[Boost-bugs] [Boost C++ Libraries] #13563: Error deserializing empty forward_list

Subject: [Boost-bugs] [Boost C++ Libraries] #13563: Error deserializing empty forward_list
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2018-05-11 12:03:11

#13563: Error deserializing empty forward_list
----------------------------------------+---------------------------
 Reporter:  Maximiliano Pin <mxcpin@…>  |      Owner:  Robert Ramey
     Type:  Patches                     |     Status:  new
Milestone:  To Be Determined            |  Component:  serialization
  Version:  Boost 1.67.0                |   Severity:  Showstopper
 Keywords:                              |
----------------------------------------+---------------------------
 Deserializing an empty forward_list is broken if the elements aren't
 default constructible (with old compilers it's enough that elements have a
 non-trivial default constructor).

 A patch is attached. The problem is that the first element is always
 loaded first, even if the list is empty. The result may be a crash or any
 undefined behavior, since deserialization goes out of sync.

 Test case:
 {{{
 #include <boost/serialization/forward_list.hpp>
 #include <boost/archive/binary_iarchive.hpp>
 #include <boost/archive/binary_oarchive.hpp>

 #include <forward_list>
 #include <iostream>
 #include <sstream>

 struct Foo
 {
   int x;
   Foo(int a) : x(a) {};

   template<class Archive>
   void serialize(Archive& ar, const unsigned int) { ar & x; }

 private:
   friend class boost::serialization::access;
   Foo() = default;
 };

 int main()
 {
   std::forward_list<Foo> flist;

   std::ostringstream oss;
   boost::archive::binary_oarchive oa{oss};
   oa << flist;

   std::istringstream iss{oss.str()};
   boost::archive::binary_iarchive ia{iss};
   ia >> flist;
 }
 }}}

 Results in:
 {{{
 terminate called after throwing an instance of
 'boost::archive::archive_exception'
   what():  input stream error
 Aborted (core dumped)
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac10/ticket/13563>
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