From be2ff22a825855813c8e79c287e037d1dce66c7f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Tue, 13 Nov 2018 22:19:30 +0100
Subject: [PATCH] Fix GitHub #90 ("UBSAN failures detected in preflight CI PR")

---
 doc/container.qbk                                 |  2 ++
 .../container/detail/multiallocation_chain.hpp    | 15 ++++++++++-----
 include/boost/container/pmr/resource_adaptor.hpp  |  2 +-
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/doc/container.qbk b/doc/container.qbk
index 637bdeb..2061f27 100644
--- a/doc/container.qbk
+++ b/doc/container.qbk
@@ -1261,6 +1261,8 @@ use [*Boost.Container]? There are several reasons for that:
    * [@https://github.com/boostorg/container/pull/84   GitHub #84: ['"Allow vector to be assigned to itself"]].
    * [@https://github.com/boostorg/container/pull/85   GitHub #85: ['"container: misc-typos"]].
    * [@https://github.com/boostorg/container/pull/86   GitHub #86: ['"Add missing warning re-enabling include"]].
+   * [@https://github.com/boostorg/container/issues/90 GitHub #90: ['"UBSAN failures detected in preflight CI PR "]].
+
 
 [endsect]
 
diff --git a/include/boost/container/detail/multiallocation_chain.hpp b/include/boost/container/detail/multiallocation_chain.hpp
index bc3b285..c7d94f4 100644
--- a/include/boost/container/detail/multiallocation_chain.hpp
+++ b/include/boost/container/detail/multiallocation_chain.hpp
@@ -171,11 +171,16 @@ class basic_multiallocation_chain
 
    std::pair<void_pointer, void_pointer> extract_data()
    {
-      std::pair<void_pointer, void_pointer> ret
-         (slist_impl_.begin().operator->()
-         ,slist_impl_.last().operator->());
-      slist_impl_.clear();
-      return ret;
+      if(BOOST_LIKELY(!slist_impl_.empty())){
+         std::pair<void_pointer, void_pointer> ret
+            (slist_impl_.begin().operator->()
+            ,slist_impl_.last().operator->());
+         slist_impl_.clear();
+         return ret;
+      }
+      else {
+         return std::pair<void_pointer, void_pointer>();
+      }
    }
 };
 
diff --git a/include/boost/container/pmr/resource_adaptor.hpp b/include/boost/container/pmr/resource_adaptor.hpp
index f5ce5c8..3340626 100644
--- a/include/boost/container/pmr/resource_adaptor.hpp
+++ b/include/boost/container/pmr/resource_adaptor.hpp
@@ -172,7 +172,7 @@ class resource_adaptor
    {}
 
    explicit resource_adaptor(BOOST_RV_REF(Allocator) a2)
-      : base_t(BOOST_MOVE_BASE(base_t, a2))
+      : base_t(::boost::move(a2))
    {}
 
    resource_adaptor& operator=(BOOST_COPY_ASSIGN_REF(resource_adaptor) other)