From 0e7c824d239f6668be1afb2ffd334f89ce294c80 Mon Sep 17 00:00:00 2001
From: Eric Niebler <eniebler@fb.com>
Date: Fri, 13 Jan 2017 12:16:51 -0800
Subject: [PATCH] capture exception information when creating exception_wrapper

Summary:
prefer creating an exception_wrapper with a reference to the active exception

Depends on D4410421

Reviewed By: spacedentist

Differential Revision: D4410455

fbshipit-source-id: d6b6aeb5fa72782e31d754a0b853514af5fdb8cd
---
 folly/futures/detail/Core.h              | 8 +++++++-
 folly/futures/test/PromiseTest.cpp       | 2 ++
 folly/futures/test/SharedPromiseTest.cpp | 4 ++--
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/folly/futures/detail/Core.h b/folly/futures/detail/Core.h
index 41fcdab2..be8e4b99 100644
--- a/folly/futures/detail/Core.h
+++ b/folly/futures/detail/Core.h
@@ -356,6 +356,7 @@ class Core final {
     }
 
     if (x) {
+      exception_wrapper ew;
       try {
         if (LIKELY(x->getNumPriorities() == 1)) {
           x->add([core_ref = CountedReference(this)]() mutable {
@@ -374,10 +375,15 @@ class Core final {
             core->callback_(std::move(*core->result_));
           }, priority);
         }
+      } catch (const std::exception& e) {
+        ew = exception_wrapper(std::current_exception(), e);
       } catch (...) {
+        ew = exception_wrapper(std::current_exception());
+      }
+      if (ew) {
         CountedReference core_ref(this);
         RequestContextScopeGuard rctx(context_);
-        result_ = Try<T>(exception_wrapper(std::current_exception()));
+        result_ = Try<T>(std::move(ew));
         SCOPE_EXIT { callback_ = {}; };
         callback_(std::move(*result_));
       }
diff --git a/folly/futures/test/PromiseTest.cpp b/folly/futures/test/PromiseTest.cpp
index 559391a2..ff9cef9c 100644
--- a/folly/futures/test/PromiseTest.cpp
+++ b/folly/futures/test/PromiseTest.cpp
@@ -92,6 +92,8 @@ TEST(Promise, setException) {
     auto f = p.getFuture();
     try {
       throw eggs;
+    } catch (const std::exception& e) {
+      p.setException(exception_wrapper(std::current_exception(), e));
     } catch (...) {
       p.setException(exception_wrapper(std::current_exception()));
     }
diff --git a/folly/futures/test/SharedPromiseTest.cpp b/folly/futures/test/SharedPromiseTest.cpp
index 7a4ea320..a449bf60 100644
--- a/folly/futures/test/SharedPromiseTest.cpp
+++ b/folly/futures/test/SharedPromiseTest.cpp
@@ -146,8 +146,8 @@ TEST(SharedPromise, splitFutureFailure) {
   EXPECT_FALSE(f1.isReady());
   try {
     throw std::runtime_error("Oops");
-  } catch (...) {
-    p.setException(exception_wrapper(std::current_exception()));
+  } catch (const std::exception& e) {
+    p.setException(exception_wrapper(std::current_exception(), e));
   }
   EXPECT_TRUE(f1.isReady());
   EXPECT_TRUE(f1.hasException());
-- 
2.34.1