Re: [Boost-bugs] [Boost C++ Libraries] #12321: save for boost::optional doesn't call save_construct_data but load calls load_construct_data

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #12321: save for boost::optional doesn't call save_construct_data but load calls load_construct_data
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-11-06 21:38:02

#12321: save for boost::optional doesn't call save_construct_data but load calls
load_construct_data
------------------------------------------------+--------------------------
  Reporter:  Oleg Burchakov <burchakov.oleg@…>  |      Owner:  ramey
      Type:  Bugs                               |     Status:  closed
 Milestone:  To Be Determined                   |  Component:
   Version:  Boost 1.61.0                       |  serialization
Resolution:  fixed                              |   Severity:  Problem
                                                |   Keywords:
------------------------------------------------+--------------------------

Comment (by ramey):

 I had fixed your example and checked it in.  But upon doing more testing I
 concluded that my "fix" would just break something else.  Spending a lot
 more time  on this convinced me that the root cause of the problem is the
 serialization of a type which out a default constructor.  The library as
 currently constituted really can't do that - this is not due to the usage
 of "optional" it's a general limitation.  Maybe if I made the library
 again I might address this limitation.  Or maybe I tried originally but
 just accepted the limitation (without documenting it).  So I'm going to
 make a few changes.

 a) fix it (again!) so that the test works.  This will make your case fail

 b) update the documentation to clarify this point.  There is a workaround.
 If a class has no default constructor it CAN be serialized through a
 pointer while overloading save/load construct data.

 c) use the boost type trait "has_default_constructor" to trap violations
 of tis rule and point to an explanation.

 Sorry you'll have to work around this.

 Robert Ramey

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12321#comment:4>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.