Fix platform and Perl-version dependencies in new jsonb_plperl code.

Testing SvTYPE() directly is more fraught with problems than one might
think, because depending on context Perl might be storing a scalar value
in one of several forms, eg both numeric and string values.  This resulted
in Perl-version-dependent buildfarm test failures.  Instead use the SvTYPE
test only to distinguish non-scalar cases (AV, HV, NULL).  Disambiguate
scalars by testing SvIOK, SvNOK, then SvPOK.  This creates a preference
order for how we will resolve cases where the value is available in more
than one form, which seems fine to me.

Furthermore, because we're now dealing directly with a "double" value
in the SvNOK case, we can get rid of an inadequate and unportable
string-comparison test for infinities, and use isinf() instead.
(We do need some additional #include and "-lm" infrastructure to use
that in a contrib module, per prior experiences.)

In passing, prevent the regression test results from depending on DROP
CASCADE order; I've not seen that malfunction, but it's trouble waiting
to happen.

Discussion: https://postgr.es/m/E1f3MMJ-0006bf-B0@gemulon.postgresql.org

contrib/jsonb_plperl/Makefile

@@ -11,6 +11,8 @@ DATA = jsonb_plperlu--1.0.sql jsonb_plperl--1.0.sql
 
 REGRESS = jsonb_plperl jsonb_plperlu
 
+SHLIB_LINK += $(filter -lm, $(LIBS))
+
 ifdef USE_PGXS
 PG_CONFIG = pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)

contrib/jsonb_plperl/expected/jsonb_plperl.out

@@ -39,15 +39,30 @@ SELECT testSVToJsonb();
  1
 (1 row)
 
+-- unsupported (for now)
 CREATE FUNCTION testRegexpToJsonb() RETURNS jsonb
 LANGUAGE plperl
 TRANSFORM FOR TYPE jsonb
 AS $$
-return ('1' =~ m(0\t2));
+my $a = qr/foo/;
+return ($a);
 $$;
 SELECT testRegexpToJsonb();
 ERROR:  cannot transform this Perl type to jsonb
 CONTEXT:  PL/Perl function "testregexptojsonb"
+-- this revealed a bug in the original implementation
+CREATE FUNCTION testRegexpResultToJsonb() RETURNS jsonb
+LANGUAGE plperl
+TRANSFORM FOR TYPE jsonb
+AS $$
+return ('1' =~ m(0\t2));
+$$;
+SELECT testRegexpResultToJsonb();
+ testregexpresulttojsonb 
+-------------------------
+ 0
+(1 row)
+
 CREATE FUNCTION roundtrip(val jsonb) RETURNS jsonb
 LANGUAGE plperl
 TRANSFORM FOR TYPE jsonb
@@ -201,11 +216,6 @@ SELECT roundtrip('{"1": {"2": [3, 4, 5]}, "2": 3}');
  {"1": {"2": [3, 4, 5]}, "2": 3}
 (1 row)
 
+\set VERBOSITY terse \\ -- suppress cascade details
 DROP EXTENSION plperl CASCADE;
-NOTICE:  drop cascades to 6 other objects
-DETAIL:  drop cascades to extension jsonb_plperl
-drop cascades to function testhvtojsonb()
-drop cascades to function testavtojsonb()
-drop cascades to function testsvtojsonb()
-drop cascades to function testregexptojsonb()
-drop cascades to function roundtrip(jsonb)
+NOTICE:  drop cascades to 7 other objects

contrib/jsonb_plperl/expected/jsonb_plperlu.out

@@ -39,15 +39,30 @@ SELECT testSVToJsonb();
  1
 (1 row)
 
+-- unsupported (for now)
 CREATE FUNCTION testRegexpToJsonb() RETURNS jsonb
 LANGUAGE plperlu
 TRANSFORM FOR TYPE jsonb
 AS $$
-return ('1' =~ m(0\t2));
+my $a = qr/foo/;
+return ($a);
 $$;
 SELECT testRegexpToJsonb();
 ERROR:  cannot transform this Perl type to jsonb
 CONTEXT:  PL/Perl function "testregexptojsonb"
+-- this revealed a bug in the original implementation
+CREATE FUNCTION testRegexpResultToJsonb() RETURNS jsonb
+LANGUAGE plperlu
+TRANSFORM FOR TYPE jsonb
+AS $$
+return ('1' =~ m(0\t2));
+$$;
+SELECT testRegexpResultToJsonb();
+ testregexpresulttojsonb 
+-------------------------
+ 0
+(1 row)
+
 CREATE FUNCTION roundtrip(val jsonb) RETURNS jsonb
 LANGUAGE plperlu
 TRANSFORM FOR TYPE jsonb
@@ -201,11 +216,6 @@ SELECT roundtrip('{"1": {"2": [3, 4, 5]}, "2": 3}');
  {"1": {"2": [3, 4, 5]}, "2": 3}
 (1 row)
 
+\set VERBOSITY terse \\ -- suppress cascade details
 DROP EXTENSION plperlu CASCADE;
-NOTICE:  drop cascades to 6 other objects
-DETAIL:  drop cascades to extension jsonb_plperlu
-drop cascades to function testhvtojsonb()
-drop cascades to function testavtojsonb()
-drop cascades to function testsvtojsonb()
-drop cascades to function testregexptojsonb()
-drop cascades to function roundtrip(jsonb)
+NOTICE:  drop cascades to 7 other objects

contrib/jsonb_plperl/jsonb_plperl.c

 #include "postgres.h"
 
+#include <float.h>
+#include <math.h>
+
+/* Defined by Perl */
 #undef _
 
 #include "fmgr.h"
 #include "plperl.h"
 #include "plperl_helpers.h"
-
 #include "utils/jsonb.h"
 #include "utils/fmgrprotos.h"
 
@@ -188,46 +191,51 @@ SV_to_JsonbValue(SV *in, JsonbParseState **jsonb_state, bool is_elem)
 		case SVt_PVHV:
 			return HV_to_JsonbValue((HV *) in, jsonb_state);
 
-		case SVt_NV:
-		case SVt_IV:
+		case SVt_NULL:
+			out.type = jbvNull;
+			break;
+
+		default:
+			if (SvIOK(in))
 			{
-				char	   *str = sv2cstr(in);
+				IV			ival = SvIV(in);
 
-				/*
-				 * Use case-insensitive comparison because infinity
-				 * representation varies across Perl versions.
-				 */
-				if (pg_strcasecmp(str, "inf") == 0)
+				out.type = jbvNumeric;
+				out.val.numeric =
+					DatumGetNumeric(DirectFunctionCall1(int8_numeric,
+														Int64GetDatum((int64) ival)));
+			}
+			else if (SvNOK(in))
+			{
+				double		nval = SvNV(in);
+
+				if (isinf(nval))
 					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 (errmsg("cannot convert infinite value to jsonb"))));
 
 				out.type = jbvNumeric;
-				out.val.numeric = DatumGetNumeric(DirectFunctionCall3(numeric_in,
-																	  CStringGetDatum(str), 0, -1));
+				out.val.numeric =
+					DatumGetNumeric(DirectFunctionCall1(float8_numeric,
+														Float8GetDatum(nval)));
+			}
+			else if (SvPOK(in))
+			{
+				out.type = jbvString;
+				out.val.string.val = sv2cstr(in);
+				out.val.string.len = strlen(out.val.string.val);
+			}
+			else
+			{
+				/*
+				 * XXX It might be nice if we could include the Perl type in
+				 * the error message.
+				 */
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 (errmsg("cannot transform this Perl type to jsonb"))));
+				return NULL;
 			}
-			break;
-
-		case SVt_NULL:
-			out.type = jbvNull;
-			break;
-
-		case SVt_PV:			/* string */
-			out.type = jbvString;
-			out.val.string.val = sv2cstr(in);
-			out.val.string.len = strlen(out.val.string.val);
-			break;
-
-		default:
-
-			/*
-			 * XXX It might be nice if we could include the Perl type in the
-			 * error message.
-			 */
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 (errmsg("cannot transform this Perl type to jsonb"))));
-			return NULL;
 	}
 
 	/* Push result into 'jsonb_state' unless it is a raw scalar. */

contrib/jsonb_plperl/sql/jsonb_plperl.sql

@@ -34,16 +34,29 @@ $$;
 SELECT testSVToJsonb();
 
 
+-- unsupported (for now)
 CREATE FUNCTION testRegexpToJsonb() RETURNS jsonb
 LANGUAGE plperl
 TRANSFORM FOR TYPE jsonb
 AS $$
-return ('1' =~ m(0\t2));
+my $a = qr/foo/;
+return ($a);
 $$;
 
 SELECT testRegexpToJsonb();
 
 
+-- this revealed a bug in the original implementation
+CREATE FUNCTION testRegexpResultToJsonb() RETURNS jsonb
+LANGUAGE plperl
+TRANSFORM FOR TYPE jsonb
+AS $$
+return ('1' =~ m(0\t2));
+$$;
+
+SELECT testRegexpResultToJsonb();
+
+
 CREATE FUNCTION roundtrip(val jsonb) RETURNS jsonb
 LANGUAGE plperl
 TRANSFORM FOR TYPE jsonb
@@ -83,4 +96,5 @@ SELECT roundtrip('{"1": "string1"}');
 SELECT roundtrip('{"1": {"2": [3, 4, 5]}, "2": 3}');
 
 
+\set VERBOSITY terse \\ -- suppress cascade details
 DROP EXTENSION plperl CASCADE;

contrib/jsonb_plperl/sql/jsonb_plperlu.sql

@@ -34,16 +34,29 @@ $$;
 SELECT testSVToJsonb();
 
 
+-- unsupported (for now)
 CREATE FUNCTION testRegexpToJsonb() RETURNS jsonb
 LANGUAGE plperlu
 TRANSFORM FOR TYPE jsonb
 AS $$
-return ('1' =~ m(0\t2));
+my $a = qr/foo/;
+return ($a);
 $$;
 
 SELECT testRegexpToJsonb();
 
 
+-- this revealed a bug in the original implementation
+CREATE FUNCTION testRegexpResultToJsonb() RETURNS jsonb
+LANGUAGE plperlu
+TRANSFORM FOR TYPE jsonb
+AS $$
+return ('1' =~ m(0\t2));
+$$;
+
+SELECT testRegexpResultToJsonb();
+
+
 CREATE FUNCTION roundtrip(val jsonb) RETURNS jsonb
 LANGUAGE plperlu
 TRANSFORM FOR TYPE jsonb
@@ -83,4 +96,5 @@ SELECT roundtrip('{"1": "string1"}');
 SELECT roundtrip('{"1": {"2": [3, 4, 5]}, "2": 3}');
 
 
+\set VERBOSITY terse \\ -- suppress cascade details
 DROP EXTENSION plperlu CASCADE;