[Boost-bugs] [Boost C++ Libraries] #10084: void_upcast should throw an unregistered_cast exception when it can't find a way to upcast

Subject: [Boost-bugs] [Boost C++ Libraries] #10084: void_upcast should throw an unregistered_cast exception when it can't find a way to upcast
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-05-31 14:11:42

#10084: void_upcast should throw an unregistered_cast exception when it can't find
a way to upcast
---------------------------------------------+---------------------------
 Reporter:  Steve Hickman <steve.hickman@…>  |      Owner:  ramey
     Type:  Bugs                             |     Status:  new
Milestone:  To Be Determined                 |  Component:  serialization
  Version:  Boost 1.55.0                     |   Severity:  Problem
 Keywords:                                   |
---------------------------------------------+---------------------------
 It is possible for the void_caster_register to not include information on
 how to upcast between types. In version 1.55,
 void_upcast(lines 314-334) in void_cast.cpp searches the
 void_caster_register for this information and, if it finds none, returns
 NULL. If this happens when doing deserialization, it means that all of the
 deserialized data is thrown away (event though it may have been
 successfully completed) and the user gets a null pointer back instead. At
 a minimum, this results in mysterious behavior when deserializing derived
 classes through a base class pointer. At worst, this may result in a
 memory leak (haven't investigated this).  It seems to me that rather than
 surprising the user like this, failures to find appropriate cast info in
 the void_caster_register should cause an unregistered_cast exception (or
 something similar) so the user will at least know where the problem is.
 This can happen even though void_upcast the appropriate type information
 for both the base and derived class.

 This problem occurs when the void_caster_register is empty, which has
 happened when both Boost.Serialize and the library of classes to be
 serialized are created as DLLs on Windows 7 when building using VS2012.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10084>
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