>::value,
                         IntegralConvertResult>::type
 FormatConvertImpl(T v, FormatConversionSpecImpl conv, FormatSinkImpl* sink);
 
@@ -384,7 +388,8 @@ class FormatArgImpl {
   template <typename T, typename = void>
   struct DecayType {
     static constexpr bool kHasUserDefined =
-        str_format_internal::HasUserDefinedConvert<T>::value;
+        str_format_internal::HasUserDefinedConvert<T>::value ||
+        strings_internal::HasAbslStringify<T>::value;
     using type = typename std::conditional<
         !kHasUserDefined && std::is_convertible<T, const char*>::value,
         const char*,
@@ -396,6 +401,7 @@ class FormatArgImpl {
   struct DecayType<T,
                    typename std::enable_if<
                        !str_format_internal::HasUserDefinedConvert<T>::value &&
+                       !strings_internal::HasAbslStringify<T>::value &&
                        std::is_enum<T>::value>::type> {
     using type = typename std::underlying_type<T>::type;
   };