Use STL capabilities to choose GTEST_HAS_STD_WSTRING default

If the standard library claims not to support wide character strings, disable `GTEST_HAS_STD_WSTRING` and disallow users overriding it. If the standard library implementation can't be recognized, fall back to using the existing list of OSes with a known lack of support.

PiperOrigin-RevId: 964237076
Change-Id: I906f296259f8f17099990d51447a0d0d04dead66

README.md

@@ -8,12 +8,12 @@ Our documentation is now live on GitHub Pages at
 https://google.github.io/googletest/. We recommend browsing the documentation on
 GitHub Pages rather than directly in the repository.
 
-#### Release 1.17.0
+#### Release 1.18.0
 
-[Release 1.17.0](https://github.com/google/googletest/releases/tag/v1.17.0) is
+[Release 1.18.0](https://github.com/google/googletest/releases/tag/v1.18.0) is
 now available.
 
-The 1.17.x branch
+The 1.18.x branch
 [requires at least C++17](https://opensource.google/documentation/policies/cplusplus-support#c_language_standard).
 
 #### Continuous Integration

docs/quickstart-bazel.md

@@ -48,7 +48,7 @@ with the following content:
 
 # Choose the most recent version available at
 # https://registry.bazel.build/modules/googletest
-bazel_dep(name = "googletest", version = "1.17.0")
+bazel_dep(name = "googletest", version = "1.18.0")
 ```
 
 Now you're ready to build C++ code that uses GoogleTest.

googlemock/include/gmock/gmock-actions.h

@@ -940,7 +940,7 @@ class [[nodiscard]] ReturnAction final {
                 std::is_convertible<R, U>,        //
                 std::is_move_constructible<U>>::value>::type>
   operator OnceAction<U(Args...)>() && {  // NOLINT
-    return Impl<U>(std::move(value_));
+    return OnceImpl<U>(std::move(value_));
   }
 
   template <typename U, typename... Args,
@@ -959,13 +959,6 @@ class [[nodiscard]] ReturnAction final {
   template <typename U>
   class Impl final {
    public:
-    // The constructor used when the return value is allowed to move from the
-    // input value (i.e. we are converting to OnceAction).
-    explicit Impl(R&& input_value)
-        : state_(new State(std::move(input_value))) {}
-
-    // The constructor used when the return value is not allowed to move from
-    // the input value (i.e. we are converting to Action).
     explicit Impl(const R& input_value) : state_(new State(input_value)) {}
 
     U operator()() && { return std::move(state_->value); }
@@ -996,18 +989,6 @@ class [[nodiscard]] ReturnAction final {
             // explicit constructor from R.
             value(ImplicitCast_<U>(internal::as_const(input_value))) {}
 
-      // As above, but for the case where we're moving from the ReturnAction
-      // object because it's being used as a OnceAction.
-      explicit State(R&& input_value_in)
-          : input_value(std::move(input_value_in)),
-            // For the same reason as above we make an implicit conversion to U
-            // before initializing the value.
-            //
-            // Unlike above we provide the input value as an rvalue to the
-            // implicit conversion because this is a OnceAction: it's fine if it
-            // wants to consume the input value.
-            value(ImplicitCast_<U>(std::move(input_value))) {}
-
       // A copy of the value originally provided by the user. We retain this in
       // addition to the value of the mock function's result type below in case
       // the latter is a reference-like type. See the std::string_view example
@@ -1085,6 +1066,23 @@ class [[nodiscard]] ReturnAction final {
     const std::shared_ptr<State> state_;
   };
 
+  // Implements the Return(x) action for a mock function that returns type U,
+  // but is only executed at most once. This allows us to store the original
+  // value and move construct the return value type on the first (and only)
+  // call.
+  template <typename U>
+  class OnceImpl final {
+   public:
+    explicit OnceImpl(R&& input_value)
+        : input_value_(new R(std::move(input_value))) {}
+
+    U operator()() && { return std::move(*input_value_); }
+
+   private:
+    // Move the input value to the heap and make it copyable.
+    const std::shared_ptr<R> input_value_;
+  };
+
   R value_;
 };
 

googletest/README.md

@@ -25,7 +25,7 @@ When building GoogleTest as a standalone project, the typical workflow starts
 with
 
 ```
-git clone https://github.com/google/googletest.git -b v1.17.0
+git clone https://github.com/google/googletest.git -b v1.18.0
 cd googletest        # Main directory of the cloned repository.
 mkdir build          # Create a directory to hold the build output.
 cd build

googletest/include/gtest/gtest-printers.h

@@ -1173,15 +1173,12 @@ class [[nodiscard]] UniversalTersePrinter<const wchar_t*> {
     }
   }
 };
-#endif
 
 template <>
-class [[nodiscard]] UniversalTersePrinter<wchar_t*> {
- public:
-  static void Print(wchar_t* str, ::std::ostream* os) {
-    UniversalTersePrinter<const wchar_t*>::Print(str, os);
-  }
-};
+class [[nodiscard]] UniversalTersePrinter<wchar_t*>
+    : public UniversalTersePrinter<const wchar_t*> {};
+
+#endif  // GTEST_HAS_STD_WSTRING
 
 template <typename T>
 void UniversalTersePrint(const T& value, ::std::ostream* os) {

googletest/include/gtest/internal/gtest-port.h

@@ -500,22 +500,71 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 #endif  // defined(_MSC_VER) || defined(__BORLANDC__)
 #endif  // GTEST_HAS_EXCEPTIONS
 
-#ifndef GTEST_HAS_STD_WSTRING
-// The user didn't tell us whether ::std::wstring is available, so we need
-// to figure it out.
-// Cygwin 1.7 and below doesn't support ::std::wstring.
-// Solaris' libc++ doesn't support it either.  Android has
-// no support for it at least as recent as Froyo (2.2).
-#if (!(defined(GTEST_OS_LINUX_ANDROID) || defined(GTEST_OS_CYGWIN) || \
-       defined(GTEST_OS_SOLARIS) || defined(GTEST_OS_HAIKU) ||        \
-       defined(GTEST_OS_ESP32) || defined(GTEST_OS_ESP8266) ||        \
-       defined(GTEST_OS_XTENSA) || defined(GTEST_OS_QURT) ||          \
-       defined(GTEST_OS_NXP_QN9090) || defined(GTEST_OS_NRF52)))
-#define GTEST_HAS_STD_WSTRING 1
+// 1. Calculate default GTEST_HAS_STD_WSTRING values based on STL capabilities.
+#if defined(_MSVC_STL_VERSION)
+// Microsoft's STL implementation always supports ::std::wstring.
+#define GTEST_HAS_STD_WSTRING_DEFAULT 1
+
+#elif defined(_LIBCPP_VERSION)
+// Modern libc++ always defines _LIBCPP_HAS_WIDE_CHARACTERS; its value
+// determines whether wide characters are supported.
+// Older libc++ omits a definition for _LIBCPP_HAS_NO_WIDE_CHARACTERS when wide
+// characters are supported.
+#if (defined(_LIBCPP_HAS_WIDE_CHARACTERS) && !_LIBCPP_HAS_WIDE_CHARACTERS) || \
+    defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#define GTEST_HAS_STD_WSTRING_DEFAULT 0
 #else
-#define GTEST_HAS_STD_WSTRING 0
+#define GTEST_HAS_STD_WSTRING_DEFAULT 1
+#endif
+
+#elif defined(__GLIBCXX__)
+#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_WCHAR_T
+#define GTEST_HAS_STD_WSTRING_DEFAULT 1
+#else
+#define GTEST_HAS_STD_WSTRING_DEFAULT 0
+#endif
+
+#else
+// Unknown standard library implementation; fall back looking at the OS.
+//
+// Always let the user override the defaults in this case; they might have more
+// information about what's supported than we do.
+#if defined(GTEST_OS_LINUX_ANDROID)
+// Android started supporting std::wstring with API Level 21 (Lollipop).
+#define GTEST_HAS_STD_WSTRING_DEFAULT (__ANDROID_API__ >= 21)
+// The following platforms are known not to support ::std::wstring; assume it's
+// supported on all others.
+//
+// Cygwin 1.7 and below doesn't support ::std::wstring.
+// Solaris' libc++ doesn't support it either.
+#elif defined(GTEST_OS_CYGWIN) || defined(GTEST_OS_SOLARIS) || \
+    defined(GTEST_OS_HAIKU) || defined(GTEST_OS_ESP32) ||      \
+    defined(GTEST_OS_ESP8266) || defined(GTEST_OS_XTENSA) ||   \
+    defined(GTEST_OS_QURT) || defined(GTEST_OS_NXP_QN9090) ||  \
+    defined(GTEST_OS_NRF52)
+#define GTEST_HAS_STD_WSTRING_DEFAULT 0
+#else
+#define GTEST_HAS_STD_WSTRING_DEFAULT 1
+#endif
+#endif
+
+// 2. Validate explicit user overrides (if user passed -DGTEST_HAS_*=1) against
+//    what the standard library implementation tells us it supports.
+#if defined(GTEST_HAS_STD_WSTRING) && GTEST_HAS_STD_WSTRING
+#if defined(_LIBCPP_VERSION) &&                                                \
+    ((defined(_LIBCPP_HAS_WIDE_CHARACTERS) && !_LIBCPP_HAS_WIDE_CHARACTERS) || \
+     defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS))
+#error Cannot explicitly enable GTEST_HAS_STD_WSTRING without libc++ wide character support.
+#elif defined(__GLIBCXX__) && \
+    !(defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_WCHAR_T)
+#error Cannot explicitly enable GTEST_HAS_STD_WSTRING without libstdc++ wide character support.
+#endif
+#endif
+
+// 3. Set final values if not explicitly overridden by user
+#if !defined(GTEST_HAS_STD_WSTRING)
+#define GTEST_HAS_STD_WSTRING GTEST_HAS_STD_WSTRING_DEFAULT
 #endif
-#endif  // GTEST_HAS_STD_WSTRING
 
 #ifndef GTEST_HAS_FILE_SYSTEM
 // Most platforms support a file system.

googletest/src/gtest-printers.cc

@@ -50,6 +50,7 @@
 #include <iomanip>
 #include <ios>
 #include <ostream>  // NOLINT
+#include <string>
 #include <string_view>
 #include <type_traits>
 
@@ -422,6 +423,28 @@ void UniversalPrintArray(const wchar_t* begin, size_t len, ostream* os) {
 
 namespace {
 
+template <typename Char>
+size_t GetLength(const Char* s) {
+  return std::char_traits<Char>::length(s);
+}
+
+#if !GTEST_HAS_STD_WSTRING
+
+// If GTEST_HAS_STD_WSTRING is unset because the standard library has disabled
+// wide character support, std::char_traits<wchar_t> won't be defined, which
+// will cause a compile error, even if user code never actually could print a
+// wide cstring. In that case, instead use `wcslen` directly.
+//
+// If `libc` _also_ lacks wide character support, this (and a bunch of other
+// calls to wc functions) will fail to link, but only if user code actually
+// uses them.
+template <>
+size_t GetLength<wchar_t>(const wchar_t* s) {
+  return wcslen(s);
+}
+
+#endif  // GTEST_HAS_STD_WSTRING
+
 // Prints a null-terminated C-style string to the ostream.
 template <typename Char>
 void PrintCStringTo(const Char* s, ostream* os) {
@@ -429,7 +452,7 @@ void PrintCStringTo(const Char* s, ostream* os) {
     *os << "NULL";
   } else {
     *os << ImplicitCast_<const void*>(s) << " pointing to ";
-    PrintCharsAsStringTo(s, std::char_traits<Char>::length(s), os);
+    PrintCharsAsStringTo(s, GetLength(s), os);
   }
 }