Potential issue in casting numbers about msgpack-perl HOT 2 OPEN

Perl treats -1.0 as double(NV means double as below), so it is packaged as float64 whose packed size is 9 byte.

% perl -MDevel::Peek -e 'my $i = "-1.000000" + 0; Dump $i'  
SV = NV(0x7fb52a02d718) at 0x7fb52a02d730
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  NV = -1

from msgpack-perl.

What is interesting is that this does not seem to be the case if you pass "-1.000" + 0 to pack() (length($packed) == 1). Returning "-1.000" + 0 from a sub, and passing that to pack() indeed results in 9 bytes.

It could be useful for prefer_integer() to also check whether a double can be stored as an int, possibly with an optional flag.

from msgpack-perl.