http://www.perlmonks.org?node_id=1079979


in reply to Re^2: DBD::Pg encodes Perlstring to UTF-8 bytes instead of WIN1252 regardless client encoding
in thread DBD::Pg encodes Perlstring to UTF-8 bytes instead of WIN1252 regardless client encoding

I've looked at DBD::mysql code and I cannot see anything that explains your "it's as if you actually passed".

Does it use SvPV(sv) without checking separate handling based on SvUTF8(sv)? It might do by using the default char* typemap (e.g. void xsfunc(char* s) { ... }).

As you can see, the following C function is equivalent to that code:

use strict; use warnings; use Test::More; use Encode qw( is_utf8 encode_utf8 ); use Inline C => <<'__EOC__'; void candidate(SV* sv) { dXSARGS; STRLEN len; char* buf = SvPV(sv, len); SP[0] = sv_2mortal(newSVpvn(buf, len)); XSRETURN(1); } __EOC__ sub baseline { is_utf8($_[0]) ? encode_utf8($_[0]) : $_[0] } sub _u { my ($s) = @_; utf8::upgrade($s); $s } sub _d { my ($s) = @_; utf8::downgrade($s); $s } sub printable { sprintf("%v04X", $_[0]) } my @tests = ( [ '00-7F', "a" ], [ '80-FF,UTF8=0', _d(chr(0xE9)) ], [ '80-FF,UTF8=1', _u(chr(0xE9)) ], [ '>FF', chr(0x2660) ], ); plan tests => 0+@tests; for (@tests) { my ($test_name, $input) = @$_; my $got = candidate($input); my $expected = baseline($input); #is($got, $expected, $test_name); is(printable($got), printable($expected), $test_name); }
1..4 ok 1 - 00-7F ok 2 - 80-FF,UTF8=0 ok 3 - 80-FF,UTF8=1 ok 4 - >FF

I'm really interested in this from the point of another DBD maintainer.

Using the same configuration for all tests, can you roundtrip all of the strings mentioned earlier (as verified by is or eq)?

my @tests = ( [ '00-7F', "a" ], [ '80-FF,UTF8=0', _d(chr(0xE9)) ], [ '80-FF,UTF8=1', _u(chr(0xE9)) ], [ '>FF', chr(0x2660) ], ); plan tests => 0+@tests; my $dbh = ... connect and setup as you wish ... my $sth = $dbh->prepare('SELECT ?'); for (@tests) { my ($test_name, $input) = @$_; $sth->execute($input) or die; my $row = $sth->fetch() or die; $sth->finish() or die if $row; my $got = $row->[0]; is(printable($got), printable($input), $test_name); }