json_parse()/pgtypes: Fix accidental creation of read-only array/hash values

&PL_sv_* shouldn't be used when constructing arrays or hashes in this
context.

FU.xs

@@ -20,6 +20,12 @@
 #ifndef BOOL_INTERNALS_sv_isbool_true
 #define BOOL_INTERNALS_sv_isbool_true(x) SvTRUEx(x)
 #endif
+#ifndef newSV_true
+#define newSV_true() newSVsv(&PL_sv_yes)
+#endif
+#ifndef newSV_false
+#define newSV_false() newSVsv(&PL_sv_no)
+#endif
 
 /* Disable key/value struct packing in khashl, so we can safely take a pointer
  * to values inside the hash table. */

c/jsonparse.c

@@ -236,12 +236,12 @@ static SV *fujson_parse(pTHX_ fujson_parse_ctx *ctx) {
             if (ctx->end - ctx->buf < 4) return NULL;
             if (memcmp(ctx->buf, "true", 4) != 0) return NULL;
             ctx->buf += 4;
-            return &PL_sv_yes;
+            return newSV_true();
         case 'f':
             if (ctx->end - ctx->buf < 5) return NULL;
             if (memcmp(ctx->buf, "false", 5) != 0) return NULL;
             ctx->buf += 5;
-            return &PL_sv_no;
+            return newSV_false();
         case 'n':
             if (ctx->end - ctx->buf < 4) return NULL;
             if (memcmp(ctx->buf, "null", 4) != 0) return NULL;

c/pgst.c

@@ -463,7 +463,7 @@ static SV *fupg_st_kvv(pTHX_ fupg_st *st) {
         SAVETMPS;
         SV *key = sv_2mortal(fupg_st_getval(aTHX_ st, i, 0));
         if (hv_exists_ent(hv, key, 0)) fu_confess("Key '%s' is duplicated in $st->kvv() query results", SvPV_nolen(key));
-        hv_store_ent(hv, key, st->nfields == 1 ? &PL_sv_yes : fupg_st_getval(aTHX_ st, i, 1), 0);
+        hv_store_ent(hv, key, st->nfields == 1 ? newSV_true() : fupg_st_getval(aTHX_ st, i, 1), 0);
         FREETMPS;
     }
     return sv;

c/pgtypes.c

@@ -78,7 +78,7 @@ SENDFN(domain) { (void)out; SERR("domain type should not be handled by this func
 
 RECVFN(bool) {
     RLEN(1);
-    return *buf ? &PL_sv_yes : &PL_sv_no;
+    return *buf ? newSV_true() : newSV_false();
 }
 
 SENDFN(bool) {
@@ -89,7 +89,7 @@ SENDFN(bool) {
 RECVFN(void) {
     RLEN(0);
     (void)buf;
-    return &PL_sv_undef;
+    return newSV(0);
 }
 
 SENDFN(void) {
@@ -269,7 +269,7 @@ SENDFN(jsonpath) {
 #define ARRAY_MAXDIM 100
 
 static SV *fupg_recv_array_elem(pTHX_ const fupg_tio *elem, const char *header, U32 dim, U32 ndim, const char **buf, const char *end) {
-    SV *r = &PL_sv_undef;
+    SV *r;
     if (dim == ndim) {
         if (end - *buf < 4) fu_confess("Invalid array format");
         I32 len = fu_frombeI(32, *buf);
@@ -279,6 +279,8 @@ static SV *fupg_recv_array_elem(pTHX_ const fupg_tio *elem, const char *header,
         if (len >= 0) {
             r = elem->recv(aTHX_ elem, *buf, len);
             *buf += len;
+        } else {
+            r = newSV(0);
         }
 
     } else {
@@ -403,12 +405,14 @@ RECVFN(record) {
         if (oid != ctx->record.info->attrs[i].oid)
             RERR("expected field %d to be of type %u but got %u", i, ctx->record.info->attrs[i].oid, oid);
         I32 vlen = fu_frombeI(32, buf+4);
-        SV *r = &PL_sv_undef;
+        SV *r;
         buf += 8; len -= 8;
         if (vlen > len) RERR("input data too short");
         if (vlen >= 0) {
             r = ctx->record.tio[i].recv(aTHX_ ctx->record.tio+i, buf, vlen);
             buf += vlen; len -= vlen;
+        } else {
+            r = newSV(0);
         }
         hv_store(hv, ctx->record.info->attrs[i].name.n, -strlen(ctx->record.info->attrs[i].name.n), r, 0);
     }

t/json_parse.t

@@ -2,7 +2,7 @@ use v5.36;
 use Test::More;
 use FU::Util 'json_parse';
 no warnings 'experimental::builtin';
-use builtin 'is_bool', 'created_as_number';
+use builtin 'is_bool', 'created_as_number', 'true', 'false';
 use Config;
 
 my @error = (
@@ -236,4 +236,10 @@ ok !eval { json_parse '{"":{"":{"":{"":1}}}}', max_depth => 4; 1 };
     ok !eval { json_parse '"string"', max_size => 7 };
 }
 
+# Mutable hashes/arrays
+my $d = json_parse('[true,false,null,{"a":true,"b":false,"c":null}]');
+is_deeply $d, [true,false,undef,{a => true, b => false, c => undef}];
+$_ = 1 for @{$d}[0,1,2], values $d->[3]->%*;
+is_deeply $d, [1,1,1,{a => 1, b => 1, c => 1}];
+
 done_testing;

t/pgconnect.t

@@ -197,6 +197,7 @@ subtest '$st->kvv', sub {
     is_deeply $conn->q('SELECT 1 WHERE false')->kvv, {};
     is_deeply $conn->q('SELECT 1')->kvv, {1=>1};
     is_deeply $conn->q('SELECT 1, null UNION ALL SELECT 3, 2')->kvv, {1=>undef,3=>2};
+    $conn->q('SELECT 1')->kvv->{1} = 0;
 };
 
 subtest '$st->kva', sub {

t/pgtypes-dynamic.t

@@ -96,10 +96,15 @@ subtest 'custom types', sub {
         );
     _
 
-    is_deeply $txn->q(q{SELECT '{"(\"(2,{},bb)\",)","(\"(,,)\",bb)"}'::fupg_test_table[]})->val, [
+    $val = $txn->q(q{SELECT '{"(\"(2,{},bb)\",)","(\"(,,)\",bb)"}'::fupg_test_table[]})->val;
+    is_deeply $val, [
         { rec => { a => 2, aenum => [], domain => 'bb' }, dom => undef },
         { rec => { a => undef, aenum => undef, domain => undef }, dom => 'bb' },
     ];
+    $val->[0] = 0;
+    $val->[1]{rec}{a} = 0;
+    $val->[1]{rec} = 0;
+    $val->[1]{dom} = 0;
 
     is $txn->q('SELECT $1::fupg_test_table[]', [
         { rec => { a => 2, aenum => [], domain => 'bb' }, dom => undef },

t/pgtypes.t

@@ -21,10 +21,12 @@ sub v($type, $p_in, @args) {
     my $test = "$type $s_in" =~ s/\n/\\n/rg;
     utf8::encode($test);
     {
-        my $res = $conn->q("SELECT \$1::$type", $s_in)->text_params->val;
+        my $array = $conn->q("SELECT \$1::$type", $s_in)->text_params->flat;
+        my $res = $array->[0];
         ok is_bool($res), "$test is bool" if $type eq 'bool';
         ok created_as_number($res), "$test is number" if $type =~ /^(int|float)\d/;
         is_deeply $res, $p_out, "$test text->bin";
+        $array->[0] = 0; # Must be writable
     }
     {
         my $res = $conn->q("SELECT \$1::$type", $p_in)->text_results->val;
@@ -41,7 +43,11 @@ sub f($type, $p_in) {
     ok !eval { $conn->q("SELECT \$1::$type", $p_in)->val; 1 }, "$test fail";
 }
 
-ok !defined $conn->q('SELECT pg_sleep(0)')->val; # void
+{ # void
+    my $array = $conn->q('SELECT pg_sleep(0)')->flat;
+    ok !defined $array->[0];
+    $array->[0] = 0;
+}
 
 v bool => true,  undef, 1, 't';
 v bool => false, undef, 0, 'f';
@@ -166,4 +172,10 @@ is $conn->q('SELECT ($1::int2[])[2]', [1,2,3,4])->val, 2;
 is $conn->q('SELECT ($1::int2vector)[1]', [1,2,3,4])->val, 2;
 is $conn->q('SELECT ($1::oidvector)[1]', [1,2,3,4])->val, 2;
 
+{
+    my $v = $conn->q("SELECT '{t,f,NULL}'::bool[]")->val;
+    is_deeply $v, [true, false, undef];
+    $_ = 0 for @$v;
+}
+
 done_testing;