[] Future<T>::then Future<T>::then(not-try-task) -> Future<T>::thenValue(task). - 5/11

Summary:
Part of the larger project to modify Future<T>::then to be r-value qualified and use Future<T>::thenTry or Future<T>::thenValue.

The goal is to disambiguate folly::Future and to improve type and lifetime safety of Future and its methods.

Codemod:
  future<T>.then(callable with operator()(not-a-try)) to future<T>.thenValue(callable with operator()(not-a-try)).
  future<T>.then(callable with operator()()) to future<T>.thenValue(callable with operator()(auto&&)).
  future<T>.then(callable with operator()(auto)) to future<T>.thenValue(callable with operator()(auto)).

Reviewed By: Orvid

Differential Revision: D9696740

fbshipit-source-id: 9fc199931870bbecfece22ebfaebbda41d4b1d29

Author: LeeHowes

rsocket/test/RSocketClientServerTest.cpp

@@ -58,10 +58,11 @@ TEST(RSocketClientServer, ConnectManyAsync) {
     auto clientFuture =
         makeClientAsync(
             workers[workerId].getEventBase(), *server->listeningPort())
-            .then([&executed](std::shared_ptr<rsocket::RSocketClient> client) {
-              ++executed;
-              return client;
-            })
+            .thenValue(
+                [&executed](std::shared_ptr<rsocket::RSocketClient> client) {
+                  ++executed;
+                  return client;
+                })
             .onError([&](folly::exception_wrapper ex) {
               LOG(ERROR) << "error: " << ex.what();
               ++executed;

rsocket/test/RSocketClientTest.cpp

@@ -36,7 +36,7 @@ TEST(RSocketClient, ConnectFails) {
           *worker.getEventBase(), std::move(address)));
 
   std::move(client)
-      .then([&](auto&&) { FAIL() << "the test needs to fail"; })
+      .thenValue([&](auto&&) { FAIL() << "the test needs to fail"; })
       .onError([&](const std::exception&) {
         LOG(INFO) << "connection failed as expected";
       })

rsocket/test/WarmResumptionTest.cpp

@@ -44,7 +44,7 @@ TEST(WarmResumptionTest, SuccessfulResumption) {
   }
   auto result =
       client->disconnect(std::runtime_error("Test triggered disconnect"))
-          .then([&] { return client->resume(); });
+          .thenValue([&](auto&&) { return client->resume(); });
   EXPECT_NO_THROW(std::move(result).get());
   ts->request(3);
   ts->awaitTerminalEvent();
@@ -71,8 +71,9 @@ TEST(WarmResumptionTest, FailedResumption1) {
   }
 
   client->disconnect(std::runtime_error("Test triggered disconnect"))
-      .then([&] { return client->resume(); })
-      .then([] { FAIL() << "Resumption succeeded when it should not"; })
+      .thenValue([&](auto&&) { return client->resume(); })
+      .thenValue(
+          [](auto&&) { FAIL() << "Resumption succeeded when it should not"; })
       .onError([listeningPort, &worker](folly::exception_wrapper) {
         folly::ScopedEventBaseThread worker2;
         auto newClient =
@@ -118,8 +119,9 @@ TEST(WarmResumptionTest, FailedResumption2) {
   std::shared_ptr<RSocketClient> newClient;
 
   client->disconnect(std::runtime_error("Test triggered disconnect"))
-      .then([&] { return client->resume(); })
-      .then([] { FAIL() << "Resumption succeeded when it should not"; })
+      .thenValue([&](auto&&) { return client->resume(); })
+      .thenValue(
+          [](auto&&) { FAIL() << "Resumption succeeded when it should not"; })
       .onError([listeningPort, newTs, &newClient, &worker2](
                    folly::exception_wrapper) {
         newClient =
@@ -162,7 +164,7 @@ TEST(WarmResumptionTest, DifferentEvb) {
   }
   auto result =
       client->disconnect(std::runtime_error("Test triggered disconnect"))
-          .then([&] { return client->resume(); });
+          .thenValue([&](auto&&) { return client->resume(); });
   EXPECT_NO_THROW(std::move(result).get());
   ts->request(3);
   ts->awaitTerminalEvent();

rsocket/test/transport/TcpDuplexConnectionTest.cpp

@@ -60,8 +60,8 @@ makeSingleClientServer(
   auto client = std::make_unique<TcpConnectionFactory>(
       *clientEvb, SocketAddress("localhost", port, true));
   client->connect(ProtocolVersion::Latest, ResumeStatus::NEW_SESSION)
-      .then([&clientConnection](
-                ConnectionFactory::ConnectedDuplexConnection connection) {
+      .thenValue([&clientConnection](
+                     ConnectionFactory::ConnectedDuplexConnection connection) {
         clientConnection = std::move(connection.connection);
       })
       .wait();