Further plperl cleanup: be more paranoid about checking the type of

data returned from Perl.  Consolidate multiple bits of code to convert
a Perl hash to a tuple, and drive the conversion off the keys present
in the hash rather than the tuple column names, so we detect error if
the hash contains keys it shouldn't.  (This means keys not in the hash
will silently default to NULL, which seems ok to me.)  Fix a bunch of
reference-count leaks too.

src/pl/plperl/test/test.expected

@@ -119,9 +119,9 @@ CREATE OR REPLACE FUNCTION perl_set() RETURNS SETOF testrowperl AS $$
     ];
 $$  LANGUAGE plperl;
 SELECT perl_set();
-ERROR:  plperl: check your return value structure
+ERROR:  plperl: element of result array is not a reference to hash
 SELECT * FROM perl_set();
-ERROR:  plperl: check your return value structure
+ERROR:  plperl: element of result array is not a reference to hash
 CREATE OR REPLACE FUNCTION perl_set() RETURNS SETOF testrowperl AS $$
     return [
         { f1 => 1, f2 => 'Hello', f3 =>  'World' },
@@ -202,7 +202,7 @@ ERROR:  could not determine row description for function returning record
 SELECT * FROM perl_record_set();
 ERROR:  a column definition list is required for functions returning "record"
 SELECT * FROM perl_record_set() AS (f1 integer, f2 text, f3 text);
-ERROR:  plperl: check your return value structure
+ERROR:  plperl: element of result array is not a reference to hash
 CREATE OR REPLACE FUNCTION perl_record_set() RETURNS SETOF record AS $$
     return [
         { f1 => 1, f2 => 'Hello', f3 =>  'World' },
@@ -222,3 +222,81 @@ SELECT * FROM perl_record_set() AS (f1 integer, f2 text, f3 text);
   3 | Hello | PL/Perl
 (3 rows)
 
+CREATE TYPE footype AS (x INTEGER, y INTEGER);
+CREATE OR REPLACE FUNCTION foo_good() RETURNS SETOF footype AS $$
+return [
+    {x => 1, y => 2},
+    {x => 3, y => 4}
+];
+$$ LANGUAGE plperl;
+SELECT * FROM foo_good();
+ x | y 
+---+---
+ 1 | 2
+ 3 | 4
+(2 rows)
+
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+    return {y => 3, z => 4};
+$$ LANGUAGE plperl;
+SELECT * FROM foo_bad();
+ERROR:  plperl: invalid attribute "z" in hash
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+return 42;
+$$ LANGUAGE plperl;
+SELECT * FROM foo_bad();
+ERROR:  plperl: composite-returning function must return a reference to hash
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+return [
+    [1, 2],
+    [3, 4]
+];
+$$ LANGUAGE plperl;
+SELECT * FROM foo_bad();
+ERROR:  plperl: composite-returning function must return a reference to hash
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+    return 42;
+$$ LANGUAGE plperl;
+SELECT * FROM foo_set_bad();
+ERROR:  plperl: set-returning function must return reference to array
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+    return {y => 3, z => 4};
+$$ LANGUAGE plperl;
+SELECT * FROM foo_set_bad();
+ERROR:  plperl: set-returning function must return reference to array
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+return [
+    [1, 2],
+    [3, 4]
+];
+$$ LANGUAGE plperl;
+SELECT * FROM foo_set_bad();
+ERROR:  plperl: element of result array is not a reference to hash
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+return [
+    {y => 3, z => 4}
+];
+$$ LANGUAGE plperl;
+SELECT * FROM foo_set_bad();
+ERROR:  plperl: invalid attribute "z" in hash
+CREATE OR REPLACE FUNCTION perl_get_field(footype, text) RETURNS integer AS $$
+    return $_[0]->{$_[1]};
+$$ LANGUAGE plperl;
+SELECT perl_get_field((11,12), 'x');
+ perl_get_field 
+----------------
+             11
+(1 row)
+
+SELECT perl_get_field((11,12), 'y');
+ perl_get_field 
+----------------
+             12
+(1 row)
+
+SELECT perl_get_field((11,12), 'z');
+ perl_get_field 
+----------------
+               
+(1 row)
+

src/pl/plperl/test/test_queries.sql

@@ -134,3 +134,80 @@ $$  LANGUAGE plperl;
 SELECT perl_record_set();
 SELECT * FROM perl_record_set();
 SELECT * FROM perl_record_set() AS (f1 integer, f2 text, f3 text);
+
+--
+-- Check behavior with erroneous return values
+--
+
+CREATE TYPE footype AS (x INTEGER, y INTEGER);
+
+CREATE OR REPLACE FUNCTION foo_good() RETURNS SETOF footype AS $$
+return [
+    {x => 1, y => 2},
+    {x => 3, y => 4}
+];
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_good();
+
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+    return {y => 3, z => 4};
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_bad();
+
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+return 42;
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_bad();
+
+CREATE OR REPLACE FUNCTION foo_bad() RETURNS footype AS $$
+return [
+    [1, 2],
+    [3, 4]
+];
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_bad();
+
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+    return 42;
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_set_bad();
+
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+    return {y => 3, z => 4};
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_set_bad();
+
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+return [
+    [1, 2],
+    [3, 4]
+];
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_set_bad();
+
+CREATE OR REPLACE FUNCTION foo_set_bad() RETURNS SETOF footype AS $$
+return [
+    {y => 3, z => 4}
+];
+$$ LANGUAGE plperl;
+
+SELECT * FROM foo_set_bad();
+
+--
+-- Check passing a tuple argument
+--
+
+CREATE OR REPLACE FUNCTION perl_get_field(footype, text) RETURNS integer AS $$
+    return $_[0]->{$_[1]};
+$$ LANGUAGE plperl;
+
+SELECT perl_get_field((11,12), 'x');
+SELECT perl_get_field((11,12), 'y');
+SELECT perl_get_field((11,12), 'z');