From c144d78f8295da3dbae3ad2d5fe66a9a42f8ce74 Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Tue, 26 Apr 2022 14:39:03 -0700
Subject: [PATCH] Support move-only and &&-qualified actions in WithArgs.

PiperOrigin-RevId: 444671005
Change-Id: I7df5f038caf17afb60d4fb35434ff0b656d4c954
---
 googlemock/include/gmock/gmock-actions.h | 57 +++++++++++++++++++++---
 googlemock/test/gmock-actions_test.cc    | 25 ++++++++++-
 2 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/googlemock/include/gmock/gmock-actions.h b/googlemock/include/gmock/gmock-actions.h
index ecc72d5348..5836f17938 100644
--- a/googlemock/include/gmock/gmock-actions.h
+++ b/googlemock/include/gmock/gmock-actions.h
@@ -1279,17 +1279,60 @@ class IgnoreResultAction {
 
 template <typename InnerAction, size_t... I>
 struct WithArgsAction {
-  InnerAction action;
+  InnerAction inner_action;
 
-  // The inner action could be anything convertible to Action<X>.
-  // We use the conversion operator to detect the signature of the inner Action.
+  // The signature of the function as seen by the inner action, given an out
+  // action with the given result and argument types.
   template <typename R, typename... Args>
+  using InnerSignature =
+      R(typename std::tuple_element<I, std::tuple<Args...>>::type...);
+
+  // Rather than a call operator, we must define conversion operators to
+  // particular action types. This is necessary for embedded actions like
+  // DoDefault(), which rely on an action conversion operators rather than
+  // providing a call operator because even with a particular set of arguments
+  // they don't have a fixed return type.
+
+  template <typename R, typename... Args,
+            typename std::enable_if<
+                std::is_convertible<
+                    InnerAction,
+                    // Unfortunately we can't use the InnerSignature alias here;
+                    // MSVC complains about the I parameter pack not being
+                    // expanded (error C3520) despite it being expanded in the
+                    // type alias.
+                    OnceAction<R(typename std::tuple_element<
+                                 I, std::tuple<Args...>>::type...)>>::value,
+                int>::type = 0>
+  operator OnceAction<R(Args...)>() && {  // NOLINT
+    struct OA {
+      OnceAction<InnerSignature<R, Args...>> inner_action;
+
+      R operator()(Args&&... args) && {
+        return std::move(inner_action)
+            .Call(std::get<I>(
+                std::forward_as_tuple(std::forward<Args>(args)...))...);
+      }
+    };
+
+    return OA{std::move(inner_action)};
+  }
+
+  template <typename R, typename... Args,
+            typename std::enable_if<
+                std::is_convertible<
+                    const InnerAction&,
+                    // Unfortunately we can't use the InnerSignature alias here;
+                    // MSVC complains about the I parameter pack not being
+                    // expanded (error C3520) despite it being expanded in the
+                    // type alias.
+                    Action<R(typename std::tuple_element<
+                             I, std::tuple<Args...>>::type...)>>::value,
+                int>::type = 0>
   operator Action<R(Args...)>() const {  // NOLINT
-    using TupleType = std::tuple<Args...>;
-    Action<R(typename std::tuple_element<I, TupleType>::type...)> converted(
-        action);
+    Action<InnerSignature<R, Args...>> converted(inner_action);
 
-    return [converted](Args... args) -> R {
+    return [converted](Args&&... args) -> R {
       return converted.Perform(std::forward_as_tuple(
           std::get<I>(std::forward_as_tuple(std::forward<Args>(args)...))...));
     };
diff --git a/googlemock/test/gmock-actions_test.cc b/googlemock/test/gmock-actions_test.cc
index e41845e70f..a33358a76b 100644
--- a/googlemock/test/gmock-actions_test.cc
+++ b/googlemock/test/gmock-actions_test.cc
@@ -1444,8 +1444,29 @@ TEST(WithArgsTest, ReturnReference) {
 
 TEST(WithArgsTest, InnerActionWithConversion) {
   Action<Derived*()> inner = [] { return nullptr; };
-  Action<Base*(double)> a = testing::WithoutArgs(inner);
-  EXPECT_EQ(nullptr, a.Perform(std::make_tuple(1.1)));
+
+  MockFunction<Base*(double)> mock;
+  EXPECT_CALL(mock, Call)
+      .WillOnce(WithoutArgs(inner))
+      .WillRepeatedly(WithoutArgs(inner));
+
+  EXPECT_EQ(nullptr, mock.AsStdFunction()(1.1));
+  EXPECT_EQ(nullptr, mock.AsStdFunction()(1.1));
+}
+
+// It should be possible to use an &&-qualified inner action as long as the
+// whole shebang is used as an rvalue with WillOnce.
+TEST(WithArgsTest, RefQualifiedInnerAction) {
+  struct SomeAction {
+    int operator()(const int arg) && {
+      EXPECT_EQ(17, arg);
+      return 19;
+    }
+  };
+
+  MockFunction<int(int, int)> mock;
+  EXPECT_CALL(mock, Call).WillOnce(WithArg<1>(SomeAction{}));
+  EXPECT_EQ(19, mock.AsStdFunction()(0, 17));
 }
 
 #if !GTEST_OS_WINDOWS_MOBILE