Fix for lifetime bug in retrying.

Summary: Late change in D9175807 removed necessary temporaries. This caused a lifetime management problem for GCC.

Reviewed By: Orvid

Differential Revision: D9227937

fbshipit-source-id: d5fea8a98855c6302189a7dee8cd5862d13a63a3

folly/futures/Retrying.h

@@ -83,31 +83,31 @@ template <class Policy, class FF, class Prom>
 void retryingImpl(size_t k, Policy&& p, FF&& ff, Prom prom) {
   using F = invoke_result_t<FF, size_t>;
   using T = typename F::value_type;
-  makeFutureWith([&] { return ff(k++); })
-      .then([k,
-             prom = std::move(prom),
-             pm = std::forward<Policy>(p),
-             ffm = std::forward<FF>(ff)](Try<T>&& t) mutable {
-        if (t.hasValue()) {
-          prom.setValue(std::move(t).value());
-          return;
-        }
-        auto& x = t.exception();
-        makeFutureWith([&] { return pm(k, x); })
-            .then([k,
-                   prom = std::move(prom),
-                   xm = std::move(x),
-                   pm = std::move(pm),
-                   ffm = std::move(ffm)](Try<bool> shouldRetry) mutable {
-              if (shouldRetry.hasValue() && shouldRetry.value()) {
-                retryingImpl(k, std::move(pm), std::move(ffm), std::move(prom));
-              } else if (shouldRetry.hasValue()) {
-                prom.setException(std::move(xm));
-              } else {
-                prom.setException(std::move(shouldRetry.exception()));
-              }
-            });
-      });
+  auto f = makeFutureWith([&] { return ff(k++); });
+  f.then([k,
+          prom = std::move(prom),
+          pm = std::forward<Policy>(p),
+          ffm = std::forward<FF>(ff)](Try<T>&& t) mutable {
+    if (t.hasValue()) {
+      prom.setValue(std::move(t).value());
+      return;
+    }
+    auto& x = t.exception();
+    auto q = makeFutureWith([&] { return pm(k, x); });
+    q.then([k,
+            prom = std::move(prom),
+            xm = std::move(x),
+            pm = std::move(pm),
+            ffm = std::move(ffm)](Try<bool> shouldRetry) mutable {
+      if (shouldRetry.hasValue() && shouldRetry.value()) {
+        retryingImpl(k, std::move(pm), std::move(ffm), std::move(prom));
+      } else if (shouldRetry.hasValue()) {
+        prom.setException(std::move(xm));
+      } else {
+        prom.setException(std::move(shouldRetry.exception()));
+      }
+    });
+  });
 }
 
 template <class Policy, class FF>