There's a logical error here https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/cast.cc#L239
The cast constexpr in_type kMax = static_cast<in_type>(std::numeric_limits<out_type>::max()); is overflowing int32_t This code path was only written for the unsigned-to-signed case. The functors need to be reworked to accommodate the signed-to-unsigned cast On Wed, Nov 14, 2018 at 8:36 AM Francois Saint-Jacques <fsaintjacq...@networkdump.com> wrote: > > Seems like the type combination you're using (int32 -> uint32) and (int32 > -> uint64) don't match the following pattern-matching > > https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/cast.cc#L191-L192 > > which avoid using "safe" cast and revert to the following cast > implementation (with no explicit check): > > https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/cast.cc#L316-L318 > > My take on this is that downcasting concept should only apply to same sign > integers. I'd propose the following refactor: > > 1. Rename `allow_int_overflow` to `allow_int_truncate`. Since truncation is > still applicable even if there's no downcasting. > 2. Refactor code such that the pattern matching is done on possible > truncation and not downcasting. The fast casting is only applied to > same-sign and size(O) >= size(I). The (possible according to > allow_int_truncate) slow and bound checking is done when signed-ness is not > matching or there's downcasting. > > Can you open a JIRA ticket? > > François > > On Wed, Nov 14, 2018 at 6:10 AM Romain Francois <rom...@purrple.cat> wrote: > > > I'm implementing Array$cast() in the R package, i.e. > > https://issues.apache.org/jira/browse/ARROW-3741?filter=12344983 > > > > I'm seeing some weird results when casting from int32 to uint32 and uint64 > > (I'm expecting errors here as it's supposed to be safe > > > > https://github.com/apache/arrow/pull/2959#issuecomment-438606974 > > > > a <- array(-(1:3)) > > a$cast(uint16()) > > #> Error in Array__cast(self, target_type, options): Invalid: Integer > > value out of bounds > > a$cast(uint16()) > > #> Error in Array__cast(self, target_type, options): Invalid: Integer > > value out of bounds > > a$cast(uint32()) > > #> arrow::Array > > #> [ > > #> 4294967295, > > #> 4294967294, > > #> 4294967293 > > #> ] > > a$cast(uint32())$type() > > #> arrow::UInt32 > > #> uint32 > > > > a$cast(uint64()) > > #> arrow::Array > > #> [ > > #> -1, > > #> -2, > > #> -3 > > #> ] > > a$cast(uint64())$type() > > #> arrow::UInt64 > > #> uint64 > > > > I don't think this is an R issue. > > > > Can someone using other front ends to the C++ library check if they get > > the same problem ? > > > > > > > > > > -- > Sent from my jetpack.
