[GraphHopper] No difference between shortest and fastest

[Peter]

>
> A) ghRequest.setWeighting("shortest") should fail fast:
>     it should throw an IllegalArgumentException as long as it's not
> supported

yes, indeed, please open an issue.
(It should already throw exceptions if unsupported algorithms are
specified.)

>
> B) I loaded a belgium osm.pbf with graphHopperLocation "belgium",
> then, in another run, I loaded a UK osm.pbf with the same
> graphHopperLocation (I forgot to change it).
> It loaded immediately, pretending to be successful and then failed
> when I queried for a UK location.
> That loading should fail fast too (or refresh the graphHopperLocation
> content to handle it correctly).

That is harder, because we do not store the source PBF in the graph
(should we?) and so we do not know if we have to throw an exception...

Regards,
Peter.