perl: Fix utf8 mode not to be reseted by $unpacker->reset method

perl/Changes

@@ -1,3 +1,8 @@
+
+0.30
+
+    - fix utf8 mode not to be reseted by $unpacker->reset method
+
 0.29
 
     - add $unpacker->utf8 mode, decoding strings as UTF-8.

perl/t/15_utf8.t

@@ -5,23 +5,29 @@ use Data::MessagePack;
 use utf8;
 
 my $data = [42, undef, 'foo', "\x{99f1}\x{99dd}"];
-my $packed = Data::MessagePack->pack($data);
+my $packed = Data::MessagePack->pack($data) x 2;
 
 my $u = Data::MessagePack::Unpacker->new()->utf8();
-ok $u->get_utf8();
-$u->execute($packed);
-my $d = $u->data();
-$u->reset();
-is_deeply $d, $data, 'decoded';
+my $p = 0;
+for(1 .. 2) {
+    ok $u->get_utf8();
+    $p = $u->execute($packed, $p);
+    my $d = $u->data();
+    $u->reset();
+    is_deeply $d, $data, 'decoded';
+}
 
 is $u->utf8(0), $u, 'utf8(0)';
-ok !$u->get_utf8();
-$u->execute($packed);
-$d = $u->data();
-$u->reset();
-my $s = $data->[3];
-utf8::encode($s);
-is_deeply $d->[3], $s, 'not decoded';
+$p = 0;
+for(1 .. 2) {
+    ok !$u->get_utf8();
+    $p = $u->execute($packed, $p);
+    my $d = $u->data();
+    $u->reset();
+    my $s = $data->[3];
+    utf8::encode($s);
+    is_deeply $d->[3], $s, 'not decoded';
+}
 
 done_testing;
 

perl/xs-src/unpack.c

@@ -443,10 +443,12 @@ XS(xs_unpacker_reset) {
     }
 
     UNPACKER(ST(0), mp);
+    bool const utf8 = mp->user.utf8; // save
 
     SV* const data = template_data(mp);
     SvREFCNT_dec(data);
     _reset(ST(0));
+    mp->user.utf8 = utf8;
 
     XSRETURN(0);
 }