Deprecate futures::sleepUnsafe

Summary: Deprecate sleepUnsafe to avoid use growing and to clearly communicate the change.

Reviewed By: yfeldblum

Differential Revision: D14255404

fbshipit-source-id: cb2116910a15b9835fef9bf4273242457a5e96bd

folly/futures/helpers.h

@@ -46,7 +46,11 @@ namespace futures {
 /// needed. If your program never uses any timeouts or other time-based
 /// Futures you will pay no Timekeeper thread overhead.
 SemiFuture<Unit> sleep(Duration, Timekeeper* = nullptr);
-Future<Unit> sleepUnsafe(Duration, Timekeeper* = nullptr);
+[[deprecated(
+    "futures::sleep now returns a SemiFuture<Unit>. "
+    "sleepUnsafe is deprecated. "
+    "Please call futures::sleep and apply an executor with .via")]] Future<Unit>
+sleepUnsafe(Duration, Timekeeper* = nullptr);
 
 /**
  * Set func as the callback for each input Future and return a vector of

folly/futures/test/TimekeeperTest.cpp

@@ -79,11 +79,14 @@ TEST(Timekeeper, futureSleep) {
   EXPECT_GE(now() - t1, one_ms);
 }
 
+FOLLY_PUSH_WARNING
+FOLLY_GNU_DISABLE_WARNING("-Wdeprecated-declarations")
 TEST(Timekeeper, futureSleepUnsafe) {
   auto t1 = now();
   futures::sleepUnsafe(one_ms).get();
   EXPECT_GE(now() - t1, one_ms);
 }
+FOLLY_POP_WARNING
 
 TEST(Timekeeper, futureSleepHandlesNullTimekeeperSingleton) {
   Singleton<ThreadWheelTimekeeper>::make_mock([] { return nullptr; });