Merge pull request #2837 from inazarenko:duck_type_protos

PiperOrigin-RevId: 336087297

2 files changed, 30 insertions, 6 deletions

diff --git a/googletest/include/gtest/gtest-printers.h b/googletest/include/gtest/gtest-printers.h
index f24512a9..99129a53 100644
--- a/googletest/include/gtest/gtest-printers.h
+++ b/googletest/include/gtest/gtest-printers.h
@@ -235,8 +235,9 @@ struct ProtobufPrinter {
   // DebugString() for better readability.
   static const size_t kProtobufOneLinerMaxLength = 50;
 
-  template <typename T, typename = typename std::enable_if<
-                            internal::IsAProtocolMessage<T>::value>::type>
+  template <typename T,
+            typename = typename std::enable_if<
+                internal::HasDebugStringAndShortDebugString<T>::value>::type>
   static void PrintValue(const T& value, ::std::ostream* os) {
     std::string pretty_str = value.ShortDebugString();
     if (pretty_str.length() > kProtobufOneLinerMaxLength) {
diff --git a/googletest/include/gtest/internal/gtest-internal.h b/googletest/include/gtest/internal/gtest-internal.h
index 233724cc..bd4e4198 100644
--- a/googletest/include/gtest/internal/gtest-internal.h
+++ b/googletest/include/gtest/internal/gtest-internal.h
@@ -892,11 +892,34 @@ class GTEST_API_ Random {
 #define GTEST_REMOVE_REFERENCE_AND_CONST_(T) \
   typename std::remove_const<typename std::remove_reference<T>::type>::type
 
-// IsAProtocolMessage<T>::value is a compile-time bool constant that's
-// true if and only if T is type proto2::MessageLite or a subclass of it.
+// HasDebugStringAndShortDebugString<T>::value is a compile-time bool constant
+// that's true if and only if T has methods DebugString() and ShortDebugString()
+// that return std::string.
 template <typename T>
-struct IsAProtocolMessage
-    : public std::is_convertible<const T*, const ::proto2::MessageLite*> {};
+class HasDebugStringAndShortDebugString {
+ private:
+  template <typename C>
+  static constexpr auto CheckDebugString(C*) -> typename std::is_same<
+      std::string, decltype(std::declval<const C>().DebugString())>::type;
+  template <typename>
+  static constexpr std::false_type CheckDebugString(...);
+
+  template <typename C>
+  static constexpr auto CheckShortDebugString(C*) -> typename std::is_same<
+      std::string, decltype(std::declval<const C>().ShortDebugString())>::type;
+  template <typename>
+  static constexpr std::false_type CheckShortDebugString(...);
+
+  using HasDebugStringType = decltype(CheckDebugString<T>(nullptr));
+  using HasShortDebugStringType = decltype(CheckShortDebugString<T>(nullptr));
+
+ public:
+  static constexpr bool value =
+      HasDebugStringType::value && HasShortDebugStringType::value;
+};
+
+template <typename T>
+constexpr bool HasDebugStringAndShortDebugString<T>::value;
 
 // When the compiler sees expression IsContainerTest<C>(0), if C is an
 // STL-style container class, the first overload of IsContainerTest