Improves gtest's failure messages. In particulars, char pointers and

char arrays are not escapped properly.

include/gtest/gtest.h

@@ -1291,24 +1291,101 @@ GTEST_API_ void InitGoogleTest(int* argc, wchar_t** argv);
 
 namespace internal {
 
+// FormatForComparison<ToPrint, OtherOperand>::Format(value) formats a
+// value of type ToPrint that is an operand of a comparison assertion
+// (e.g. ASSERT_EQ).  OtherOperand is the type of the other operand in
+// the comparison, and is used to help determine the best way to
+// format the value.  In particular, when the value is a C string
+// (char pointer) and the other operand is an STL string object, we
+// want to format the C string as a string, since we know it is
+// compared by value with the string object.  If the value is a char
+// pointer but the other operand is not an STL string object, we don't
+// know whether the pointer is supposed to point to a NUL-terminated
+// string, and thus want to print it as a pointer to be safe.
+//
+// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
+
+// The default case.
+template <typename ToPrint, typename OtherOperand>
+class FormatForComparison {
+ public:
+  static ::std::string Format(const ToPrint& value) {
+    return ::testing::PrintToString(value);
+  }
+};
+
+// Array.
+template <typename ToPrint, size_t N, typename OtherOperand>
+class FormatForComparison<ToPrint[N], OtherOperand> {
+ public:
+  static ::std::string Format(const ToPrint* value) {
+    return FormatForComparison<const ToPrint*, OtherOperand>::Format(value);
+  }
+};
+
+// By default, print C string as pointers to be safe, as we don't know
+// whether they actually point to a NUL-terminated string.
+
+#define GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(CharType)                \
+  template <typename OtherOperand>                                      \
+  class FormatForComparison<CharType*, OtherOperand> {                  \
+   public:                                                              \
+    static ::std::string Format(CharType* value) {                      \
+      return ::testing::PrintToString(static_cast<const void*>(value)); \
+    }                                                                   \
+  }
+
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(char);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(wchar_t);
+GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const wchar_t);
+
+#undef GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_
+
+// If a C string is compared with an STL string object, we know it's meant
+// to point to a NUL-terminated string, and thus can print it as a string.
+
+#define GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(CharType, OtherStringType) \
+  template <>                                                           \
+  class FormatForComparison<CharType*, OtherStringType> {               \
+   public:                                                              \
+    static ::std::string Format(CharType* value) {                      \
+      return ::testing::PrintToString(value);                           \
+    }                                                                   \
+  }
+
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::std::string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::std::string);
+
+#if GTEST_HAS_GLOBAL_STRING
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::string);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::string);
+#endif
+
+#if GTEST_HAS_GLOBAL_WSTRING
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(wchar_t, ::wstring);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const wchar_t, ::wstring);
+#endif
+
+#if GTEST_HAS_STD_WSTRING
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(wchar_t, ::std::wstring);
+GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const wchar_t, ::std::wstring);
+#endif
+
+#undef GTEST_IMPL_FORMAT_C_STRING_AS_STRING_
+
 // Formats a comparison assertion (e.g. ASSERT_EQ, EXPECT_LT, and etc)
 // operand to be used in a failure message.  The type (but not value)
 // of the other operand may affect the format.  This allows us to
 // print a char* as a raw pointer when it is compared against another
-// char*, and print it as a C string when it is compared against an
-// std::string object, for example.
-//
-// The default implementation ignores the type of the other operand.
-// Some specialized versions are used to handle formatting wide or
-// narrow C strings.
+// char* or void*, and print it as a C string when it is compared
+// against an std::string object, for example.
 //
 // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
 template <typename T1, typename T2>
 String FormatForComparisonFailureMessage(const T1& value,
                                          const T2& /* other_operand */) {
-  // C++Builder compiles this incorrectly if the namespace isn't explicitly
-  // given.
-  return ::testing::PrintToString(value);
+  return FormatForComparison<T1, T2>::Format(value);
 }
 
 // The helper function for {ASSERT|EXPECT}_EQ.
@@ -1320,7 +1397,7 @@ AssertionResult CmpHelperEQ(const char* expected_expression,
 #ifdef _MSC_VER
 # pragma warning(push)          // Saves the current warning state.
 # pragma warning(disable:4389)  // Temporarily disables warning on
-                               // signed/unsigned mismatch.
+                                // signed/unsigned mismatch.
 #endif
 
   if (expected == actual) {