Fix/boost issue #713 again

[Alevs2R]

Fixes issue #634
Fixes order of #include <boost/serialization/version.hpp> headers

My compilation on Ubuntu failed with the same error as in issue #634
Changing order of includes fixed my compilation.

<boost/serialization/version.hpp> should be included before <boost/serialization/list.hpp> and before <boost/shared_ptr.hpp>, not after.

Also it was needed to add includes to FastList.h to avoid the same compilation errors.

boost version: 1.74.0
gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)

Probably this issue will not appear in boost version 1.75, but I tested only with 1.74

[ProfFan]

LGTM, thanks!

[ProfFan]

@varunagrawal What do you think?

[varunagrawal]

Any reason you have added the <boost/serialization/optional.hpp> headers for FastList.h and SubgraphBuilder.h?

[Alevs2R]

To be precise, I started again with the latest develop version and iteratively added changes to get rid of the errors:

1. First error was this

In file included from /apollo/gtsam/gtsam/base/FastList.h:25:0:
/opt/apollo/sysroot/include/boost/serialization/list.hpp: In function 'void boost::serialization::load(Archive&, std::__cxx11::list<U, Allocator>&, unsigned int)':
/opt/apollo/sysroot/include/boost/serialization/list.hpp:53:33: error: 'library_version_type' in namespace 'boost::serialization' does not name a type
     const boost::serialization::library_version_type library_version(

I added #include <boost/serialization/version.hpp> into FastList.h, but still get the same error.
Then I added #include <boost/serialization/optional.hpp> and error disappeared.

2. Second error looked like this

In file included from /apollo/gtsam/gtsam/linear/LossFunctions.h:28:0,
                 from /apollo/gtsam/gtsam/linear/LossFunctions.cpp:19:
/opt/apollo/sysroot/include/boost/serialization/optional.hpp:98:8: error: 'version' is not a class template
 struct version<boost::optional<T> > {
        ^~~~~~~
In file included from /opt/apollo/sysroot/include/boost/serialization/shared_ptr.hpp:32:0,
                 from /apollo/gtsam/gtsam/linear/LossFunctions.h:29,
                 from /apollo/gtsam/gtsam/linear/LossFunctions.cpp:19:
/opt/apollo/sysroot/include/boost/serialization/version.hpp:36:8: error: redefinition of 'struct boost::serialization::version<T>'
 struct version
        ^~~~~~~

I simply moved include of boost/serialization/version.hpp to line 28 from line 31 in LossFunctions.h and compilation succeeded.
3. I removed the line #include <boost/serialization/version.hpp> from gtsam/linear/SubgraphBuilder.h at all and compilation succeeded anyway. This line was added in MR #713 and it means that we don't really need this include. Why it was added here?

[Alevs2R]

Any reason you have added the <boost/serialization/optional.hpp> headers for FastList.h and SubgraphBuilder.h?

As my inspection showed, it is needed for FastList.h, but is not needed for SubgraphBuilder.h, thank you for the comment. It would be great if someone with boost version 1.74.0 checked it also.

[varunagrawal]

@Alevs2R please add back the header to SubgraphBuilder.h since I believe that is required to work on Boost 1.74. Once you do that, I can approve.

Thanks a lot for the great work and explanation!!

[Alevs2R]

@varunagrawal done!

[varunagrawal]

LGTM! Thanks a lot @Alevs2R

[varunagrawal]

Please merge once the CI passes. :)