The need for this is that:
- On OS X if libraries are stored in custom locations (not /usr/lib or /usr/local)
and they do not embed an rpath (which is common to not have) then the developer
needs to set DYLD_LIBRARY_PATH to ensure that osrm tools can find dependent libraries
at runtime (this is normal and common).
- But as of OS X > 10.11 DYLD_LIBRARY_PATH no longer is inherited. While it works in
the main shell when running a command like `osrm-extract` you will find that when
`osrm-extract` is run by cucumber (ruby child process) then DYLD_LIBRARY_PATH
is blocked and the command cannot start.
- So, this introduces the ability to pass in a variable that the cucumber tests will
understand and can manually forward along to ensure that DYLD_LIBRARY_PATH is respected
where it counts.
The intended usage of this is therefore:
# set the environment variable
export OSRM_SHARED_LIBRARY_PATH=${DYLD_LIBRARY_PATH}
# then run cucumber tests
cucumber -p verify
- Otherwise, currently, if osrm-extract crashes at startup then
the tests continue on and will crash many many times.
- This also tests that --help returns an exit code of zero and will
catch if this behavior ever changes or is inconsistent between
the command line programs
Phew, a lot of classes were affected by this. The rationale for the
changes are as follows:
- When a type X declares any constructor, the default constructor is
not declared, so there is no need for X() = delete there. In fact,
there is brutal difference between those two: deleted members
participate in overload resolution, but not-declared members do not!
- When a type X wants to be non-copyable (e.g. to be only movable, like
threads, unique_ptrs, and so on), you can either do it by inheriting
from boost::noncopyable (the old way), or better declare both (!) the
copy constructor _and_ the copy assignment operator as deleted:
X(X const&) = delete;
X& operator=(X const&) = delete;
We had tons of types with deleted copy constructors that were lacking
a corresponding deleted copy assignment operator, making them still
copyable and you wouldn't even notice (read: scary)!
References:
- http://accu.org/content/conf2014/Howard_Hinnant_Accu_2014.pdf
- http://www.boost.org/doc/libs/master/libs/core/doc/html/core/noncopyable.html
Note: I know, I'm quoting Hinnant's extraordinary slides a lot, but
getting the sematic right here is so incredibly important.
