From: Yedidya Feldblum <yfeldblum@fb.com>
Date: Sat, 9 Dec 2017 17:47:06 +0000 (-0800)
Subject: Fix UBSAN failure in RangeTest.cpp with libstdc++-v4.9
X-Git-Tag: v2017.12.11.00~5
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=2d3c33462242cada87a857143101cd99cd94b8f8;p=folly.git

Fix UBSAN failure in RangeTest.cpp with libstdc++-v4.9

Summary:
[Folly] Fix UBSAN failure in `RangeTest.cpp` with `libstdc++-v4.9`.

The implementation of `std::array` in `libstdc++-v4.9` has undefined behavior in the case of the zero-length array - dereferencing (but immediately taking the address again) of `nullptr`. This is fixed in `libstdc++-v5`.

Reviewed By: ot

Differential Revision: D6528614

fbshipit-source-id: 26be6bdc28d9e6dc6e6293a4d4ecffd769c01413
---

diff --git a/folly/test/RangeTest.cpp b/folly/test/RangeTest.cpp
index dbe8d88f..b1298cac 100644
--- a/folly/test/RangeTest.cpp
+++ b/folly/test/RangeTest.cpp
@@ -1201,7 +1201,7 @@ TEST(CRangeFunc, StdArrayZero) {
   auto const numArrayRange = crange(numArray);
   EXPECT_TRUE(
       (std::is_same<int const*, decltype(numArrayRange)::iterator>::value));
-  EXPECT_THAT(numArrayRange, testing::ElementsAreArray(numArray));
+  EXPECT_THAT(numArrayRange, testing::IsEmpty());
 }
 
 TEST(CRangeFunc, Collection) {