pg_dump: fix mis-dumping of non-global default privileges.

Non-global default privilege entries should be dumped as-is,
not made relative to the default ACL for their object type.
This would typically only matter if one had revoked some
on-by-default privileges in a global entry, and then wanted
to grant them again in a non-global entry.

Per report from Boris Korzun.  This is an old bug, so back-patch
to all supported branches.

Neil Chen, test case by Masahiko Sawada

Discussion: https://postgr.es/m/111621616618184@mail.yandex.ru
Discussion: https://postgr.es/m/CAA3qoJnr2+1dVJObNtfec=qW4Z0nz=A9+r5bZKoTSy5RDjskMw@mail.gmail.com

src/bin/pg_dump/pg_dump.c

@@ -9562,10 +9562,27 @@ getDefaultACLs(Archive *fout, int *numDefaultACLs)
 		PQExpBuffer initacl_subquery = createPQExpBuffer();
 		PQExpBuffer initracl_subquery = createPQExpBuffer();
 
+		/*
+		 * Global entries (with defaclnamespace=0) replace the hard-wired
+		 * default ACL for their object type.  We should dump them as deltas
+		 * from the default ACL, since that will be used as a starting point
+		 * for interpreting the ALTER DEFAULT PRIVILEGES commands.  On the
+		 * other hand, non-global entries can only add privileges not revoke
+		 * them.  We must dump those as-is (i.e., as deltas from an empty
+		 * ACL).  We implement that by passing NULL as the object type for
+		 * acldefault(), which works because acldefault() is STRICT.
+		 *
+		 * We can use defaclobjtype as the object type for acldefault(),
+		 * except for the case of 'S' (DEFACLOBJ_SEQUENCE) which must be
+		 * converted to 's'.
+		 */
 		buildACLQueries(acl_subquery, racl_subquery, initacl_subquery,
 						initracl_subquery, "defaclacl", "defaclrole",
 						"pip.initprivs",
-						"CASE WHEN defaclobjtype = 'S' THEN 's' ELSE defaclobjtype END::\"char\"",
+						"CASE WHEN defaclnamespace = 0 THEN"
+						"	  CASE WHEN defaclobjtype = 'S' THEN 's'::\"char\""
+						"	  ELSE defaclobjtype END "
+						"ELSE NULL END",
 						dopt->binary_upgrade);
 
 		appendPQExpBuffer(query, "SELECT d.oid, d.tableoid, "

src/bin/pg_dump/t/002_pg_dump.pl

@@ -443,6 +443,25 @@ my %tests = (
 		},
 	},
 
+	'ALTER DEFAULT PRIVILEGES FOR ROLE regress_dump_test_role GRANT EXECUTE ON FUNCTIONS'
+	  => {
+		create_order => 15,
+		create_sql   => 'ALTER DEFAULT PRIVILEGES
+					   FOR ROLE regress_dump_test_role IN SCHEMA dump_test
+					   GRANT EXECUTE ON FUNCTIONS TO regress_dump_test_role;',
+		regexp => qr/^
+			\QALTER DEFAULT PRIVILEGES \E
+			\QFOR ROLE regress_dump_test_role IN SCHEMA dump_test \E
+			\QGRANT ALL ON FUNCTIONS  TO regress_dump_test_role;\E
+			/xm,
+		like =>
+		  { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+		unlike => {
+			exclude_dump_test_schema => 1,
+			no_privs                 => 1,
+		},
+	  },
+
 	'ALTER DEFAULT PRIVILEGES FOR ROLE regress_dump_test_role REVOKE' => {
 		create_order => 55,
 		create_sql   => 'ALTER DEFAULT PRIVILEGES